PLUG POWER INC

1. Nature of Operations

Description of Business

While we continue to develop commercially viable hydrogen and fuel cell product solutions, we have expanded our offerings to support a variety of commercial operations that can be powered with clean hydrogen. We provide electrolyzers that allow customers — such as refineries, producers of chemicals, steel, fertilizer and commercial refueling stations — to generate hydrogen on-site. We are focusing our efforts on (a) industrial mobility applications, including electric forklifts and electric industrial vehicles, at multi-shift high volume manufacturing and high throughput distribution sites where we believe our products and services provide a unique combination of productivity, flexibility, and environmental benefits; and (b) production of hydrogen. Plug expects to support these products and customers with an ecosystem of vertically integrated products that produce, transport, store and handle, dispense, and use hydrogen for mobility and power applications.

GenDrive: GenDrive is our hydrogen fueled PEM fuel cell system, providing power to material handling EVs, including Class 1, 2, 3 and 6 electric forklifts, automated guided vehicles, and ground support equipment.

GenFuel: GenFuel is our liquid hydrogen fueling, delivery, generation, storage, and dispensing system.

GenCare: GenCare is our ongoing “Internet of Things”-based maintenance and on-site service program for GenDrive fuel cell systems, GenSure fuel cell systems, GenFuel hydrogen storage and dispensing products.

GenKey: GenKey is our vertically integrated “turn-key” solution combining either GenDrive or GenSure fuel cell power with GenFuel fuel and GenCare aftermarket service, offering complete simplicity to customers transitioning to fuel cell power.

GenEco Electrolyzers: The design and implementation of 5MW and 10MW electrolyzer systems that are modular, scalable hydrogen generators optimized for clean hydrogen production. Electrolyzers generate hydrogen from water using electricity and can produce “green” hydrogen when powered by renewable energy inputs, such as solar or wind power.

Liquefaction Systems: Plug’s 15 ton-per-day and 30 ton-per-day liquefiers are engineered for high efficiency, reliability, and operational flexibility — providing consistent liquid hydrogen to customers. This design increases plant reliability and availability while minimizing parasitic losses like heat leak and seal gas losses.

GenSure: GenSure is our stationary fuel cell solution providing scalable, modular PEM fuel cell power to support applications on both a small and large power scale. For smaller applications, Plug’s Low Power GenSure supports backup and grid-support application of the telecommunications, transportation, and utility sectors. Our High Power GenSure product line supports large scale stationary power, EV charging infrastructure, and data center markets.

Liquid Hydrogen: Liquid hydrogen provides an efficient fuel alternative to fossil-based energy. We produce liquid hydrogen at our production facilities in Tennessee, Georgia and Louisiana and through third-party supply arrangements, utilizing electrolyzer systems and liquefaction systems. Liquid hydrogen supply is used by customers in material handling operations, fuel cell electric vehicle fleets, and stationary power applications.

We provide our products and solutions worldwide through our direct sales force, and by leveraging relationships with original equipment manufacturers (“OEMs”) and their dealer networks. Plug is currently targeting Europe, Australia, North America and select international markets (including parts of Asia) for expansion in adoption of its hydrogen and electrolyzer solutions.

Our wholly-owned subsidiary, Plug Power LA JV, LLC, created a joint venture with Niloco Hydrogen Holdings LLC, a wholly-owned subsidiary of Olin Corporation (“Olin”), named “Hidrogenii” in the third quarter of 2022. We believe Hidrogenii will support reliability of supply and speed to market for hydrogen throughout North America and set the foundation for broader collaboration between Plug and Olin. The joint venture’s 15-ton-per-day hydrogen production plant in St. Gabriel, Louisiana commenced operations in April 2025. Hidrogenii is owned 50% by Plug Power LA JV, LLC and 50% by Niloco Hydrogen Holdings LLC.

Our wholly-owned subsidiary, Plug Power España S.L. (“Plug Power Spain”), entered into a joint venture with Acciona, named AccionaPlug S.L., in the fourth quarter of 2021. The joint venture intends to develop clean hydrogen projects in Spain and Portugal. AccionaPlug S.L. is owned 50% by Plug Power Spain and 50% by Acciona and has received initial project financing commitments.

Plug Power Inc. entered into a joint venture with SK Innovation Co., Ltd (“SK Innovation”) named SK Plug Hyverse Co. Ltd. (“SK Plug Hyverse”), owned 49% by the Company and 51% by SK Innovation. On December 31, 2025, the Company executed a share purchase agreement (the “Share Purchase Agreement”) with SK Innovation pursuant to which the Company agreed to sell, and SK Innovation agreed to purchase, the Company’s entire 49% equity interest in SK Plug Hyverse. The Company received $6.5 million in cash in connection with the sale.

Plug Power Inc. has also invested in a hydrogen infrastructure and growth equity fund, Clean H2 Infra Fund, a special limited partnership registered in France, since the fourth quarter of 2021. The Clean H2 Infra Fund is focused on clean hydrogen infrastructure through financing projects in the production, storage and distribution of clean hydrogen. As of December 31, 2025 the Company’s ownership percentage in the Clean H2 Infra Fund was approximately 5%.

Liquidity and Capital Resources

The Company has continued to experience negative cash flows from operations and net losses. The Company incurred net losses of approximately $1.7 billion, $2.1 billion and $1.4 billion for the years ended December 31, 2025, 2024 and 2023, respectively. The Company’s working capital was $799.7 million as of December 31, 2025, which included unrestricted cash and cash equivalents of $368.5 million and current restricted cash of $186.7 million.

The Company’s primary sources of liquidity have historically included cash on hand, proceeds from equity and debt financings, and operating cash flows. The Company continues to evaluate opportunities to strengthen its balance sheet and enhance financial flexibility. As part of its ongoing initiatives to strengthen the balance sheet and enhance liquidity, the Company initiated an infrastructure optimization initiative as described in Note 29, “Subsequent Events.” If completed as expected, the initiative is reasonably likely to improve the Company’s near-term liquidity position. However, the timing and ultimate magnitude of the impact will depend on execution, satisfaction of closing conditions, market conditions and other factors.

The future use of the Company’s available liquidity will be based upon the ongoing review of the funding needs of the Company’s businesses, the optimal allocation of its resources, and the timing of cash flow generation. To the extent that we desire to access alternative sources of capital, market conditions could adversely impact our ability to do so at that time and at terms favorable to the Company.

The Company has an “at-the-market” equity offering program with B. Riley Securities, Inc. (“B. Riley”) pursuant to which the Company may, from time to time, offer and sell through or to B. Riley, as sales agent or principal, shares of the Company’s common stock, having an aggregate gross sales price of up to $1.0 billion under a sales agreement. On August 15, 2025, the Company and B. Riley amended the “at-the-market” equity offering program to extend the term. The “at-the-market” equity offering program will terminate upon the earliest of (a) August 15, 2027, (b) the sale of all shares of common stock under the program or (c) termination of the sales agreement. On September 29, 2025, the Company and B. Riley amended the “at-the-market” equity offering program to add Yorkville Securities, LLC (“Yorkville”) as an

additional sales agent and/or principal through which the Company may offer and sell shares pursuant to the “at-the-market” equity offering program. During the year ended December 31, 2025, the Company sold 34,573,529 shares of common stock at a weighted-average sales price of $1.62 per share for gross proceeds of $55.9 million with related issuance costs of $1.0 million through the “at-the-market” equity program offering. As of December 31, 2025, the Company had $944.1 million of aggregate gross sales price of shares available to be sold under the “at-the-market” equity offering program.

The Company has also entered into a Standby Equity Purchase Agreement (the “SEPA”) with Yorkville, pursuant to which the Company has the right, at its option, to sell to Yorkville up to $1.0 billion in the aggregate gross sales price of its common stock, subject to certain limitations and conditions set forth therein. The Company has the right, but not the obligation, from time to time at its sole discretion to direct Yorkville to purchase directly from the Company up to $10.0 million in the aggregate gross sales price of its common stock on any trading day. The SEPA expires on February 10, 2027. During the year ended December 31, 2025, the Company soldno shares of common stock pursuant to the SEPA.

The Company believes that its working capital, cash position and restricted cash to be released over the next 12 months, together with other key assumptions, support the Company’s conclusion that it has sufficient capital to fund its on-going operations for a period of at least 12 months subsequent to the issuance of the accompanying consolidated financial statements. Key assumptions are based on factors such as forecasted sales and costs, amortization requirements of the Company’s finance obligations, the Company’s right to direct B. Riley and Yorkville to purchase shares from the Company under the “at-the-market” equity offering program, and the Company’s right to direct Yorkville to purchase shares from the Company under the SEPA.

2. Summary of Significant Accounting Policies

Principles of Consolidation

The consolidated financial statements include the financial statements of the Company and its wholly-owned subsidiaries. Intercompany balances and transactions have been eliminated in consolidation. In addition, we include our share of the results of our joint venture AccionaPlug S.L., our investment in Clean H2 Infra Fund and our former joint venture SK Plug Hyverse using the equity method based on our economic ownership interest and our ability to exercise significant influence over the operating and financial decisions of AccionaPlug S.L., Clean H2 Infra Fund and SK Plug Hyverse.

We consolidate all entities we control under either the voting interest model, which generally applies when we hold a majority of the voting interest of an entity, or the variable interest model, which applies to arrangements for which we are the primary beneficiary of a VIE. For consolidated subsidiaries in which our ownership is less than 100%, the outside shareholders’ interests are reflected as non-controlling interest on our consolidated financial statements. We are considered the primary beneficiary of a VIE when we have both the power to direct the activities that most significantly impact the economic performance of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. We are the primary beneficiary of Hidrogenii and consolidate the joint venture within our single reportable segment. For additional information, refer to Note 28, “Variable Interest Entities.”

Use of Estimates

The consolidated financial statements of the Company have been prepared in conformity with U.S. generally accepted accounting principles, which require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an on-going basis, we evaluate our estimates and judgments, including but not limited to those related to revenue recognition, valuation of inventories, valuation of long-lived assets, valuation of investments, valuation of convertible senior notes and long-term debt, accrual for service loss contracts, operating and finance leases, common stock warrants, stock-based compensation and contingencies. We base our estimates and judgments on historical experience and on various other factors and assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about (1) the carrying values of assets and liabilities and (2) the amount of revenue and expenses realized that

are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

Revenue Recognition

The Company enters into contracts that may contain one or a combination of fuel cell systems and infrastructure, installation, maintenance, spare parts, fuel delivery and other support services. Contracts containing fuel cell systems and related infrastructure may be sold directly to customers or provided to customers under a Power Purchase Agreement (“PPA”). The Company also enters into contracts that contain electrolyzer stacks, systems, maintenance, and other support services. Furthermore, the Company enters into contracts related to the sales of cryogenic equipment, liquefaction systems and engineered equipment.

The Company does not include a right of return on its products other than rights related to standard warranty provisions that permit repair or replacement of defective goods. The Company accrues for anticipated standard warranty costs at the same time that revenue is recognized for the related product, or when circumstances indicate that warranty costs will be incurred, as applicable. Any prepaid amounts would only be refunded to the extent services have not been provided or the fuel cell systems or infrastructure have not been delivered*.*

Revenue is measured based on the transaction price specified in a contract with a customer, subject to the allocation of the transaction price to distinct performance obligations as discussed below. The Company recognizes revenue when it satisfies a performance obligation by transferring a product or service to a customer.

Promises to the customer are separated into performance obligations and are accounted for separately if they are (1) capable of being distinct and (2) distinct in the context of the contract. The Company considers a performance obligation to be distinct if the customer can benefit from the good or service either on its own or together with other resources readily available to the customer and the Company’s promise to transfer the goods or service to the customer is separately identifiable from other promises in the contract. The Company allocates revenue to each distinct performance obligation based on relative standalone selling prices.

Payment terms for sales of fuel cells, infrastructure, and service to customers are typically 30 to 90 days from shipment of the goods. Payment terms on electrolyzer systems are typically based on achievement of milestones over the term of the contract with the customer. Service is prepaid upfront in a majority of the arrangements. The Company does not adjust the transaction price for a significant financing component when the performance obligation is expected to be fulfilled within a year.

The Company has issued to each of Amazon.com NV Investment Holdings LLC and Walmart warrants to purchase shares of the Company’s common stock. The Company presents the provision for common stock warrants within each revenue-related line item on the consolidated statements of operations. This presentation reflects the discount that those common stock warrants represent, and therefore revenue is net of these non-cash charges. The provision of common stock warrants is allocated to the relevant revenue-related line items based upon the expected mix of the revenue for each respective contract. On December 30, 2025, the Company entered into an agreement with Walmart pursuant to which the Company agreed to grant Walmart a contingent, limited-use license to access and use certain escrowed GenKey System-related materials and to forfeit all vested portions of the Walmart warrant and the unvested portions of the Walmart warrant were cancelled. See Note 18, “Share-Based Consideration Payable to a Customer,” for further information.

Nature of goods and services

The following is a description of principal activities from which the Company generates its revenue.

Revenue from sales of fuel cell systems, related infrastructure, and equipment represents sales of our GenDrive units, GenSure stationary backup power units, as well as hydrogen fueling infrastructure.

The Company uses a variety of information sources in determining standalone selling prices for fuel cells systems and the related infrastructure. For GenDrive fuel cells, given the nascent nature of the Company’s market, the Company considers several inputs, including prices from a limited number of standalone sales as well as the Company’s negotiations with customers. The Company also considers its costs to produce fuel cells as well as comparable list prices in estimating standalone selling prices. The Company uses applicable observable evidence from similar products in the market to determine standalone selling prices for GenSure stationary backup power units and hydrogen fueling infrastructure. The determination of standalone selling prices of the Company’s performance obligations requires significant judgment, including periodic assessment of pricing approaches and available observable evidence in the market. Once relative standalone selling prices are determined, the Company proportionately allocates the transaction price to each performance obligation within the customer arrangement based upon standalone selling price. The allocated transaction price related to fuel cell systems and spare parts is recognized as revenue at a point in time which usually occurs upon delivery (and occasionally at time of shipment). Revenue on hydrogen infrastructure installations is generally recognized at the point at which transfer of control passes to the customer, which usually occurs upon customer acceptance of the hydrogen infrastructure. The Company uses an input method to determine the amount of revenue to recognize during each reporting period when such revenue is recognized over time, based on the costs incurred to satisfy the performance obligation.

(ii)Sales of electrolyzer systems and solutions

Revenue from sales of electrolyzer systems and solutions represents sales of electrolyzer stacks and systems used to generate hydrogen for various applications including mobility, ammonia production, methanol production, power to gas, and other uses.

The Company uses a variety of information sources in determining standalone selling prices for electrolyzer systems solutions. Electrolyzer stacks are typically sold on a standalone basis and the standalone selling price is the contractual price with the customer. The Company uses an adjusted market assessment approach to determine the standalone selling price of electrolyzer systems. This includes considering both standalone selling prices of the systems by the Company and available information on competitor pricing on similar products. The determination of standalone selling prices of the Company’s performance obligations requires judgment, including periodic assessment of pricing approaches and available observable evidence in the market. Once relative standalone selling prices are determined, the Company proportionately allocates the transaction price to each performance obligation within the customer arrangement based upon standalone selling price. Revenue on electrolyzer systems and stacks is generally recognized at the point at which transfer of control passes to the customer, which usually occurs upon title transfer at shipment or delivery to the customer location. In certain instances, control of electrolyzer systems transfers to the customer over time, and the related revenue is recognized over time as the performance obligation is satisfied. We recognize revenue over time when contract performance results in the creation of a product for which we do not have an alternative use and the contract includes an enforceable right to payment in an amount that corresponds directly with the value of the performance completed. In these instances, we use an input measure (cost-to-total cost or percentage-of-completion method) of progress to determine the amount of revenue to recognize during each reporting period based on the costs incurred to satisfy the performance obligation.

Payments received from customers are recorded within deferred revenue and contract assets in the consolidated balance sheets until control is transferred. The related cost of such product and installation is also deferred as a component of deferred cost of revenue in the consolidated balance sheets until control is transferred.

(iii)Sales of cryogenic equipment and other

Revenue from sales of cryogenic equipment represents sales of liquefaction system and other cryogenic equipment such as trailers and mobile storage equipment for the distribution of liquefied hydrogen, oxygen, argon, nitrogen and other cryogenic gases.

Revenue on liquefaction systems is generally recognized over time when contract performance results in the creation of a product for which we do not have an alternative use and the contract includes an enforceable right to payment in an amount that corresponds directly with the value of the performance completed. In these instances, we use an input measure of progress to determine the amount of revenue to recognize during each reporting period based on the costs

incurred to satisfy the performance obligation. Control transfers to the customer over time, and the related revenue is recognized over time as the performance obligation is satisfied.

Revenue on cryogenic equipment is generally recognized at the point at which transfer of control passes to the customer, which usually occurs upon title transfer at shipment or delivery to the customer location.

Payments received from customers are recorded within deferred revenue and contract assets in the consolidated balance sheets until control is transferred. The related costs of such product and installation is also deferred as a component of deferred cost of revenue in the consolidated balance sheets until control is transferred.

Revenue from services performed on fuel cell systems and related infrastructure represents revenue earned on our service and maintenance contracts and sales of spare parts. The Company uses an adjusted market assessment approach to determine standalone selling prices for services. This approach considers market conditions and constraints while maximizing the use of available observable inputs obtained from a limited number of historical standalone service renewal prices and negotiations with customers. The transaction price allocated to services as discussed above is generally recognized as revenue over time on a straight-line basis over the expected service period, as customers simultaneously receive and consume the benefits of routine, recurring maintenance performed throughout the contract period.

In substantially all of its transactions, the Company sells extended maintenance contracts that generally provide for afive-to-ten-year service period from the date of product installation in exchange for an up-front payment. Services include monitoring, technical support, maintenance and related services. These services are accounted for as a separate performance obligation, and accordingly, revenue generated from these transactions, subject to the proportional allocation of transaction price, is deferred and recognized as revenue over the term of the contract, generally on a straight-line basis. Additionally, the Company may enter into annual service and extended maintenance contracts that are billed monthly. Revenue generated from these transactions is recognized as revenue on a straight-line basis over the term of the contract. Costs are recognized as incurred over the term of the contract. When costs are projected to exceed revenues over the life of the extended maintenance contract, an accrual for loss contracts is recorded. Costs are estimated based upon historical experience and consider the estimated impact of the Company’s cost reduction initiatives, if any. The actual results may differ from these estimates. See “Extended Maintenance Contracts” below.

Extended maintenance contracts generally do not contain customer renewal options. Upon expiration, customers may either negotiate a contract extension or switch to purchasing spare parts and maintaining the fuel cell systems on their own.

Revenue from PPAs primarily represents payments received from customers who make monthly payments to access the Company’s GenKey solution.

Revenue associated with these agreements is recognized on a straight-line basis over the life of the agreements as the customers simultaneously receive and consume the benefits from the Company’s performance of the services. The customers receive services ratably over the contract term.

Revenue associated with fuel delivered to customers represents the sale of hydrogen to customers that has been purchased by the Company from a third party or generated at our hydrogen production plants. Depending on the terms of the contract, revenue is recognized either upon delivery or upon consumption. The stand-alone selling price is not estimated because it is sold separately and therefore directly observable.

The Company produces hydrogen fuel onsite or purchases hydrogen fuel from suppliers and sells it to its customers. Revenue and cost of revenue related to this fuel is included in the respective fuel delivered to customers and related equipment lines on the consolidated statements of operations.

Other revenue includes sales of electrolyzer engineering and design services. The scope of these services includes establishing and defining project technical requirements, standards and guidelines as well as assistance in scoping and scheduling of large-scale electrolyzer solutions.

Income Taxes

Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in the period that includes the enactment date. A valuation allowance is recorded to reduce the carrying amounts of deferred tax assets if it is more likely than not that such assets will not be realized.

The Company accounts for uncertain tax positions in accordance with FASB ASC No. 740-10-25,Income Taxes-Overall-Recognition. The Company recognizes in its consolidated financial statements the impact of a tax position only if that position is more likely than not to be sustained on audit, based on the technical merits of the position. The Company recognizes interest and penalties related to unrecognized tax benefits on the interest expense line and other expense, net line, respectively, in the accompanying consolidated statements of operations.

Foreign Currency Translation

Foreign currency translation adjustments arising from conversion of the Company’s foreign subsidiary’s financial statements to U.S. dollars for reporting purposes are included in accumulated other comprehensive loss on the consolidated balance sheets. Transaction gains and losses resulting from the effect of exchange rate changes on transactions denominated in currencies other than the functional currency of the Company’s operations give rise to realized foreign currency transaction gains and losses and are included in other expense, net in the consolidated statements of operations.

Research and Development

Activities that qualify as research and development under ASC 730,Research and Development (“ASC 730”) include: (i) laboratory research aimed at discovery of new knowledge; (ii) searching for applications of new research findings or other knowledge; (iii) conceptual formulation and design of possible product or process alternatives; (iv) testing in search for or evaluation of product or process alternatives; (v) modification of the formulation or design of a product or process: (vi) design, construction, and testing of preproduction prototypes and models; (vii) design of tools, jigs, molds, and dies involving new technology; (viii) design, construction, and operation of a pilot plant that is not of a scale economically feasible to the entity for commercial production; (ix) engineering activity required to advance the design of a product to the point that it meets specific functional and economic requirements and is ready for manufacture; and (x) design and development of tools used to facilitate research and development or components of a product or process that are undergoing research and development activities. Costs related to research and development activities by the Company are expensed as incurred.

Stock-based Compensation

The Company maintains employee stock-based compensation plans, which are described more fully in Note 19, “Employee Benefit Plans.” Stock-based compensation represents the cost related to stock-based awards granted to employees and directors. The Company measures stock-based compensation cost at grant-date, based on the fair value of the award, and recognizes the cost as expense on a straight-line basis over the option’s requisite service period. Forfeitures are recognized as they occur.

The Company estimates the fair value of stock-based awards using a Black-Scholes valuation model. Stock-based compensation expense is recorded in cost of revenue associated with sales of fuel cell systems, related infrastructure and equipment, cost of revenue for services performed on fuel cell systems and related infrastructure, research and

development expense and selling, general and administrative expenses in the consolidated statements of operations based on the employees’ respective function.

The Company has also issued market condition stock options awards that include a market condition. The grant date fair value of market condition stock options awards is estimated using a Monte Carlo simulation model and the cost is recognized using the accelerated attribution method.

Government Assistance

The operation of our business is impacted by various government programs, incentives, and other arrangements. Government incentives are recorded in our consolidated financial statements in accordance with their purpose as a reduction of expense, or an offset to the related capital asset. Under a government grant model, once it is reasonably assured that the entity will comply with the conditions of the grant, the grant money should be recognized on a systematic basis over the period in which the entity recognizes the related expenses or losses for which the grant money is intended to compensate. The Company recognizes grants once it is probable that both of the following conditions will be met: (1) the Company is eligible to receive the grant and (2) the Company is able to comply with the relevant conditions of the grant. For more information, see Note 27, “Government Assistance.”

Cash and Cash Equivalents

For purposes of the consolidated statements of cash flows, the Company considers all highly-liquid debt instruments with original maturities of three months or less to be cash equivalents. Due to their short-term nature, the carrying amounts reported in the consolidated balance sheets approximate the fair value of cash and cash equivalents. The Company’s cash and cash equivalents are deposited with financial institutions located in the U.S. and may at times exceed insured limits.

Restricted Cash

Restricted cash consists primarily of cash that serves as support for leasing arrangements. Any cash that is legally restricted from use is classified as restricted cash. If the purpose of restricted cash relates to acquiring a long-term asset, liquidating a long-term liability, or is otherwise unavailable for a period longer than one year from the balance sheet date, the restricted cash is included in other long-term assets. Otherwise, restricted cash is included in other current assets in the consolidated balance sheets.

Accounts Receivable

Accounts receivable are stated at the amount billed or billable to customers and are ordinarily due between 30 and 120 days after the issuance of the invoice. Receivables are reserved or written off based on individual credit evaluation and specific circumstances of the customer. The allowance for expected credit losses for current accounts receivable is based primarily on past collections experience relative to the length of time receivables are past due; however, when available evidence reasonably supports an assumption that counterparty credit risk over the expected payment period will differ from current and historical payment collections, a forecasting adjustment will be reflected in the allowance for expected credit losses. The allowance for credit losses and related receivable are reduced when the amount is deemed uncollectible.

Inventory

Inventories are valued at the lower of cost, determined on a first-in, first-out basis, and net realizable value. All inventory, including spare parts inventory held at service locations, is not relieved until the customer has received the product, at which time the customer obtains control of the goods. We maintain inventory levels adequate for our short-term needs within the next twelve months based upon present levels of production. An allowance for potential non-saleable inventory due to damaged, excess stock or obsolescence is based upon a detailed review of inventory, past history, and expected usage. The Company's estimate of the inventory valuation adjustments utilizes certain inputs and involves judgment. The Company evaluates excess and obsolescence and lower of cost or net realizable values throughout the course of the year and, as necessary, adjusts inventory based upon a variety of factors, including historical usage, forecasted usage and sales, product obsolescence, anticipated selling price, and anticipated cost to complete to determine product

margin and other factors. We review all contracts related to product lines with projected negative margins that are arranged to be sold at a loss in the future as the basis for a lower of cost or net realizable value adjustment.

Property, Plant and Equipment

Property, plant and equipment are originally recorded at cost or, if acquired as part of a business combination, at fair value. Maintenance and repairs are expensed as costs are incurred. Depreciation on plant and equipment is calculated on the straight-line method over the estimated useful lives of the assets. Gains and losses resulting from the sale of property and equipment are recorded in current operations. Included within machinery and equipment is certain equipment related to our hydrogen plants. The Company records depreciation and amortization over the following estimated useful lives:

Equipment Related to PPAs and Fuel Delivered to Customers

Equipment related to PPAs and fuel delivered to customers primarily consists of the assets deployed related to PPAs and sites where we deliver fuel to customers as well as equipment related to failed sale/leaseback transactions. Equipment is depreciated over its useful life. Depreciation expense is recorded on a straight-line basis and is included in cost of revenue for PPAs or cost of fuel delivered to customers, respectively, in the consolidated statements of operations.

Investments in Non-consolidated Entities and Non-marketable Securities

The Company accounts for its investments in non-consolidated entities AccionaPlug S.L., SK Plug Hyverse (sold in December 2025) and Clean H2 Infra Fund as equity method investments. In accordance with ASC 323,Investments – Equity Method and Joint Ventures (“ASC 323”), we apply the equity method of accounting when we have the ability to exercise significant influence but do not control the operating and financial decisions of an investee. Under the equity method, we initially record our investment at cost and subsequently adjust the investment to recognize our share of net earnings or losses, distributions received and other-than-temporary impairments. Equity method investments are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investment may not be recoverable.

Included in “Investments in non-consolidated entities and non-marketable securities” on the consolidated balance sheets are equity investments without readily determinable fair values (“non-marketable securities”). Under ASC 321,Investments – Equity Securities (“ASC 321”), non-marketable securities that do not qualify for equity method accounting are measured at cost, less any impairment and adjusted for changes resulting from observable price changes in orderly transactions for the identical or similar investments of the same issuer.

Additionally, included in “Prepaid expenses, tax credits, and other current assets” on the consolidated balance sheets is an investment in a non-marketable debt security that was classified as held-to-maturity and was scheduled to mature within the next twelve months. In accordance with ASC 320,Investments – Debt Securities (“ASC 320”), the held-to-maturity debt security is held at amortized cost and are subject to periodic impairment reviews. In accordance with ASC 326,Financial Instruments – Credit Losses (“ASC 326”), we determine whether a credit loss exists by considering information about the collectability of the instrument, current market conditions, and reasonable and supportable forecasts of economic conditions. We recognize an allowance for credit losses and write down the amortized cost basis of the investment if it is more likely than not we will be required or we intend to sell the investment before recovery of its amortized cost basis.

Leases

The Company is a lessee in noncancelable (1) operating leases, primarily related to sale/leaseback transactions with financial institutions for deployment of the Company’s products at certain customer sites, and (2) finance leases. The Company accounts for leases in accordance with ASC 842, as amended.

The Company determines if an arrangement is or contains a lease at contract inception. The Company recognizes a right of use asset and a lease liability at the lease commencement date. For operating leases, the lease liability is initially measured at the present value of the unpaid lease payments at the lease commencement date. For finance leases, the lease liability is initially measured in the same manner and date as for operating leases and is subsequently measured at amortized cost using the effective interest method.

Key estimates and judgments include how the Company determines (1) the discount rate it uses to discount the unpaid lease payments to present value, (2) the lease term, and (3) the lease payments.

The right of use asset is initially measured at cost, which comprises the initial amount of the lease liability adjusted for lease payments made at or before the lease commencement date, plus any initial direct costs incurred less any lease incentives received. For operating leases, the right of use asset is subsequently measured throughout the lease term at the carrying amount of the lease liability, plus initial direct costs, plus (minus) any prepaid (accrued) lease payments, less the unamortized balance of lease incentives received. Lease expense for lease payments is recognized on a straight-line basis over the lease term.

For finance leases, the right of use asset is subsequently amortized using the straight-line method from the lease commencement date to the earlier of the end of the useful life of the underlying asset or the end of the lease term unless the lease transfers ownership of the underlying asset to the Company or the Company is reasonably certain to exercise an option to purchase the underlying asset. In those cases, the right of use asset is amortized over the useful life of the underlying asset. Amortization of the right of use asset is recognized and presented separately from interest expense on the lease liability.

The Company monitors for events or changes in circumstances that require a reassessment of its leases. When a reassessment results in the remeasurement of a lease liability, a corresponding adjustment is made to the carrying amount of the corresponding right of use asset.

Operating and finance lease right of use assets are presented separately on the Company’s consolidated balance sheets. The current portions of operating and finance lease liabilities are also presented separately within current liabilities and the long-term portions are presented separately within noncurrent liabilities on the consolidated balance sheets.

The Company has elected not to recognize right of use assets and lease liabilities for short-term leases that have a lease term of 12 months or less. The Company recognizes the lease payments associated with its short-term leases as an expense on a straight-line basis over the lease term.

Intangible Assets

Intangible assets consist of acquired technology, dry stack electrolyzer technology and customer relationships, trade name and other finite intangibles and are amortized using a straight-line method over their useful lives.

Impairment

Impairment: Property, Equipment, Leasehold Improvements, and Finite-lived Intangible Assets

Long-lived assets, such as property, equipment, leasehold improvements, and finite-lived intangible assets, are reviewed for impairment whenever events and circumstances indicate that the carrying amount of an asset may not be recoverable in accordance with ASC 360,Property, Plant, and Equipment(“ASC 360”). If circumstances require a long-lived asset or asset group to be tested for impairment, the Company first compares undiscounted cash flows expected to be generated by that asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment is recognized to the extent that the carrying amount exceeds its fair value. In making these determinations, the Company uses certain assumptions, including, but not limited to: (i) estimated fair value of the assets; and (ii) estimated, undiscounted future cash flows expected to be generated by these assets, which are based on additional assumptions such as asset utilization, length of service, the asset will be used in the Company’s operations, and (iii) estimated residual values. Fair value is determined using various valuation techniques including discounted cash flow models, quoted market values and third-party independent appraisals, as considered necessary.

Impairment: PPA Executory Contract Considerations

We evaluate PPA assets throughout the course of the year to identify events or changes in circumstances (“triggering events”) that indicate the carrying value of certain assets may not be recoverable. PPA assets that we evaluate include right of use lease assets, equipment deployed to our PPAs, and assets related primarily to our fuel delivery business.

Upon the occurrence of a triggering event, PPA assets are evaluated on a per-site basis to determine if the carrying amounts are recoverable. The determination of recoverability is made based upon the estimated undiscounted future net cash flows of assets grouped at the lowest level for which there are identifiable cash flows independent of the cash flows of other groups. For operating assets, the Company has generally determined that the lowest level of identifiable cash flows is based on the customer sites. The assets related primarily to our fuel delivery business are considered to be their own asset group. The cash flows are estimated based on the remaining useful life of the primary asset within the asset group.

For assets related to our PPA agreements, we consider all underlying cash inflows related to our contract revenues and cash outflows relating to the costs incurred to service the PPAs. Our cash flow estimates used in the recoverability test are based upon, among other things, historical results adjusted to reflect our best estimate of future cash flows and operating performance. Development of future cash flows also requires us to make assumptions and to apply judgment, including timing of future expected cash flows, future cost savings initiatives, and determining recovery values. Changes to our key assumptions related to future performance and other economic and market factors could adversely affect the outcome of our recoverability tests and cause more asset groups to be tested for impairment.

If the estimated undiscounted future net cash flows for a given asset group are less than the carrying amount of the related asset group, an impairment loss is determined by comparing the estimated fair value with the carrying amount of the asset group. The impairment loss is then allocated to the assets in the asset group based on the asset’s relative carrying amounts. However, assets are not impaired below their then estimated fair values. Fair value is generally determined through various valuation techniques, including discounted cash flow models, quoted market values and third-party independent appraisals, as well as year-over-year trends in pricing of our new equipment and overall evaluation of our industry and market, as considered necessary. The Company considers these indicators with certain of its own internal indices and metrics in determining fair value in light of the nascent state of the Company’s market and industry. The estimate of fair value represents our best estimates of these factors and is subject to variability. Changes to our key assumptions related to future performance and other economic and market factors could adversely affect our impairment evaluation.

Impairment: ROU Assets

The Company evaluates ROU assets in accordance with ASC 360. The primary assets underlying the ROU balances are GenDrive units and hydrogen infrastructure utilized in PPA executory contracts with customers. ROU assets are evaluated throughout the course of the year to identify events or changes in circumstances (“triggering events”) that indicate the carrying value of certain assets may not be recoverable. Upon the occurrence of a triggering event, the ROU assets are evaluated to determine if the carrying amounts are recoverable. The determination of recoverability is made based upon the estimated undiscounted future net cash flows of assets grouped at the lowest level for which there are identifiable cash flows independent of the cash flows of other groups. The Company has generally determined that the lowest level of identifiable cash flows is based on the customer sites. The ROU carrying value is allocated to the various assets under the related lease agreement based on the initial revenue recognized at the execution of the sale lease back agreement. The cash inflows are the contract revenues from the PPA customer and the cash outflows are derived from costs incurred to service the assets under the PPA agreements. Cash flow estimates used in the recoverability test are based upon, among other things, historical results adjusted to reflect our best estimate of future cash flows and operating performance. The development of future cash flows also requires the Company to make assumptions and to apply judgment, including the timing of future expected cash flows, future cost savings initiatives, and determining recovery values. Changes to key assumptions related to future performance and other economic and market factors could adversely affect the outcome of our recoverability tests and cause more asset groups to be tested for impairment.

If the estimated undiscounted future net cash flows for a given asset group are less than the carrying amount of the related asset group, an impairment loss is determined by comparing the estimated fair value with the carrying amount of the ROU. Assets are not impaired below their then estimated fair values. To determine fair value the Company determined a fair value of a lease using a market rent. Market rent assumptions included useful life and discount rate. The estimate of fair value represents our best estimates of these factors and is subject to variability. Changes to the key assumptions related to future performance and other economic and market factors could adversely affect our impairment evaluation.

Impairment: Contract Assets

The Company assesses contract assets for impairment when there is a significant change in facts and circumstances of the underlying contract in accordance with ASC 606,Revenue from Contracts with Customers (“ASC 606”) and ASC 310,Receivables(“ASC 310”). Impairment loss is recognized when it is probable that the Company will be unable to collect the contract consideration to which it is entitled from the customer. The Company does not recognize any additional revenue from the underlying contract.

Impairment: Investments in Non-consolidated Entities and Non-marketable Securities

For the Company’s investments in non-consolidated entities and non-marketable securities, the Company evaluates throughout the course of the year whether any indicators of impairment exist in accordance with ASC 320,Investments — Debt Securities (“ASC 320”), ASC 321,Investments — Equity Securities (“ASC 321”) and ASC 323,Investments — Equity Method and Joint Ventures(“ASC 323”).

Common Stock Warrant Accounting

The Company accounts for common stock warrants as either derivative liabilities or as equity instruments depending on the specific terms of the respective warrant agreements. Common stock warrants that meet certain applicable requirements of ASC Subtopic 815-40,Derivatives and Hedging – Contracts in Entity’s Own Equity, and other related guidance are accounted for as equity instruments. The Company classifies these equity instruments within additional paid-in capital on the consolidated balance sheets.

Common stock warrants accounted for as equity instruments represent the warrants issued to Amazon and Walmart as discussed in Note 18, “Share-Based Consideration Payable to a Customer.” The Company adopted FASB ASU 2019-08,Compensation – Stock Compensation (Topic 718) andRevenue from Contracts with Customers (Topic 606), which requires entities to measure and classify share-based payment awards granted to a customer. On December 30, 2025,

the Company entered into an agreement with Walmart in which Walmart agreed to forfeit all vested portions of the Walmart warrant. The unvested portions of the Walmart warrant were cancelled and accordingly, no shares of common stock will become issuable by the Company in connection with the Walmart warrant.

In order to calculate warrant charges, the Company used the Black-Scholes pricing model, which required key inputs including volatility and risk-free interest rate and certain unobservable inputs for which there is little or no market data, requiring the Company to develop its own assumptions. The Company estimated the fair value of unvested warrants, considered to be probable of vesting, at the time. Based on that estimated fair value, the Company determined warrant charges, which are recorded as a reduction of revenue in the consolidated statements of operations.

Common stock warrants accounted for as a liability are the warrants issued to purchase up to 185,430,464 shares of the Company’s common stock at $7.75 per share as discussed in Note 12, “Warrant Liabilities.” Under the terms of the $7.75 Warrants, upon a Change of Control (as defined in the $7.75 Warrants), the holder may elect to require the Company (or successor entity) to purchase the warrant for cash equal to its Black-Scholes value (a “Change of Control Cash Election”). This Change of Control Cash Election right is not contingent upon other equity holders of the Company receiving the same consideration and is exercisable at the election of the warrant holder irrespective of the form of consideration payable to other holders of the Company’s securities in such transaction. As such, the $7.75 Warrants were recorded on the consolidated balance sheets as a liability because the Change of Control Cash Election represents a conditional obligation that could require the Company to settle the $7.75 Warrants for cash upon the occurrence of a Change of Control, which precludes equity classification under ASC 815.

The Company measures the $7.75 Warrants at fair value. Each period the fair value of the notes will be re-measured and resulting gains/losses from change in fair value will be recognized within the consolidated statements of operations. Refer to Note 8, “Fair Value Measurements,” for further information.

Extended Maintenance Contracts

On a quarterly basis, we evaluate any potential losses related to our extended maintenance contracts for fuel cell systems and related infrastructure that has been sold. We measure loss accruals at the customer contract level. The expected revenues and expenses for these contracts include all applicable expected costs of providing services over the remaining term of the contracts and the related unearned net revenue. A loss is recognized if the sum of expected costs of providing services under the contract exceeds related unearned net revenue and is recorded as a provision for loss contracts related to service in the consolidated statements of operations. As we continue to work to improve quality and reliability, unanticipated additional quality issues or warranty claims may arise and additional material charges may be incurred in the future. These quality issues could also adversely affect our contract loss accrual. The Company has undertaken and will undertake several other initiatives to extend the life and improve the reliability of its equipment. As a result of these initiatives and our additional expectation that the increase in certain costs will abate, the Company believes that its contract loss accrual is sufficient. However, if elevated service costs persist, the Company will adjust its estimated future service costs and increase its contract loss accrual estimate.

Product Warranty Reserve

In conjunction with certain product sales, we provide warranties that cover factors such as non-conformance to specifications and defects in material and design. Generally, sales of equipment and related infrastructure are accompanied by aone totwo year standard warranty. These warranties are included in the estimates to complete the related programs. The Company also repairs or replaces certain products or parts found to be defective under normal use and service with an item of equivalent value, at our option, without charge during the warranty period. We quantify and record an estimate for warranty-related costs based on our actual historical claims experience and current repair costs. We adjust accruals as warranty claims data and historical experience warrant.

Fair Value Measurements

The Company records the fair value of assets and liabilities in accordance with ASC 820,Fair Value Measurement(“ASC 820”). ASC 820 defines fair value as the price received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date and in the principal or most advantageous

market for that asset or liability. The fair value should be calculated based on assumptions that market participants would use in pricing the asset or liability, not on assumptions specific to the entity.

In addition to defining fair value, ASC 820 expands the disclosure requirements around fair value and establishes a fair value hierarchy for valuation inputs. The hierarchy prioritizes the inputs into three levels based on the extent to which inputs used in measuring fair value are observable in the market. Each fair value measurement is reported in one of the three levels, which is determined by the lowest level input that is significant to the fair value measurement in its entirety.

These levels are:

Convertible Senior Notes

In May 2020, the Company issued $212.5 million in aggregate principal amount of the 3.75% Convertible Senior Notes due 2025 (the “3.75% Convertible Senior Notes”) as described in Note 13, “Convertible Senior Notes.” The Company exchanged $138.8 million in aggregate principal amount of the 3.75% Convertible Senior Notes for $140.4 million in aggregate principal amount of the 7.00% Convertible Senior Notes due 2026 (the “7.00% Convertible Senior Notes”), also described in Note 13, “Convertible Senior Notes.” The Company accounts for its 7.00% Convertible Senior Notes as a liability measured at amortized cost. The Company uses the effective interest rate method to amortize the debt issuance costs to interest expense over the term of the 7.00% Convertible Senior Notes.

On November 21, 2025, the Company issued the 6.75% Convertible Senior Notes in the aggregate principal amount of $431.3 million pursuant to an indenture for a purchase price of $409.7 million as described in Note 13, “Convertible Senior Notes.” The Company elected to measure the 6.75% Convertible Senior Notes at fair value in accordance with the fair value option. Each period the fair value of the notes will be remeasured and resulting gains/losses from change in fair value will be recognized within the consolidated statements of operations, except for any changes in instrument-specific credit risk which will be separately presented in other comprehensive income. Refer to Note 8, “Fair Value Measurements,” for further information. The Company has elected as an accounting policy to present interest expense separately from the changes in fair value of the 6.75% Convertible Senior Notes.

Subsequent Events

The Company evaluates subsequent events at the date of the balance sheet as well as conditions that arise after the balance sheet date but before the consolidated financial statements are issued. The effects of conditions that existed at the balance sheet date are recognized in the consolidated financial statements. Events and conditions arising after the balance sheet date but before the consolidated financial statements are issued are evaluated to determine if disclosure is required to keep the consolidated financial statements from being misleading. To the extent such events and conditions exist, if any, disclosures are made regarding the nature of events and the estimated financial effects for those events and conditions. See Note 29, “Subsequent Events.”

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements

In December 2023, ASU 2023-09,Improvements to Income Tax Disclosures, was issued to require public business entities to annually disclose specific categories in the rate reconciliation and provide additional information for reconciling items that meet a quantitative threshold. Additionally, annual disclosures on income taxes paid will be required to be further disaggregated by federal, state, and foreign taxes. This update is effective for annual periods beginning after December 15, 2024. The Company has adopted the standard on a retrospective basis. Refer to Note 22, “Income Taxes.”

Recently Issued and Not Yet Adopted Accounting Pronouncements

In December 2025, Accounting Standards Update 2025-11 (“ASU 2025-11”),Interim Reporting (Topic 270): Narrow-Scope Improvements, was issued to improve the guidance in Topic 270 by improving the navigability of the required interim disclosures and clarifying when that guidance is applicable. The amendments also provide additional guidance on what disclosures should be provided in interim reporting periods and adds to Topic 270 a principle that requires entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. This standard is effective for annual periods, including interim reporting periods within annual reporting periods, beginning after December 15, 2027 with early adoption permitted. The Company has not yet adopted ASU 2025-11 and is still evaluating the impact of the adoptionon its consolidated financial statements.

In December 2025, Accounting Standards Update 2025-10 (“ASU 2025-10”),Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities, was issued to establish the accounting for a government grant received by a business entity, including guidance for: (1) a grant related to an asset; and (2) a grant related to income. This standard establishes authoritative guidance in generally accepted accounting principles in the United States (“GAAP”) about accounting for government grants received by business entities improves financial reporting by clarifying the appropriate accounting, reducing diversity in practice, and increasing consistency across business entities. This standard is effective for annual periods, including interim reporting periods within annual reporting periods, beginning after December 15, 2028 with early adoption permitted. The Company has not yet adopted ASU 2025-10 and is still evaluating the impact of the adoptionon its consolidated financial statements.

In July 2025, Accounting Standards Update 2025-05 (“ASU 2025-05”),Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets, was issued to address challenges encountered when applying the guidance in Topic 326 to current accounts receivable and current contract assets arising from transactions accounted for under Topic 606. This standard introduces a practical expedient for entities that assumes that current conditions as of the balance sheet date do not change for the remaining life of the asset. This standard is effective for annual periods, including interim reporting periods within annual reporting periods, beginning after December 15, 2025 with early adoption permitted. The adoption of this standardis not expected tohave a material impact on the Company’s consolidated financial statements.

In May 2025, Accounting Standards Update 2025-04 (“ASU 2025-04”),Clarifications to Share-Based Consideration Payable to a Customer, was issued to reduce diversity in practice and improve the decision usefulness and operability of the guidance for share-based consideration payable to a customer in conjunction with selling goods or services. This standard is effective for annual periods, including interim reporting periods within annual reporting periods, beginning after December 15, 2026 with early adoption permitted. The Company has not yet adopted ASU 2025-04 and is still evaluating the impact of the adoptionon its consolidated financial statements.

In November 2024, ASU 2024-04,Debt with Conversion and Other Options(“ASU 2024-04”), was issued to improve the relevance and consistency in application of the induced conversion guidance in Subtopic 470-20. This standard is effective for annual periods beginning after December 15, 2025, including interim periods within those fiscal years. The adoption of this standard is not expected to have a material impact on the Company’s consolidated financial statements.

In November 2024, ASU 2024-03,Disaggregation of Income Statement Expenses(“ASU 2024-03”), was issued which requires disclosure in the notes to the financial statements of specified information about certain costs and expenses. This standard is effective for annual periods beginning after December 15, 2026, and interim periods within annual periods beginning after December 15, 2027, on a prospective basis, with early adoption and retrospective application permitted. The Company has not yet adopted ASU 2024-03 and is still evaluating the impact of the adoption on its consolidated financial statements.

Climate Disclosures

In March 2024, the SEC issued Release No. 33-11275,The Enhancement and Standardization of Climate-Related Disclosures for Investors, which includes final rules that enhance the transparency of climate-related disclosures and require companies to disclose material climate-related risks; activities to mitigate or adapt to such risks; information about

the board of directors' oversight of climate-related risks and management’s role in managing material climate-related risks; and information on any climate-related targets or goals that are material to the registrant's business, results of operations, or financial condition. As a large accelerated filer, most disclosure requirements are effective for the Company beginning with the year ending December 31, 2025. The SEC has been the subject of various lawsuits since adopting these rules. As a result of ongoing litigation, the SEC issued an order in April 2024 to stay the effectiveness of the rules while judicial review is pending. We are continuing to monitor developments associated with these rules and are currently evaluating the impact of these rules on our consolidated financial statements and related disclosures.

3. Inventory

Inventory as of December 31, 2025 and 2024, consisted of the following (in thousands):

Inventory is comprised of raw materials and supplies, work-in-process, and finished goods. The Company has recorded reductions to inventory which comprised of excess and obsolete items and related lower of cost or net realizable value adjustments of $151.9 million and $158.9 million as of December 31, 2025 and 2024, respectively.

4. Property, Plant and Equipment

Property, plant and equipment at December 31, 2025 and 2024 consisted of the following (in thousands):

The decrease in the Company’s property, plant and equipment balance was primarily due to impairment. The Company recorded impairment charges totaling of $661.3 million, $681.2 million and $3.1 million for the years ended December 31, 2025, 2024 and 2023, respectively. Refer to Note 21, “Impairment,” for further information.

Construction in progress is primarily comprised of hydrogen production equipment and facilities in development. Completed assets are transferred to their respective asset classes, and depreciation begins when an asset is ready for its intended use. Interest on outstanding debt is capitalized during periods of capital asset construction and amortized over the useful lives of the related assets.

Depreciation expense related to property, plant and equipment was $25.4 million, $42.8 million and $33.3 million for the years ended December 31, 2025, 2024 and 2023, respectively.

5. Equipment Related to Power Purchase Agreements and Fuel Delivered to Customers, Net

Equipment related to power purchase agreements and fuel delivered to customers, net, as of December 31, 2025 and 2024 consisted of the following (in thousands):

As of December 31, 2025 and 2024, the Company had deployed assets at customer sites that had associated PPAs. These PPAs expire over the next one to ten years. PPAs contain termination clauses with associated penalties, the amount of which cause the likelihood of cancellation to be remote.

Depreciation expense was $5.8 million, $9.3 million and $8.0 million for the years ended December 31, 2025, 2024 and 2023, respectively.

The Company recorded impairment charges of $23.9 million, $1.6 million and $0.2 million for the years ended December 31, 2025, 2024 and 2023, respectively. Refer to Note 21, “Impairment,” for further information.

6. Intangible Assets

The gross carrying amount and accumulated amortization of the Company’s acquired identifiable intangible assets as of December 31, 2025 were as follows (in thousands):

The gross carrying amount and accumulated amortization of the Company’s acquired identifiable intangible assets as of December 31, 2024 were as follows (in thousands):

The change in the gross carrying amount of the acquired technology and customer relationships, trade name and other during the year ended December 31, 2025 was primarily due to the Company recording impairment charges of $48.9 million. The Company recorded impairment charges of $79.7 million and $20 thousand during the years ended December 31, 2024 and 2023, respectively. Refer to Note 21, “Impairment,” for further information.

Amortization expense for acquired identifiable intangible assets for the years ended December 31, 2025, 2024 and 2023 was $7.0 million, $23.4 million and $19.1 million, respectively. Of the total amortization expense for the year ended December 31, 2024, $7.2 million was due to accelerated amortization which resulted from the Company’s annual impairment analysis.

Estimated amortization expense for subsequent years is as follows (in thousands):

7. Investments

Investments in Non-consolidated Entities and Non-marketable Securities

Non-marketable Securities

Our investment in non-marketable securities was $12.8 million and $2.6 million as of December 31, 2025 and 2024, respectively, of which $10.2 million matures within the next 12 months and is included in prepaid expenses, tax credits, and other current assets on the Company’s consolidated balance sheets. During the year ended December 31, 2025, the Company made a $10.2 million investment in a non-marketable debt security that was classified as held-to-maturity. The held-to-maturity debt security was scheduled to mature in the fourth quarter of 2026.

Equity Method Investments

As of December 31, 2025 and 2024, the Company accounted for the following investments in the investee’s common stock under the equity method, which are included in the investments in non-consolidated entities and non-marketable securities on the consolidated balance sheets (amounts in thousands):

During the second quarter of 2025, the Company performed an evaluation of SK Plug Hyverse due to a decline in market conditions and determined that an other-than-temporary impairment existed. The Company determined that its ability and intent to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value resulted in an other-than-temporary impairment. The estimated fair value was based largely on the future cash flows expected to be generated by the investment using unobservable data points. As a result, the Company recorded an other-than-temporary impairment loss of $42.5 million for the year ended December 31, 2025 to loss on equity method investments in the consolidated statement of operations, which reduced the investments in non-consolidated entities and non-marketable securities financial statement line item on the consolidated balance sheets.

On December 31, 2025, the Company executed the Share Purchase Agreement with SK Innovation to sell its entire 49% equity interest in SK Plug Hyverse. The Company received aggregate cash proceeds of $6.5 million in connection with the sale.

During the year ended December 31, 2025, the Company contributed approximately $1.5 million, $0 and $8.2 million, respectively, to AccionaPlug S.L., SK Plug Hyverse and Clean H2 Infra Fund. During the year ended December 31, 2024, the Company contributed approximately $32.3 million, $2.9 million, $16.0 million and $17.4 million, respectively, to HyVia, AccionaPlug S.L., SK Plug Hyverse and Clean H2 Infra Fund.

The Company did not have any known capital commitments related to its equity method investments as of December 31, 2025.

8. Fair Value Measurements

The Company records the fair value of assets and liabilities in accordance with ASC 820. Refer to Note 2, “Summary of Significant Account Policies,” for further information.

There were no transfers between Level 1, Level 2, or Level 3 for the year ended December 31, 2025. Financial instruments not recorded at fair value on a recurring basis include equity method investments that have not been remeasured or impaired in the current period, such as our investments in AccionaPlug S.L. and Clean H2 Infra Fund. For the one equity method investment that was measured at fair value on a nonrecurring basis, refer to Note 7, “Investments,” for further information.

The following table summarizes the carrying amount and estimated fair value of the Company’s financial instruments at December 31, 2025 and 2024(in thousands):

Theliabilities measured at fair value on a recurring basis that are based on quoted prices for identical liabilities and are therefore categorized as Level 1 are the 6.75% Convertible Senior Notes and a portion of contingent consideration. Theliabilities measured at fair value on a recurring basis that have unobservable inputs and are therefore categorized as Level 3 are related to the$7.75 Warrants, a portion of contingent consideration and the 6.00% Convertible Debenture.

Assets and Liabilities Measured at Fair Value on a Recurring Basis

$7.75* Warrants*

The fair value of the$7.75 Warrants as of December 31, 2025 was comprised of a single financial liability under ASC 825,Financial Instruments(“ASC 825”), with changes in fair value recorded in gain/loss from changes in fair value of warrant liabilities recorded in the consolidated statements of operations.

The Company estimated and recorded the fair value of the$7.75 Warrants upon its issuance date of November 21, 2025 and as of December 31, 2025 based on a Black-Scholes Option Pricing Model. The valuations utilized significant Level 3 unobservable inputs, including volatility. Other significant assumptions include risk-free rate, exercise price, the Company’s common stock price and maturity date. Significant judgment is required in selecting the significant inputs and assumptions. Actual assumptions may differ from our current estimates and such differences could materially impact the fair value of the$7.75 Warrants.

Refer to Note 12, “Warrant Liabilities,” for the significant assumptions utilized in the fair value of the $7.75 Warrants at issuance and as of December 31, 2025, respectively, as well as the change in the carrying amount of the $7.75 Warrants for the year ended December 31, 2025.

6.75%* Convertible Senior Notes*

The fair value of the 6.75% Convertible Senior Notes as of December 31, 2025 was comprised of a single financial liability in which the Company elected the fair value option under ASC 825, with changes in fair value recorded in gain/loss from change in fair value of convertible debt instruments and debt within in the consolidated statements of operations. The

Company elected the fair value option due to its multiple conversions features required to be presented at fair value. The Company has also elected to present interest expense separately from the change in fair value of convertible debt instruments and debt measured at fair value through earnings. Total changes in the fair value of the liability that resulted from a change in the instrument-specific credit risk are separately recorded in other comprehensive income. There wasno change in the instrument-specific credit risk during the year ended December 31, 2025.

The Company recorded the fair value of the 6.75% Convertible Senior Notes upon its issuance date of November 21, 2025 at its cash value. The fair value of the 6.75% Convertible Notes as of December 31, 2025 utilized Level 1 inputs as it was based on the average par value of 99.9% for trades of the 6.75% Convertible Senior Notes made on December 30, 2025.

Refer to Note 13, “Convertible Senior Notes,” for the change in the carrying amount of the 6.75% Convertible Senior Notes for the year ended December 31, 2025.

Contingent consideration

The fair value of contingent consideration as of December 31, 2025 and 2024 was related to the Joule Processing LLC (“Joule”) acquisition in 2022 and the Frames Holding B.V. (“Frames”) acquisition in 2021.

In connection with the Joule acquisition, the Company initially recorded on its consolidated balance sheets a liability of$41.7 million representing the fair value of contingent consideration payable. The fair value of this contingent consideration was$9.4 million and$48.2 million as of December 31, 2025 and 2024, respectively. The decrease compared to the year ended December 31, 2024 was primarily due to adecrease of$21.2 million recorded in change in fair value of contingent consideration in the consolidated statements of operations during the year ended December 31, 2025. In addition, payments were made that reduced the fair value of the liability by $17.6 million during the year ended December 31, 2025. During 2025, the Company reached an agreement with Joule’s sellers to partially settle the outstanding balance of the contingent consideration. In accordance with the agreement,$2.0 million of the remaining$9.4 million contingent consideration liability as of December 31, 2025 will be paid during the first quarter of 2026 and is classified as a Level 1 measurement.

In connection with the Frames acquisition, the Company recorded on its consolidated balance sheets a liability of$29.1 million representing the fair value of contingent consideration payable. The fair value of this contingent consideration was$2.4 million and$12.5 million as of December 31, 2025 and 2024, respectively. During 2025, the Company entered into an agreement with Frames’ sellers to finalize the outstanding balance of the contingent consideration. The decrease compared to the year ended December 31, 2024 was primarily due to payments that reduced the fair value of the liability by$9.4 million. In addition, a decrease of$2.3 million was recorded in change in fair value of contingent consideration in the consolidated statements of operations for the year ended December 31, 2025. Partially offsetting these decreases, the fair value of the liability increased by$1.5 million during the year ended December 31, 2025 due to foreign currency translation losses. In accordance with the agreement, the remaining$2.4 million contingent consideration liability as of December 31, 2025 will be fully paid during the first quarter of 2026 and is classified as a Level 1 measurement.

Inthe consolidated balance sheets, contingent consideration was recorded in the contingent consideration, loss accrual for service contracts, and other liabilities financial statement line item, and was comprised of the following Level 3 unobservable inputs for the year ended December 31, 2025:

Inthe consolidated balance sheets, contingent consideration was recorded in the contingent consideration, loss accrual for service contracts, and other liabilities financial statement line item, and was comprised of the following unobservable inputs for the year ended December 31, 2024:

The change in the carrying amount of contingent consideration for the year ended December 31, 2025 was as follows (in thousands):

15.00%* Secured Debenture*

The fair value of the 15.00% Secured Debenture was comprised of a financial liability for the initial tranche of$190.4 million and a financial liability for the second tranche of$51.2 million in which the Company elected the fair value option for both tranches under ASC 825 with changes in fair value recorded in change in fair value of debt in the consolidated statements of operations.

The Company estimated and recorded the fair value of the initial tranche of the 15.00% Secured Debenture upon its issuance date of May 5, 2025. The Company estimated and recorded the fair value of the second tranche of the 15.00% Secured Debenture upon its issuance date of September 30, 2025. The fair values of the initial and second tranches of the 15.00% Secured Debenture 2025 were based on a Probability-Weighted Expected Return Method (“PWERM”). The PWERM includes the Discounted Cash Flow (“DCF”) method corresponding to the relevant amortization schedule in each scenario and a Black-Scholes Option Pricing Model was utilized to estimate the fair value of the 15.00% Secured Debenture Warrant. Additionally, based on the fair values of the initial and second tranches of the 15.00% Secured Debenture and the purchase price of the initial and second tranches, we estimated the implied yield at the valuation date. The valuations utilized significant Level 3 unobservable inputs, including implied yield, volatility, and risky discount rate. Other significant assumptions include risk-free rate, principal value, the Company’s common stock price and maturity date.

The 15.00% Secured Debenture was fully repaid during the fourth quarter of 2025 with a portion of the net proceeds from the issuance of the 6.75% Convertible Senior Notes. Refer to Note 14, “Long-Term Debt,” for the change in the carrying amount of the 15.00% Secured Debenture during the year ended December 31, 2025.

6.00%* Convertible Debenture*

The fair value of the 6.00% Convertible Debenture as of December 31, 2024 was comprised of a single financial liability in which the Company elected the fair value option under ASC 825, with changes in fair value recorded in gain/loss from changes in fair value of 6.00% Convertible Debenture recorded in the consolidated statements of operations.

The fair value of the 6.00% Convertible Debenture was based on a Monte Carlo simulation of stock price of the Company on a daily basis and a discounted cash flow model that incorporates the amortization schedule, contingent on the daily simulated stock price. The valuation utilized significant Level 3 unobservable inputs, including implied yield, volatility, and risky discount rate. Other significant assumptions include risk-free rate, principal value, the Company’s common stock price, maturity date and the various conversion features and prices per the agreement.

The 6.00% Convertible Debenture was fully repaid during the second quarter of 2025 with the net proceeds from the initial tranche of the 15.00% Secured Debenture. Refer to Note 13, “Convertible Senior Notes,” for the change in the carrying amount of the 6.00% Convertible Debenture for the year ended December 31, 2025.

Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis

In addition to assets and liabilities that are recorded at fair value on a recurring basis, impairment indicators may subject long-lived assets and finite-lived intangible assets to non-recurring fair value measurements. During the year ended December 31, 2025, property, plant and equipment, intangible assets, right of use assets related to finance leases, net and right of use assets related to operating leases, net were written down to their estimated fair values. The inputs to these models are considered to be Level 3 significant unobservable inputs.

The Level 3 significant unobservable inputs that were used in the valuation of the long-lived assets during 2025 were:

Refer to Note 21, “Impairment,” for further information.

9. Accrued Expenses

Accrued expenses at December 31, 2025 and 2024 consisted of (in thousands):

10. Operating and Finance Lease Liabilities

As of December 31, 2025, the Company had operating leases, as lessee, primarily associated with sale/leaseback transactions that are partially secured by restricted cash, security deposits and pledged escrows as summarized below. These leases expire over the nextone tofive years. Minimum rent payments under operating leases are recognized on a straight-line basis over the term of the lease.

Leases contain termination clauses with associated penalties, the amount of which cause the likelihood of cancellation to be remote. At the end of the lease term, the leased assets may be returned to the lessor by the Company,

the Company may negotiate with the lessor to purchase the assets at fair market value, or the Company may negotiate with the lessor to renew the lease at market rental rates. No residual value guarantees are contained in the leases. No financial covenants are contained within the lease, however there are customary operational covenants such as assurance the Company properly maintains the leased assets and carries appropriate insurance, etc. The leases include credit support in the form of either cash, collateral or letters of credit. See Note 25, “Commitments and Contingencies,” for a description of cash held as security associated with the leases.

The Company has finance leases primarily associated with its property and equipment at fueling customer locations.

Future minimum lease payments under operating and finance leases (with initial or remaining lease terms in excess of one year) as of December 31, 2025 were as follows (in thousands):

Rental expense for all operating leases was $77.8 million, $98.1 million, and $95.0 million for the years ended December 31, 2025, 2024 and 2023, respectively.

As of December 31, 2025 and 2024, security deposits associated with sale/leaseback transactions were $6.1 million and $7.4 million, respectively, and were included in other assets in the consolidated balance sheets.

The Company recorded impairment charges of $8.6 million, $145.4 million and $4.6 million for the years ended December 31, 2025, 2024 and 2023, respectively, related to its right of use assets related to operating leases, net. Refer to Note 21, “Impairment,” for further information.

Other information related to the operating leases are presented in the following table:

Finance lease costs include amortization of the right of use assets and interest on lease liabilities and were $7.3 million, $7.2 million and $7.5 million for the years ended December 31, 2025, 2024 and 2023, respectively.

As of December 31, 2025 and 2024, the gross carrying value of right of use assets associated with finance leases was $60.7 million and $51.8 million, respectively. The accumulated depreciation for these right of use assets was $15.8 million and $12.9 million at December 31, 2025 and 2024, respectively. The Company recorded impairment charges of $2.6 million, $0 and $0 for the years ended December 31, 2025, 2024 and 2023, respectively, related to its right of use assets related to finance leases, net. Refer to Note 21, “Impairment,” for further information.

Other information related to the finance leases are presented in the following table:

As of December 31, 2025, the Company had outstanding obligations to Wells Fargo, Pathward and U.S. Bank under several Master Lease Agreements totaling $97.4 million, $59.0 million and $48.0 million, respectively. As of December 31, 2024, the Company had outstanding obligations to Wells Fargo, Pathward and U.S. Bank under several Master Lease Agreements totaling $132.2 million, $56.9 million, and $66.7 million, respectively. These outstanding obligations are included in the operating lease liabilities and finance obligations financial statement line items on the consolidated balance sheets.

11. Finance Obligations

The Company has sold future services to be performed associated with certain sale/leaseback transactions and recorded the balance as a finance obligation. The outstanding balance of this obligation as of December 31, 2025 was $199.3 million, $69.2 million and $130.1 million of which was classified as short-term and long-term, respectively, on the accompanying consolidated balance sheets. The outstanding balance of this obligation as of December 31, 2024 was $276.7 million, $77.5 million and $199.2 million of which was classified as short-term and long-term, respectively, on the accompanying consolidated balance sheets. The amount was amortized using the effective interest method. Interest expense recorded related to finance obligations for the years ended December 31, 2025, 2024 and 2023 was $27.9 million, $36.7 million and $39.6 million, respectively.

In prior periods, the Company entered into sale/leaseback transactions that were accounted for as financing transactions and reported as part of finance obligations. The outstanding balance of the Company’s finance obligations related to sale/leaseback transactions as of December 31, 2025 was $68.7 million, $7.0 million and $61.7 million of which was classified as short-term and long-term, respectively, on the accompanying consolidated balance sheets with a residual value of $39.9 million. The outstanding balance of the Company’s finance obligations related to sale/leaseback transactions as of December 31, 2024 was $70.7 million, $5.6 million and $65.1 million of which was classified as short-term and long-term, respectively, on the accompanying consolidated balance sheets with a residual value of $37.7 million.

Future minimum payments under finance obligations notes above as of December 31, 2025 were as follows (in thousands):

Other information related to the above finance obligations are presented in the following table:

The fair value of the Company’s total finance obligations approximated their carrying value for the years ended December 31, 2025 and December 31, 2024.

12. Warrant Liabilities

On March 20, 2025, the Company sold 46,500,000 shares of its common stock, pre-funded warrants (the “Pre-Funded Warrants”) to purchase 138,930,464 shares of its common stock and warrants (the “Common Warrants”) to purchase 185,430,464 shares of its common stock in a registered direct offering pursuant to an underwriting agreement with several underwriters for aggregate gross proceeds of $279.9 million with $11.9 million of underwriting discounts and $0.5 million of related issuance costs.

On October 8, 2025, the Company entered into a warrant exercise inducement agreement with the holder of the Common Warrants, whereby in consideration for exercising the 185,430,464 outstanding Common Warrants at the exercise price as set forth in the Common Warrants of $2.00 per share, the Company agreed to provide to the holder new Common Warrants to purchase up to 185,430,464 shares of the Company’s common stock at $7.75 per share (the “$7.75 Warrants”). In addition, under the warrant exercise inducement agreement, the holder was permitted to receive, upon exercise, in lieu of 154,430,464 common shares, new pre-funded warrants to purchase 154,430,464 shares of the Company’s common stock at $0.0001 per share (the “New Pre-Funded Warrants”). Refer to Note 16, “Stockholders’ Equity,” for further information on the New Pre-Funded Warrants. As a result of the warrant exercise inducement transaction, the Company received net proceeds, after deducting $16.1 million of transaction expenses and fees, of $354.7 million and recorded a related inducement charge of $196.5 million to inducement of common warrant exercise in the consolidated statements of operations. Included within the inducement of the common warrant exercise charge of $196.5 million was the fair value of the $7.75 Warrants of $180.4 million and $16.1 million of transaction expenses and fees incurred in connection with the warrant exercise inducement agreement.

The$7.75 Warrants contain a provision pursuant to which, upon a Change of Control (as defined in the$7.75 Warrants), the holder may elect to require the Company (or the successor entity) to purchase the warrant for cash equal to its Black-Scholes value (a “Change of Control Cash Election”). As disclosed in Note 2, “Summary of Significant Accounting Policies,” the Company has classified the$7.75 Warrants as a liability on the consolidated balance sheets because the Change of Control Cash Election represents a conditional obligation that could require the Company to settle the warrants in cash upon the occurrence of a Change of Control, which precludes equity classification under ASC 815. The$7.75 Warrants became exercisable on February 28, 2026 and expire on March 20, 2028.

As of October 8, 2025 and December 31, 2025, the$7.75 Warrants were valued at $180.4 million and $52.3 million, respectively, using the following Black-Scholes assumptions:

The change in the carrying amount of the $7.75 Warrants for the year ended December 31, 2025 was as follows (in thousands):

13. Convertible Senior Notes

6.75% Convertible Senior Notes

On November 21, 2025, the Company issued $431.3 million aggregate principal amount of 6.75% Convertible Senior Notes, including the exercise in full of the initial purchasers’ option to purchase up to an additional $56.3 million principal amount of the notes. The notes were issued pursuant to an indenture, dated November 21, 2025 (the “Indenture”).

The notes are general unsecured obligations of the Company and rank senior in right of payment to all of its future indebtedness that is expressly subordinated in right of payment to the notes, equal in right of payment to all of its existing and future liabilities that are not so subordinated, effectively junior to all of its secured indebtedness, to the extent of the value of the assets securing such indebtedness, and structurally junior to all indebtedness and other liabilities of its subsidiaries. The notes bear interest at a rate of 6.75% per year. Interest is payable semi-annually in arrears on June 1 and December 1 of each year, beginning on June 1, 2026. The notes mature on December 1, 2033, unless earlier repurchased, redeemed or converted.

The notes may not be converted prior to the earlier of (i) February 28, 2026 and (ii) the “reserved share effective date” (as defined in the Indenture) (such earlier date, the “conversion limit end date”). On or after the conversion limit end date, the notes are convertible at the option of the holders at any time prior to the close of business on the second scheduled trading day immediately preceding the maturity date. Upon conversion, the Company will pay or deliver, as the case may be, cash, shares of the Company’s common stock, or a combination of cash and shares of common stock, at the Company’s election, in the manner and subject to the terms and conditions provided in the Indenture; provided that unless and until the reserved share effective date occurs, the Company will settle conversion of notes solely with cash.

The conversion rate of the notes will initially be 333.3333 shares of common stock per $1,000 principal amount of notes, which is equivalent to an initial conversion price of approximately $3.00 per share of common stock. The initial conversion price of the notes represents a premium of approximately 40% over the last reported sale price of $2.14 per share of common stock on The Nasdaq Capital Market on November 18, 2025. The conversion rate for the notes is subject to adjustment under certain circumstances in accordance with the terms of the Indenture. In addition, following certain corporate events that occur prior to the maturity date or if the Company delivers a notice of redemption in respect of the notes, the Company will, in certain circumstances, increase the conversion rate of the notes for a holder who elects to convert its notes in connection with such a corporate event or convert its notes called (or deemed called) for redemption during the related redemption period (as defined in the Indenture), as the case may be.

The Company may not redeem the notes prior to December 6, 2028. The Company may redeem for cash all or any portion of the notes (subject to certain limitations), at its option, on or after December 6, 2028 and prior to the 26th scheduled trading day immediately preceding the maturity date, if the last reported sale price of the common stock has been at least 130% of the conversion price for the notes then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. However, the Company may not redeem less than all of the outstanding notes unless at least $50.0 million aggregate principal amount of notes are outstanding and not called for redemption as of the time we send the related notice of redemption (and after giving effect to the delivery of such notice of redemption).

Holders of notes may require the Company to repurchase for cash all or any portion of their notes on December 6, 2029 at a repurchase price equal to 100% of the principal amount of notes to be repurchased, plus accrued and unpaid interest to, but excluding, December 6, 2029. In addition, if the Company undergoes a fundamental change (as defined in

the Indenture), then, subject to certain conditions and except as set forth in the Indenture, holders may require the Company to repurchase for cash all or any portion of their notes at a repurchase price equal to 100% of the principal amount of the notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

The Indenture includes customary covenants and sets forth certain events of default after which the notes may be declared immediately due and payable and sets forth certain types of bankruptcy or insolvency events of default involving the Company after which the notes become automatically due and payable. In case of certain bankruptcy and insolvency-related events of default with respect to the Company, the principal of, and accrued and unpaid interest on, all of the then outstanding notes shall automatically become due and payable. As of December 31, 2025, the Company is in compliance with all debt covenants associated with the 6.75% Convertible Senior Notes.

The offering price of the notes was 95% of the principal amount of notes. The net proceeds from the 6.75% Convertible Senior Notes was $400.0 million after deducting the initial purchasers’ discounts and commissions and offering expenses payable by the Company. The Company used net proceeds from the 6.75% Convertible Senior Notes to fully repay the outstanding principal amount of its 15.00% Secured Debenture and to repurchase $138.0 million aggregate principal amount of the Company’s 7.00% Convertible Senior Notes. See Note 14, “Long Term Debt,” for further information. There wereno conversion of the 6.75% Convertible Senior Notes during the year ended December 31, 2025.

The change in the carrying amount of the 6.75% Convertible Senior Notes for the year ended December 31, 2025 was as follows (in thousands):

The following table summarizes the total interest expense and effective interest rate related to the 6.75% Convertible Senior Notes during the year ended December 31, 2025 (in thousands, except for the effective interest rate):

6.00% Convertible Debenture

On November 11, 2024, the Company entered into the Debenture Purchase Agreement pursuant to which the Company issued to Yorkville the 6.00% Convertible Debenture in exchange for the payment of $190.0 million. The 6.00% Convertible Debenture was issued in a private placement in reliance upon an exemption from registration provided by Section 4(a)(2) of the Securities Act. The 6.00% Convertible Debenture ranked pari passu in right of payment with all other outstanding and future senior indebtedness of the Company.

The 6.00% Convertible Debenture was fully settled during 2025. The Company incurred losses on extinguishment of convertible debt instruments and debt of $9.1 million during the year ended December 31, 2025.

The change in the carrying amount of the 6.00% Convertible Debenture for the year ended December 31, 2025 was as follows (in thousands):

The following table summarizes the total interest expense and effective interest rate (prior period only) related to the 6.00% Convertible Debenture during the years ended December 31, 2025 and 2024 (in thousands, except for the effective interest rate):

7.00% Convertible Senior Notes

On March 20, 2024, the Company entered into separate, privately negotiated exchange agreements with certain holders of the Company’s outstanding 3.75% Convertible Senior Notes pursuant to which the Company exchanged $138.8 million in aggregate principal amount of the 3.75% Convertible Senior Notes, and accrued and unpaid interest of $1.6 million on such notes to, but excluding, March 20, 2024, for $140.4 million in aggregate principal amount of the Company’s new 7.00% Convertible Senior Notes due 2026, in each case, pursuant to the exemption from registration provided by Section 4(a)(2) under the Securities Act. Following the exchange, approximately $58.5 million in aggregate principal amount of the 3.75% Convertible Senior Notes remained outstanding with terms unchanged.

This transaction was accounted for as an extinguishment of debt. As a result, the Company recorded a loss on extinguishment of debt of $14.0 million in the consolidated statements of operations during the first quarter of 2024. Loss on extinguishment of debt arises from the difference between the net carrying amount of the Company’s debt and the fair value of the assets transferred to extinguish the debt.

In November 2025, the Company used net proceeds from the 6.75% Convertible Senior Notes to repurchase $138.0 million aggregate principal amount of the 7.00% Convertible Senior Notes in addition to $4.6 million of accrued interest. The Company incurred losses on extinguishment of convertible debt instruments and debt of $8.9 million during the year ended December 31, 2025. There wereno conversions of the 7.00% Convertible Senior Notes during the years ended December 31, 2025 and 2024.

As of December 31, 2025, the 7.00% Convertible Senior Notes consisted of the following (in thousands):

The following table summarizes the total interest expense and effective interest rate related to the 7.00% Convertible Senior Notes during the years ended December 31, 2025 and 2024 (in thousands, except for the effective interest rate):

3.75% Convertible Senior Notes

On May 18, 2020, the Company issued $200.0 million in aggregate principal amount of 3.75% Convertible Senior Notes due June 1, 2025 in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act. On May 29, 2020, the Company issued an additional $12.5 million in aggregate principal amount of 3.75% Convertible Senior Notes. On March 12, 2024, the Company exchanged $138.8 million in aggregate principal amount of the 3.75% Convertible Senior Notes for $140.4 million in aggregate principal amount of the Company’s new 7.00% Convertible Senior Notes due 2026. Following the exchange, approximately $58.5 million in aggregate principal amount of the 3.75% Convertible Senior Notes remained outstanding with terms unchanged.

During the year ended December 31, 2025, the Company paid cash of $59.6 million, which included $58.5 million to retire the remaining outstanding principal and $1.1 million to pay the remaining accrued interest, to fully settle the 3.75% Convertible Senior Notes.

The following table summarizes the total interest expense and effective interest rate (prior periods only) related to the 3.75% Convertible Senior Notes for the years ended December 31, 2025, 2024 and 2023 (in thousands, except for effective interest rate):

14. Long-Term Debt

15.00% Secured Debenture

On May 5, 2025, the Company issued the initial tranche of the 15.00% Secured Debenture in the aggregate principal amount of $210.0 million pursuant to the Secured Debenture Purchase Agreement with Yorkville for a purchase price of $199.5 million with a discount of $10.5 million. On September 30, 2025, the Company issued a portion of the second tranche of the 15.00% Secured Debenture in the aggregate principal amount of $52.5 million pursuant to the Secured Debenture Purchase Agreement with Yorkville for a purchase price of $49.9 million with a discount of $2.6 million. As discussed in Note 13, “Convertible Senior Notes,” on November 21, 2025 the Company issued the 6.75% Convertible Senior Notes and used a portion of the net proceeds from the transaction to fully repay the outstanding principal amount of its 15.00% Secured Debenture.

The 15.00% Secured Debenture was fully settled during 2025. The Company incurred losses on extinguishment of convertible debt instruments and debt of $13.5 million during the year ended December 31, 2025.

The following table shows change in the carrying amount of the 15.00% Secured Debenture during the year ended December 31, 2025 (in thousands):

The following table summarizes the total interest expense related to the 15.00% Secured Debenture during the year ended December 31, 2025:

15. Extended Maintenance Contracts and Warranty Reserve

Loss Accrual

On a quarterly basis, we evaluate any potential losses related to our extended maintenance contracts for sales of equipment, related infrastructure and other that have been sold. The following table shows the roll forward of balances in the accrual for loss contracts (in thousands):

The Company recorded a benefit for loss accrual primarily due to improved pricing structure as well as reductions in cost to service our GenDrive units due to improved stack reliability and increased labor utilization.

Product Warranty Reserve

On a quarterly basis, we evaluate our product warranty reserve. The Company applies a failure rate based on product type on a contract-by-contract basis to determine its product warranty reserve liability. The following table shows the roll forward of product warranty reserve (in thousands):

16. Stockholders’ Equity

Preferred Stock

The Company has authorized 5,000,000 shares of preferred stock, par value $0.01 per share, consisting of 170,000 shares of previously designated Series A Junior Participating Cumulative Preferred Stock and 4,830,000 shares of undesignated preferred stock. The Company’s amended and restated certificate of incorporation, as amended, provides that shares of preferred stock may be issued from time to time in one or more series. The Company’s Board of Directors is authorized to fix the voting rights, if any, designations, powers, preferences, qualifications, limitations, and restrictions thereof, applicable to the shares of each series. As of December 31, 2025 and 2024, there wereno shares of Series A Junior Participating Cumulative Preferred Stock issued and outstanding.

Common Stock

The Company has one class of common stock, par value $.01 per share. Each share of the Company’s common stock is entitled toone vote on all matters submitted to stockholders.

“At-the-Market” Equity Offering Program

On January 17, 2024, the Company entered into the Original ATM Agreement with B. Riley, pursuant to which the Company may, from time to time, offer and sell through or to B. Riley, as sales agent or principal, shares of the Company’s common stock, having an aggregate gross sales price of up to $1.0 billion. As of December 31, 2025, the Company had $944.1 million of aggregate gross sales price of shares available to be sold under the “at-the-market” equity offering program. Refer to Note 1, “Nature of Operations,” for further information.

15.00%* Secured Debenture Warrant*

On July 8, 2025, the Company issued to Yorkville the 15.00% Secured Debenture Warrant to purchase 31,500,000 shares of common stock with an exercise price of $1.37 per share. On the date of the funding of the initial tranche of the 15.00% Secured Debenture, the Company recorded the 15.00% Secured Debenture Warrant to equity at a fair value of $6.1 million. The 15.00% Secured Debenture Warrant was accounted for as permanent equity in accordance with ASC 815,Derivatives and Hedging (“ASC 815”), and was recorded at fair value at inception. The fair value of the warrant was determined using a Black-Scholes Option pricing model, with each scenario weighted based on the probability the warrant will become issuable.

The assumptions used to calculate the valuation of the 15.00% Secured Debenture Warrant as of May 5, 2025 were as follows:

The fair value per share of the 15.00% Secured Debenture Warrant as of May 5, 2025 was approximately $0.19.

During the year ended December 31, 2025, Yorkville exercised a portion of the 15.00% Secured Debenture Warrant for 26,500,000 shares of the Company’s common stock for net proceeds of $36.3 million. As of December 31, 2025, warrants to purchase an additional 5,000,000 shares of common stock remained outstanding under the 15.00% Secured Debenture Warrant.

March 2025 Offering

On March 20, 2025, the Company sold 46,500,000 shares of its common stock, Pre-Funded Warrants to purchase 138,930,464 shares of its common stock and the Common Warrants to purchase 185,430,464 shares of its common stock in a registered direct offering pursuant to an underwriting agreement with several underwriters for aggregate gross proceeds of $279.9 million with $11.9 million of underwriting discounts and $0.5 million of related issuance costs. The Company recorded the common stock, Pre-Funded Warrants and Common Warrants to equity at a fair value equal to the net proceeds of $267.5 million.

During the second quarter of 2025, all of the Pre-Funded Warrants were exercised for 138,930,464 shares of common stock at an exercise price of $0.001 per share for total proceeds of $0.1 million.

The Pre-Funded Warrants and Common Warrants were freestanding financial instruments that are legally detachable and separately exercisable from the shares of common stock with which they were issued, do not embody an obligation for the Company to repurchase its shares, and permit the holders to receive a fixed number of shares of common stock upon exercise.

Inducement of Common Warrant Exercise

As disclosed in Note 12, “Warrant Liabilities,” on October 8, 2025, the Company entered into a warrant exercise inducement agreement with the holder of the Common Warrants, whereby in consideration for exercising the 185,430,464 outstanding Common Warrants at the exercise price as set forth in the Common Warrants of$2.00 per share, the Company agreed to provide to the holder the$7.75 Warrants. In addition, under the warrant exercise inducement agreement, the holder was permitted to receive, upon exercise, in lieu of 154,430,464 common shares, the New Pre-Funded Warrants. As a result of the warrant exercise inducement transaction, the Company received net proceeds, after deducting$16.1 million of transaction expenses and fees, of$354.7 million and recorded a related inducement charge of$196.5 million to inducement of common warrant exercise in the consolidated statements of operations. Included within the inducement of common warrant exercise charge of$196.5 million was the fair value of the$7.75 Warrants of$180.4 million and$16.1 million of transaction expenses and fees incurred in connection with the warrant exercise inducement agreement.

During the fourth quarter of 2025, all of the New Pre-Funded Warrants were exercised for 154,430,464 shares of the Company’s common stock for proceeds of $15 thousand.

Share-Based Consideration Payable to a Customer

On August 24, 2022, the Company and Amazon.com, Inc. (“Amazon”) entered into a Transaction Agreement (the “2022 Transaction Agreement”), under which the Company concurrently issued to Amazon.com NV Investment Holdings LLC, a wholly owned subsidiary of Amazon, a warrant (the “Amazon Warrant”) to acquire up to 16,000,000 shares of the Company’s common stock (the “Amazon Warrant Shares”), subject to certain vesting events described below, as discussed in Note 18, “Share-Based Consideration Payable to a Customer.”

During 2017, warrants to purchase up to 110,573,392 shares of common stock were issued in connection with transaction agreements with Amazon and Walmart, as discussed in Note 18, “Share-Based Consideration Payable to a Customer.”

Accumulated Other Comprehensive Income/(Loss)

Accumulated other comprehensive income/(loss) is comprised of unrealized gains and losses on available-for-sale securities and foreign currency translation gains and losses. Amounts reclassified from accumulated other comprehensive income/(loss) was $5.0 million, $0 and $12.8 million for the years ended December 31, 2025, 2024 and 2023, respectively. The amount reclassified during the year ended December 31, 2025 was due to foreign currency translation effects associated with the sale of the Company’s interest in a non-consolidated entity. The amount reclassified during the year ended December 31, 2023 was due to realized loss on available-for-sale securities.

Net current-period other comprehensive income for the year ended December 31, 2025 increased due to foreign currency translation gains of $4.3 million. Net current-period other comprehensive income for the year ended December 31, 2024 increased due to foreign currency translation gains of $4.3 million. Net current-period other comprehensive income for the year ended December 31, 2023 increased due to unrealized gains on available-for-sale securities of $9.9 million, partially offset by foreign currency translation losses of $3.5 million.

Non-controlling Interest

Our consolidated financial statements include the accounts of majority-owned subsidiaries consolidated under the variable interest model. Non-controlling interest represent the portion of equity not attributable to Plug Power Inc. and are reported as a separate component of equity on our consolidated balance sheets. Net loss and comprehensive income/(loss) for majority-owned subsidiaries are attributed to Plug Power Inc. and to non-controlling interest holders on our consolidated statements of operations and consolidated statements of comprehensive loss based on respective ownership percentages. Refer to Note 28, “Variable Interest Entities,” for further information.

17. Revenue

Disaggregation of revenue

The following table provides information about disaggregation of revenue (in thousands):

Contract balances

Contract assets relate to contracts for which revenue is recognized on a straight-line basis, however billings escalate over the life of a contract. Contract assets also include amounts recognized as revenue in advance of billings to customers, which are dependent upon the satisfaction of another performance obligation. These amounts are included in contract assets on the consolidated balance sheets.

The deferred revenue and contract liabilities relate to the advance consideration received from customers for services that will be recognized over time (primarily fuel cell and related infrastructure services and electrolyzer systems and solutions). Deferred revenue and contract liabilities also include advance consideration received from customers prior to delivery of products. These amounts are included within deferred revenue and other contract liabilities on the consolidated balance sheets.

Significant changes in the contract assets and the deferred revenue and contract liabilities balances during the period are as follows (in thousands):

Estimated future revenue

The following table includes estimated revenue expected to be recognized in the future related to performance obligations that are unsatisfied (or partially unsatisfied) at the end of the reporting period, including provision for common stock warrants (in thousands):

18. Share-Based Consideration Payable to a Customer

Amazon Transaction Agreement in 2022

On August 24, 2022, the Company and Amazon entered into a Transaction Agreement (the “2022 Amazon Transaction Agreement”), under which the Company concurrently issued to Amazon.com NV Investment Holdings LLC, a wholly owned subsidiary of Amazon, a warrant (the “2022 Amazon Warrant”) to acquire up to 16,000,000 shares (the “2022 Amazon Warrant Shares”) of the Company’s common stock, subject to certain vesting events described below. The Company and Amazon entered into the 2022 Amazon Transaction Agreement in connection with a concurrent commercial arrangement under which Amazon agreed to purchase hydrogen fuel from the Company through August 24, 2029.

1,000,000 of the 2022 Amazon Warrant Shares vested immediately upon issuance of the 2022 Amazon Warrant.15,000,000 of the 2022 Amazon Warrant Shares will vest in multiple tranches over the 7-year term of the 2022 Amazon Warrant based on payments made to the Company directly by Amazon or its affiliates, or indirectly through third parties,

with 15,000,000 of the 2022 Amazon Warrant Shares fully vesting if Amazon-related payments of $2.1 billion are made in the aggregate. The exercise price for the first 9,000,000 2022 Amazon Warrant Shares is $22.9841 per share and the fair value on the grant date was $20.36. The exercise price for the remaining 7,000,000 2022 Amazon Warrant Shares will be an amount per share equal to 90% of the 30-day volume weighted average share price of the Company’s common stock as of the final vesting event that results in full vesting of the first 9,000,000 2022 Amazon Warrant Shares. The 2022 Amazon Warrant is exercisable through August 24, 2029.

Upon the consummation of certain change of control transactions (as defined in the 2022 Amazon Warrant) prior to the vesting of at least 60% of the aggregate 2022 Amazon Warrant Shares, the 2022 Amazon Warrant will automatically vest and become exercisable with respect to an additional number of 2022 Amazon Warrant Shares such that 60% of the aggregate 2022 Amazon Warrant Shares shall have vested. If a change of control transaction is consummated after the vesting of at least 60% of the aggregate 2022 Amazon Warrant Shares, then no acceleration of vesting will occur with respect to any of the unvested 2022 Amazon Warrant Shares as a result of the transaction. The exercise price and the 2022 Amazon Warrant Shares issuable upon exercise of the 2022 Amazon Warrant are subject to customary antidilution adjustments.

On August 24, 2022,1,000,000 of the 2022 Amazon Warrant Shares associated with tranche 1 vested. The warrant fair value associated with the vested shares of tranche 1 of $20.4 million was capitalized to contract assets based on the grant date fair value and is subsequently amortized ratably as a reduction to revenue based on the Company’s estimate of revenue over the term of the agreement. As of December 31, 2025, the balance of the contract asset related to tranche 1 was $15.1 million which is recorded in contract assets in the Company’s consolidated balance sheets. During the second quarter of 2023, all 1,000,000 of the Amazon Warrant Shares associated with tranche 2 vested. The warrant fair value associated with the vested shares of tranche 2 was $20.4 million and was determined on the grant date of August 24, 2022. As of December 31, 2025, the balance of the contract asset related to tranche 2 was $15.1 million. Tranche 3 will vest over the next $1.0 billion of collections from Amazon and its affiliates. The grant date fair value of tranche 3 will also be amortized ratably as a reduction to revenue based on the Company’s estimate of revenue over the term of the agreement. As of December 31, 2025, the balance of the contract asset related to tranche 3 was $1.9 million. Because the exercise price has yet to be determined, if probable of vesting, the fair value of tranche 4 will be remeasured at each reporting period end and amortized ratably as a reduction to revenue based on the Company’s estimate of revenue over the term of the agreement.

As of December 31, 2025 and 2024,3,500,000 and 3,000,000 of the 2022 Amazon Warrant Shares had vested, respectively, andnone of the 2022 Amazon Warrant Shares had been exercised. The total amount of provision for common stock warrants recorded as a reduction of revenue for the 2022 Amazon Warrant during the years ended December 31, 2025, 2024 and 2023 was $15.9 million, $19.0 million and $4.9 million, respectively.

Amazon Transaction Agreement in 2017

On April 4, 2017, the Company and Amazon entered into a Transaction Agreement (the “2017 Amazon Transaction Agreement”), pursuant to which the Company agreed to issue to Amazon.com NV Investment Holdings LLC, a warrant (the “2017 Amazon Warrant”) to acquire up to 55,286,696 shares (the “2017 Amazon Warrant Shares”) of the Company’s common stock, subject to certain vesting events. The Company and Amazon entered into the 2017 Amazon Transaction Agreement in connection with existing commercial agreements between the Company and Amazon with respect to the deployment of the Company’s GenKey fuel cell technology at Amazon distribution centers. The vesting of the 2017 Amazon Warrant Shares was conditioned upon payments made by Amazon or its affiliates (directly or indirectly through third parties) pursuant to the existing commercial agreements. On December 31, 2020, the Company waived the remaining vesting conditions under the 2017 Amazon Warrant, which resulted in the immediate vesting of all the third tranche of the 2017 Amazon Warrant Shares.

As of December 31, 2025 and 2024, all 55,286,696 of the 2017 Amazon Warrant Shares had vested and the 2017 Amazon Warrant was exercised with respect to 34,917,912 shares of the Company’s common stock. The total amount of provision for common stock warrants recorded as a reduction of revenue for the 2017 Amazon Warrant during the years ended December 31, 2025, 2024 and 2023 was $0.3 million, $0.4 million and $0.4 million, respectively.

Walmart Transaction Agreement

On July 20, 2017, the Company and Walmart entered into a Transaction Agreement (the “Walmart Transaction Agreement”), pursuant to which the Company agreed to issue to Walmart a warrant (the “Walmart Warrant”) to acquire up to 55,286,696 shares of the Company’s common stock, subject to certain vesting events (the “Walmart Warrant Shares”). The Company and Walmart entered into the Walmart Transaction Agreement in connection with existing commercial agreements between the Company and Walmart with respect to the deployment of the Company’s GenKey fuel cell technology across various Walmart distribution centers.

On December 30, 2025, the Company entered into an agreement with Walmart pursuant to which, upon the occurrence of certain specified events, the Company has agreed to grant Walmart a contingent, limited-use license to access and use certain escrowed GenKey System-related materials. Pursuant to the agreement, Walmart agreed to terminate the Walmart Transaction Agreement and to forfeit all vested portions of the Walmart Warrant. The unvested portions of the Walmart Warrant were cancelled and accordingly, no shares of common stock will become issuable by the Company in connection with the Walmart Warrant. As of December 30, 2025,13,094,217 shares of the Walmart Warrant Shares had been exercised,34,554,185 shares of the Walmart Warrant Shares had vested and were forfeited and 7,638,294 shares of the Walmart Warrant Shares remained unvested and were cancelled.

The total amount of provision for common stock warrants recorded as a reduction of revenue for the Walmart Warrant during the years ended December 31, 2025, 2024 and 2023 was $29.2 million, $19.6 million, and $5.9 million, respectively.

19. Employee Benefit Plans

2011 and 2021 Stock Option and Incentive Plan

On May 12, 2011, the Company’s stockholders approved the 2011 Stock Option and Incentive Plan (the “2011 Plan”). The 2011 Plan provided for the issuance of up to a maximum number of shares of common stock equal to the sum of (i)1,000,000, plus (ii) the number of shares of common stock underlying any grants pursuant to the 2011 Plan or the Plug Power Inc. 1999 Stock Option and Incentive Plan that are forfeited, canceled, repurchased or are terminated (other than by exercise). The shares were issued pursuant to stock options, stock appreciation rights, restricted stock awards and certain other equity-based awards granted to employees, directors and consultants of the Company. No further grants may be made under the 2011 Plan after May 12, 2021. In July 2021, the 2021 Stock Option Incentive Plan, as amended (the “2021 Plan”) was approved by the Company’s stockholders. The 2021 Plan provides for the issuance of up to a maximum number of shares of common stock equal to the sum of (i)22,500,000 shares, plus the 473,491 shares remaining under the 2011 Plan as of the effective date of that the 2021 Plan, plus (iii) shares underlying any awards under the 2021 Plan and the 2011 Plan that are forfeited, canceled, cash-settled or otherwise terminated, other than by exercise. In June 2023, the Company’s stockholders approved an increase in the number of shares of the Company’s common stock authorized for issuance under the 2021 Plan to 51,400,000. In July 2025, the Company’s stockholders approved an increase in the number of shares of the Company’s common stock authorized for issuance under the 2021 Plan to 91,400,000. Stock-based compensation costs recognized, excluding the Company’s matching contributions of $9.5 million, $11.0 million and $12.1 million, respectively, to the Plug Power Inc. 401(k) Savings & Retirement Plan and quarterly Board and executive compensation, were approximately $40.5 million, $70.3 million and $150.0 million for the years ended December 31, 2025, 2024 and 2023, respectively, in connection with the 2011 and 2021 Plans.

The components and classification of stock-based compensation expense, excluding the Company’s matching contributions to the Plug Power Inc. 401(k) Savings & Retirement Plan and quarterly Board compensation, were as follows (in thousands):

Option Awards

The Company issues options that become exercisable based on time and/or market conditions and are classified as equity awards.

Service Stock Options Awards

To date, service-based stock option awards (“Service Stock Options”) granted under the 2011 and 2021 Plans have vesting provisions ranging fromone tothree years in duration and expireten years after issuance. Service Stock Options for employees issued under these plans generally vest in equal annual installments over three years and expireten years after issuance. Service Stock Options granted to members of the Board generally vestone year after issuance. The Company estimates the fair value of the Service Stock Options using a Black-Scholes valuation model, and the resulting fair value is recorded as compensation cost on a straight-line basis over the option vesting period. Key inputs and assumptions used to estimate the fair value of the Service Stock Options include the grant price of the award, the expected option term, volatility of the Company’s stock, an appropriate risk-free rate, and the Company’s dividend yield. Estimates of fair value are not intended to predict actual future events or the value ultimately realized by employees who receive equity awards, and subsequent events are not indicative of the reasonableness of the original estimates of fair value made by the Company.

The assumptions made for purposes of estimating fair value under the Black-Scholes model for the 18,738,248,12,227,935 and 6,849,689 Service Stock Options granted during years ended December 31, 2025, 2024 and 2023, respectively, were as follows:

There wasno expected dividend yield for the Service Stock Options granted.

The estimated stock price volatility is derived from the Company’s actual historic stock prices over the expected term, which represents the Company’s best estimate of expected volatility.

The following table reflects the Service Stock Option activity for the year ended December 31, 2025:

The weighted average grant-date fair value of the Service Stock Options granted during the years ended December 31, 2025, 2024 and 2023 was $2.22, $1.63, and $4.88 per share, respectively. The total intrinsic fair value of Service Stock Options exercised during the years ended December 31, 2025, 2024 and 2023 was approximately $0.5 million, $0.1 million and $5.3 million. The total fair value of Service Stock Options that vested during the years ended December 31, 2025, 2024 and 2023 was $19.5 million, $26.0 million and $33.1 million, respectively.

Compensation cost associated with Service Stock Options represented approximately $19.4 million, $21.8 million, and $31.5 million of the total share-based payment expense recorded for the years ended December 31, 2025, 2024 and 2023, respectively. Additionally, as of December 31, 2025 there was approximately $52.9 million of unrecognized compensation cost related to Service Stock Options to be recognized over a weighted average remaining period of 2.33 years.

Market Condition Stock Option Awards

The Company grants market condition stock options awards under the 2021 plan to the Chief Executive Officer and certain other executive officers. These market condition stock options awards are subject to both market conditions, tied to the achievement of stock price hurdles, and time-based vesting; therefore, a Monte Carlo Simulation was utilized to determine the grant-date fair value with the associated expense recognized over the requisite service period. Up toone third (1/3) the market condition stock options awards will vest and become exercisable on each of the first three anniversaries of the grant date, provided that the volume weighted average price of the Company’s common stock during any 30 consecutive trading day period in thethree-year performance period following the grant date of the stock options (“VWAP”) equals or exceeds certain levels.

The Company didnot grant market condition stock options awards during the year ended December 31, 2025. The Company granted 2,952,500 and 6,405,000 market condition stock options awards during the years ended December 31, 2024 and 2023, respectively.

Failure to achieve any of the stock price hurdles applicable to a market condition stock options awards during thethree-year performance period will result in the applicable options not becoming exercisable. The market condition stock options awards have a maximum term ofseven toten years from the grant date.

Key inputs and assumptions used to estimate the fair value of market condition stock options awards include the grant price of the awards, the expected option term, VWAP hurdle rates, volatility of the Company’s stock, an appropriate risk-free rate, and the Company’s dividend yield. Estimates of fair value are not intended to predict actual future events or

the value ultimately realized by employees who receive equity awards, and subsequent events are not indicative of the reasonableness of the original estimates of fair value made by the Company.

The following table presents key assumptions used to estimate the fair value of the market condition stock options awards granted in 2024 and 2023:

The following table reflects the market condition stock options awards activity for the year ended December 31, 2025. Solely for the purposes of this table, the number of shares is based on participants earning the maximum number of shares underlying the market condition stock options awards (i.e.,200% of the target number of shares).

There wereno market condition stock options awards granted during the year ended December 31, 2025. The weighted average grant-date fair value of market condition stock options awards granted during the years ended December 31, 2024 and 2023 was $0.49 and $4.32, respectively. There wereno market condition stock options awards exercised during the years ended December 31, 2025, 2024 and 2023. The total fair value of the market condition stock options awards that vested during the years ended December 31, 2025, 2024 and 2023 was $4.8 million, $25.5 million and $20.8 million, respectively.

Compensation cost associated with market condition stock options awards represented approximately $2.2 million, $12.9 million and $64.0 million of the total share-based payment expense recorded for the years ended December 31, 2025, 2024 and 2023, respectively. Compensation costs associated with these awards are recognized as the requisite service period is rendered, regardless of when, if ever, the market condition is satisfied. Compensation cost for the year ended December 31, 2024 includes reversals due to forfeitures of unvested market condition stock options of during the first quarter of 2024. Forfeitures represent the expense related to awards for which the requisite service period was not met. The compensation expense reversals were offset by compensation costs of $25.1 million during the year ended December 31, 2024. As of December 31, 2025, there was approximately $0.9 million of unrecognized compensation cost related to market condition stock options awards to be recognized over a weighted average remaining period of 0.47 years.

As of December 31, 2025, there were 1,045,000 unvested shares underlying market condition stock options awards for which the employee requisite service period has not been rendered but are expected to vest. The aggregate

intrinsic value of these unvested market condition stock options awards was $0 as of December 31, 2025. The weighted average remaining contractual term of these unvested market condition stock options awards was 4.38 years as of December 31, 2025.

Restricted Stock and Restricted Stock Unit Awards

Restricted stock and restricted stock unit awards generally vest in equal installments over a period ofone tothree years. Restricted common stock and restricted stock unit awards are valued based on the closing price of the Company’s common stock on the date of grant, and compensation cost is recorded on a straight-line basis over the vesting period.

The following table reflects the restricted stock and restricted stock unit activity during the year ended December 31, 2025 (in thousands except share amounts):

The weighted average grant-date fair value of the restricted stock and restricted stock unit awards granted during the years ended December 31, 2025, 2024 and 2023, was $3.46, $2.21, and $11.55, respectively. The total fair value of restricted stock and restricted stock unit awards that vested during the years ended December 31, 2025, 2024 and 2023 was $25.2 million, $42.4 million, and $58.2 million, respectively.

The Company recorded expense associated with its restricted stock and restricted stock unit awards of approximately $19.0 million, $35.6 million, and $54.5 million during the years ended December 31, 2025, 2024 and 2023, respectively. Additionally, as of December 31, 2025 there was approximately $21.9 million of unrecognized compensation cost related to restricted stock and restricted stock unit awards to be recognized over a weighted average remaining period of 1.92 years.

Included in the total unvested restricted common stock and restricted stock units as of December 31, 2025, there were 250,000 restricted common stock units outstanding with a performance target. The Company recorded expense associated with the restricted common stock units with a performance target of $25 thousand during the year ended December 31, 2025. Additionally, as of December 31, 2025 there was $0.2 million of unrecognized compensation cost related to the restricted common stock units outstanding with a performance target to be recognized over the weighted average period of 0.58 years.

401(k) Savings & Retirement Plan

The Company offers a 401(k) Savings & Retirement Plan to eligible employees meeting certain age and service requirements. This plan permits participants to contribute 100% of their salary, up to the maximum allowable by the Internal Revenue Service regulations. Participants are immediately vested in their voluntary contributions plus actual earnings or less actual losses thereon. Participants are vested in the Company’s matching contribution based on years of service completed. Participants are fully vested upon completion ofthree years of service. The Company issued 6,315,659,4,314,747, and 1,473,662 shares of common stock pursuant to the Plug Power Inc. 401(k) Savings & Retirement Plan during the years ended December 31, 2025, 2024, and 2023, respectively.

The Company’s expense for this plan was approximately $9.5 million, $11.0 million, and $12.1 million for the years ended December 31, 2025, 2024, and 2023, respectively.

Non-Employee Director Compensation

Each non-employee director is paid an annual retainer for his or her service, in the form of either cash or stock compensation. This annual retainer is paid in four quarterly installments. The Company granted 426,433,295,090, and 59,323 shares of common stock to non-employee directors as compensation during the years ended December 31, 2025, 2024 and 2023, respectively. All common stock issued related to this annual retainer that is paid quarterly, is fully vested at the time of issuance and is valued at fair value on the date of issuance. The Company’s share-based compensation expense in connection with non-employee director quarterly compensation was approximately $0.7 million, $0.7 million and $0.5 million for the years ended December 31, 2025, 2024 and 2023, respectively.

In accordance with the non-employee director compensation plan, during the year ended December 31, 2025 the Company reimbursed $0.1 million of administrative expenses incurred by Mr. McNamee.

20. Restructuring

In March 2025, the Company announced initiatives to reduce its workforce, realign its manufacturing footprint and streamline its organization to enhance operational efficiency and improve overall liquidity (the “2025 Restructuring Plan”). We began executing the 2025 Restructuring Plan in March 2025 and it was effectively completed during the fourth quarter of 2025.

In February 2024, the Company announced a restructuring plan (the “2024 Restructuring Plan”). The 2024 Restructuring Plan included strategic moves to enhance our financial performance and ensure long-term value creation in a competitive market. We began executing the 2024 Restructuring Plan in February 2024 and it was effectively completed during the fourth quarter of 2024.

The determination of when we accrue for involuntary termination benefits under restructuring plans depends on whether the termination benefits are provided under an ongoing benefit arrangement or under a one-time benefit arrangement. We account for involuntary termination benefits that are provided pursuant to one-time benefit arrangements in accordance with ASC 420,Exit or Disposal Cost Obligations (“ASC 420”) whereas involuntary termination benefits that are part of an ongoing written or substantive plan are accounted for in accordance with ASC 712,Nonretirement Postemployment Benefits (“ASC 712”). We accrue a liability for termination benefits under ASC 420 in the period in which the plan is communicated to the employees and the plan is not expected to change significantly. For ongoing benefit arrangements, inclusive of statutory requirements, we accrue a liability for termination benefits under ASC 712 when the existing situation or set of circumstances indicates that an obligation has been incurred, it is probable the benefits will be paid, and the amount can be reasonably estimated. The restructuring charges that have been incurred but not yet paid are recorded in accrued expenses and other current liabilities in our consolidated balance sheets, as they are expected to be paid within the next twelve months.

During the years ended December 31, 2025 and 2024, the Company incurred $25.9 million and $8.2 million in restructuring costs, respectively, which were recorded in the restructuring financial statement line item in the consolidated statements of operations. The following table reflects the category of restructuring charges incurred during the years ended December 31, 2025 and 2024 (in thousands):

The accrued restructuring balances as of December 31, 2025 and 2024 were recorded in the accrued expenses financial statement line item in the consolidated balance sheets. Restructuring activities related to the 2025 and 2024 Restructuring Plans were as follows (in thousands):

As of December 31, 2025, total accrued expenses related to restructuring activities were comprised of (1) $0.8 million of employee severance and benefit arrangements and (2) $0.2 million of legal and professional services costs and are expected to be paid during the first quarter of 2026.

21. Impairment

During the fourth quarter of 2025, the Company determined that its previously forecasted sales and margin projections for 2025 were unlikely to be achieved. Additionally, during the fourth quarter of 2025, the Company conducted a strategic review of its product lines and updated future sales and related cash flow projections for certain product lines. As a result, cash flow projections for several of the Company’s asset groups were reduced during the fourth quarter of 2025, which indicated that the carrying amounts of certain long-lived assets (including property, plant, and equipment, equipment related to power purchase agreements and fuel delivered to customers, and right of use assets related to operating leases) and finite-lived intangible assets may not be recoverable. Additionally, during the third quarter of 2025 certain product lines experienced changes in their prospective sales pipelines, and the Company identified impairment of its long-lived assets and contract assets during its quarterly impairment analysis.

Asset groups are the unit of account for a long-lived asset or assets to be held and used which represent the lowest level for which identifiable cash flows are largely independent of other groups of assets and liabilities. The decrease in cash flow projections for several asset groups was largely attributed to several factors, including the Company failing to meet 2025 sales and margin projections as well as decreased future cash flow projections across certain product lines including stationary, liquefiers and fuel cells. Additionally, in November 2025, the Company announced that it has suspended activities associated with the Department of Energy loan program. This pause, as well as the decrease in cash flow projections, was primarily due to weakening demand in the global hydrogen market. As a result, the Company tested the recoverability of its long-lived assets and finite-lived intangibles by comparing the carrying values against undiscounted future cash flow projections and determined that an impairment existed.

During the fourth quarter of 2025, certain property, plant, and equipment were written down to their estimated fair values. The fair value for revenue generating assets was determined using a market approach utilizing prices for similar assets in active markets. The fair value for property, plant, and equipment was determined using a market approach, where available, and where not available, a cost approach. The fair value for equipment related to power purchase agreements and fuel delivered to customers was determined using a discounted cash flow income approach considering estimated market rent. The fair value for right of use assets related to operating leases was determined using a discounted cash flow income approach considering estimated market rent. The fair values for finite-lived intangible assets were determined using the income approach.

During the years ended December 31, 2025, 2024 and 2023, the Company recorded impairment charges of$783.5 million, $949.3 million and $269.5 million, respectively, to impairment in the consolidated statements of operations. The following table reflects the category of impairment charges recorded during the years ended December 31, 2025, 2024 and 2023 (in thousands):

To the extent there are further changes in market conditions or the performance of the Company’s long-lived assets, there is a possibility that the Company could incur additional impairment charges in the future.

22. Income Taxes

The components of loss before income taxes and the income tax (expense)/benefit for the years ended December 31, 2025, 2024, and 2023, by jurisdiction, are as follows (in thousands):

The significant components of current and deferred income tax expense/(benefit) for the years ended December 31, 2025, 2024, and 2023, by jurisdiction, are as follows (in thousands):

The Company’s effective income tax rate differed from the federal statutory rate as follows (in thousands, except for effective income tax rate):

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of certain assets and liabilities for financial reporting and the amounts used for income tax purposes. The Company has recorded a net deferred tax asset in non-current other assets as of December 31, 2025 and 2024 of approximately $13 thousand and $19 thousand, respectively. Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2025 and 2024 are as follows (in thousands):

The Company has recorded a valuation allowance, as a result of uncertainties related to the realization of its net deferred tax asset, at December 31, 2025 and 2024 of approximately$1.4 billion and $1.1 billion, respectively. A reconciliation of the current year change in valuation allowance is as follows (in thousands):

The Company made cash payments related to tax, net of refunds, by the following jurisdictions (in thousands):

Income taxes paid, net of refunds, are material in the following jurisdictions (in thousands):

The Company has not changed its overall conclusion with respect to the need for a valuation allowance against its net deferred tax assets in the U.S., which remain fully reserved. Except for a few service entities mainly in Europe, all deferred tax assets are offset by a full valuation allowance because it is more likely than not that the tax benefits of the net operating loss carryforwards and other deferred tax assets will not be realized. As of December 31, 2025, the Company’s Netherlands subsidiary maintains a full valuation allowance on its deferred tax assets that will not be realized.

Under Section 382 of the Internal Revenue Code of 1986, as amended (the “Code”), the use of loss carryforwards may be limited if a change in ownership of a company occurs. If it is determined that due to transactions involving the Company’s shares owned by its 5 percent or greater stockholders a change of ownership has occurred under the provisions of Section 382 of the Code, the Company’s federal and state NOL carryforwards could be subject to significant Section 382 limitations.

The Company’s deferred tax assets include $3.8 billion of U.S. net operating loss carryforwards. The NOL carryforwards available as of December 31, 2025 include $3.6 billion of NOL that was generated in 2018 through 2025 that do not expire. The remainder, if unused, will expire at various dates from 2033 through 2037. Based on analysis of stock transactions, an ownership change as defined under Section 382 of the Code occurred in 2013, which imposes a $13.5 million limit on the utilization of pre-change losses that can be used to offset taxable income in future years. The pre-change NOL carryforwards will expire, if unused, at various dates from 2026 through 2033. The Company continuously analyzes stock transactions and has determined that no ownership changes have occurred since 2013 that would further limit the utilization of NOLs. Therefore, NOLs of $3.8 billion incurred in post-change years are not subject to limitation.

As of December 31, 2025, $25.9 million of research credit carryforwards generated after the most recent IRC Section 382 ownership change are included in the Company’s deferred tax assets. Due to limitations under IRC Section 382, research credit carryforwards existing prior to the most recent IRC Section 382 ownership change will not be used and are not reflected in the Company’s gross deferred tax asset as of December 31, 2025. The remaining credit carryforwards will expire during the periods 2033 through 2043.

As of December 31, 2025, the Company has unused Canadian net operating loss carryforwards of approximately $4.4 million. The net operating loss carryforwards, if unused, will expire at various dates between 2041 through 2045.

As of December 31, 2025, the Company has unused French net operating loss carryforwards of $133.3 million. The net operating loss may carry forward indefinitely or until the Company changes its activity.

As of December 31, 2025, the Company has unused Netherlands net operating loss carryforwards of $47.4 million. The net operating loss may carry forward indefinitely or until the Company changes its activity.

As of December 31, 2025, the Company hasno un-repatriated foreign earnings or unrecognized tax benefits.

On July 4, 2025, the OBBBA was enacted into law. The OBBBA includes permanent extensions of certain provisions of the Tax Cuts and Jobs Act of 2017, modifies various federal clean energy tax provisions of the IRA and includes the allowance of immediate expensing of qualifying research and development expenses incurred in the United States. The most significant impacts of the OBBBA to the Company are related to Section 45V Credit for Production of Clean Hydrogen, which will be available for clean hydrogen facilities that begin construction before January 1, 2028 and the Section 48E Investment Tax Credit which provides for a fixed 30% investment tax credit for “qualified fuel cell property” that begins construction after December 31, 2025, subject to the phase-out provisions applicable to Section 48E. As of December 31, 2025, management concluded the OBBBA’s effects were not material to the Company's income tax expense based on the Company’s facts and circumstances as of that date.

The Company files income tax returns in the U.S. federal jurisdiction and various state and foreign jurisdictions. In the normal course of business, the Company is subject to examination by taxing authorities. Open tax years in the U.S. range from 2022 and forward. Open tax years in the foreign jurisdictions range from 2012 and forward. However, upon examination in subsequent years, if net operating losses carryforwards and tax credit carryforwards are utilized, the US and foreign jurisdictions can reduce net operating loss carryforwards and tax credit carryforwards utilized in the year being examined if they do not agree with the carryforward amount. As of December 31, 2025, the Company is not under audit in the U.S. or any other non-U.S. taxing jurisdictions.

The Organization for Economic Co-operation and Development Inclusive Framework on Base Erosion and Profit Shifting established a global minimum corporate tax rate of 15% on multi-national corporations, commonly referred to as the Pillar Two rules, which have been agreed upon in principle by over 140 countries. While the United States has not adopted the Pillar Two rules, numerous foreign countries have enacted legislation to implement the Pillar Two rules, effective January 1, 2024, or are expected to enact similar legislation. As of December 31, 2025, the Company did not meet the consolidated revenue threshold and is not subject to the OECD Global Anti-Base Erosion (“GloBE”) Model Rules under Pillar Two. The Company will continue to monitor the implementation of such rules in the jurisdictions in which it operates.

23. Earnings Per Share

Basic earnings per common stock are computed by dividing net loss by the weighted average number of common stock outstanding during the reporting period. In periods when we have net income, the shares of our common stock subject to the convertible notes outstanding during the period will be included in our diluted earnings per share under the if-converted method. Since the Company is in a net loss position for all periods presented, all potentially dilutive securities are considered anti-dilutive and are therefore excluded from the calculation of diluted earnings per share in accordance with ASC 260,Earnings Per Share.

The following table provides the components of the calculations of basic and diluted earnings per share (in thousands, except share amounts):

As of December 31, 2025, 2024 and 2023, the Company had potentially dilutive securities outstanding, consisting of stock options, restricted stock units, warrants and other equity instruments, representing shares of common stock totaling 432,551,889,233,331,656 and 163,726,275, respectively, on an as-converted basis.

24. Segment and Geographic Area Reporting

Our organization is managed from a sales perspective based on “go-to-market” sales channels, emphasizing shared learning across end-user applications and common supplier/vendor relationships. These sales channels are structured to serve a range of customers for our products and services. As a result of this structure, we concluded that we haveone operating and reportable segment – the design, development and sale of hydrogen products and solutions that help customers meet their business goals while decarbonizing their operations. Our Chief Executive Officer was identified as the chief operating decision maker (“CODM”). All significant operating decisions made by management are based upon analysis of Plug on a total company basis, including assessments related to our incentive compensation plans. The accounting policies of the segment are the same as those described in the summary of significant accounting policies.

The information regularly provided to the CODM used to assess performance and allocate resources is the same as the Company’s consolidated financial statements. The measure of segment profit or loss used by the CODM in assessing segment performance and how to allocate resources is consolidated net loss which is presented in the consolidated statements of operations. The CODM uses net loss in strategic planning, for example, decision making of whether to allocate resources towards strengthening sales channels, investing in research and development, focusing on cost-down initiatives, and/or analyzing company overhead in respect to specific products and service lines. Net loss is also used to monitor budget versus actual results and is considered in assessments related to company-wide incentive compensation. The significant segment expenses included within the segment measure of profit or loss are total costs of revenue, research and development, selling, general and administrative, and impairment. Other segment items are comprised of restructuring, change in fair value of contingent consideration, interest income, interest expense, other income/(expense), net, realized loss on investments, net, change in fair value of equity securities, loss on extinguishment of convertible debt instruments and debt, change in fair value of convertible debt instruments and debt, inducement of common warrant exercise, change in fair value of warrant liabilities, loss on equity method investments, income tax (expense)/benefit and net loss attributable to non-controlling interest, which are presented in the consolidated statements of operations. The CODM is not regularly provided a measure of segment assets.

The following table presents reported segment revenue, significant segment expenses, other segment items and segment measure of profit/(loss):

The revenue and long-lived assets based on geographic location are as follows (in thousands):

25. Commitments and Contingencies

Restricted Cash

In connection with certain of the noted sale/leaseback agreements, cash of $352.3 million and $476.2 million, respectively, was required to be restricted as security as of December 31, 2025 and 2024, which will be released over the lease term. As of December 31, 2025 and 2024, the Company also had certain letters of credit and bank guarantees backed by security deposits totaling $193.1 million and $285.1 million, respectively, of which $159.6 million and $242.7 million are security for the above noted sale/leaseback agreements, respectively, and $33.5 million and $42.4 million are customs related letters of credit and bank guarantees, respectively.

As of December 31, 2025 and 2024, the Company had $80.0 million and $73.7 million, respectively, held in escrow related to the construction of certain hydrogen production plants.

Litigation

Legal matters are handled in the ordinary course of business. The outcome of any such matters, regardless of the merits, is inherently uncertain; therefore, assessing the likelihood of loss and any estimated damages is difficult and subject to considerable judgment. Liabilities for loss contingencies arising from claims, assessments, litigation, fines, and penalties and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably

estimated. Legal costs incurred in connection with loss contingencies are expensed as incurred. While we are not in a position to accurately predict the outcome of any legal or other proceedings, where there is at least a reasonable possibility that a loss may be incurred, GAAP requires us to disclose an estimate of the reasonably possible loss or range of loss, if material, or make a statement that such an estimate cannot be made. Except for below, a reasonably possible loss or range of loss associated with any individual legal proceeding cannot be currently estimated.

Securities Litigation and Related Stockholder Derivative Litigation

2023 Securities Action and Related Derivative Litigation

A consolidated action is pending in the United States District Court for the District of Delaware asserting claims under the federal securities laws against the Company and certain of its senior officers on behalf of a putative class of purchasers of the Company’s securities, styledIn re Plug Power, Inc. Securities Litigation, No. 1:23-cv-00576-MN (the “2023 Securities Action”). The plaintiffs filed a consolidated complaint on September 28, 2023, in which they assert claims under the federal securities laws against the Company and four of its senior officers, Mr. Marsh, Mr. Middleton, Sanjay Shrestha, and former officer David Mindnich, on behalf of a putative class of purchasers of the Company’s common stock between January 19, 2022 and March 1, 2023. The complaint alleges that the defendants made “materially false and/or misleading statements” about the Company’s business and operations, including the Company’s revenue goals for 2022, its ability to effectively manage its supply chain and product manufacturing, and its progress in construction of new hydrogen production capacity. On February 4, 2025, the Court issued an opinion and order dismissing the consolidated complaint, with leave to replead. The plaintiffs filed an amended complaint on February 25, 2025, in which they no longer name Mr. Mindnich. Defendants filed a motion to dismiss the second amended complaint on April 30, 2025, and briefing was completed on July 23, 2025.

Beginning on September 13, 2023, three separate actions were filed in the U.S. District Court for the District of Delaware and in the U.S. District Court for the Southern District of New York asserting claims derivatively, on behalf of the Company, against certain former and current Company officers and directors based on the allegations and claims in the 2023 Securities Action. Those cases have been consolidated in the District of Delaware under the captionIn re Plug Power, Inc. Stockholder Deriv. Litig., No. 1:23-cv-01007-MN (D. Del.). The defendants named in the constituent complaint were Mr. Marsh, Mr. Middleton, Mr. Mindnich, Martin Hull, Ms. Helmer, Mr. Kenausis, Mr. McNamee, Mr. Schneider, Mr. Silver, Mr. Willis, and current or former directors Jean Bua, Kavita Mahtani, and Kyungyeol Song. In an order entered on April 26, 2024, the Court approved the parties’ stipulation to stay all proceedings until motions to dismiss have been resolved in the 2023 Securities Action.

2024 Securities Litigation

On March 22, 2024, Ete Adote filed a complaint in the United States District Court for the Northern District of New York asserting claims under the federal securities laws against the Company, Mr. Marsh, and Mr. Middleton, on behalf of an alleged class of purchasers of the Company’s common stock between May 9, 2023 and January 16, 2024, styledAdote v. Plug Power, Inc. et al., No. 1:24-cv-00406-MAD-DJS (N.D.N.Y.). The complaint alleges that the defendants made misstatements concerning the Company’s progress in construction of new hydrogen production capacity and its ability to effectively manage its supply chain. On April 30, 2024, a second complaint asserting substantially similar claims against the same defendants, but on behalf of a putative class of purchasers of the Company’s common stock between March 1, 2023 and January 16, 2024, was filed in the Northern District of New York, styledLee v. Plug Power, et al., No. 1:24;cv-0598-MAD-DJS (N.D.N.Y.). On November 25, 2024, the magistrate judge issued an order consolidating the two cases and appointing lead plaintiffs. Lead plaintiff filed a consolidated complaint on August 25, 2025. All defendants filed motions to dismiss the complaint, and briefing was completed on December 23, 2025.

Other Litigation

On October 23, 2024, a case entitledFirst Solar, Inc. v. Plug Power Inc., Index No. 655610/2024 was filed in the New York State Supreme Court, New York County, asserting a claim for breach of contract associated with a purchase order for solar panels manufactured by First Solar to be purchased by the Company. The complaint seeks monetary relief along with pre-judgment interest. On December 22, 2025, First Solar moved for summary judgment, which has been fully

briefed and is pending oral argument. As of December 31, 2025, the Company recorded an accrual related to ongoing litigation costs.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to credit risk consist principally of cash, cash equivalents, restricted cash, accounts receivable and marketable securities. Cash and restricted cash are maintained in accounts with financial institutions which, at times, may exceed the Federal depository insurance coverage of $250 thousand. The Company has not experienced losses on these accounts and management believes, based upon the quality of the financial institutions, that the credit risk with regard to these deposits is not significant.

Concentrations of credit risk with respect to receivables exist due to the limited number of select customers with whom the Company has initial commercial sales arrangements. To mitigate credit risk, the Company performs appropriate evaluation of a prospective customer’s financial condition.

As of December 31, 2025, one customer individually exceeded 10% of total consolidated accounts receivable with a balance of $48.9 million, or 36.3%, of the Company’s consolidated accounts receivable. As of December 31, 2024, one customer individually exceeded 10% of total consolidated accounts receivable with a balance of $38.5 million, or 24.5%, of the Company’s consolidated accounts receivable.

For the year ended December 31, 2025, two customers individually exceeded 10% of total consolidated revenues. One customer accounted for $171.8 million, or 24.2%, andone customer accounted for $101.7 million, or 14.3%, of total consolidated revenues. For the year ended December 31, 2024, two customers individually exceeded 10% of total consolidated revenues. One customer accounted for $104.6 million, or 16.6%, andone customer accounted for $90.9 million, or 14.4%, of total consolidated revenues. For the year ended December 31, 2023, two customers individually exceeded 10% of total consolidated revenues. One customer accounted for $209.0 million, or 23.4%, andone customer accounted for $97.0 million, or 10.9%, of total consolidated revenues.

Unconditional Purchase Obligations

The Company has entered into certain off–balance sheet commitments that require the future purchase of goods or services (“unconditional purchase obligations”). The Company’s unconditional purchase obligations primarily consist of supplier arrangements, take or pay contracts and service agreements. For certain vendors, the Company’s unconditional obligation to purchase a minimum quantity of raw materials at an agreed upon price is fixed and determinable; while certain other raw material costs will vary due to product forecasting and future economic conditions.

Future payments under non-cancelable unconditional purchase obligations with a remaining term in excess of one year as of December 31, 2025, were as follows (in thousands):

During 2025, the Company finalized the renegotiation of a supplier arrangement that previously contained minimum purchase requirements which resulted in the Company recording a charge of $40.3 million in selling, general and administrative expenses in the consolidated statements of operations. As of December 31, 2025, the Company made payments of$13.1 million and had a remaining liability of$27.2 million which was recorded in contingent consideration, loss accrual for service contracts, and other current liabilities.

26. Related Party Transactions

SK Plug Hyverse

As disclosed in Note 7, “Investments,” on December 31, 2025, the Company executed the Share Purchase Agreement with SK Innovations to sell its full 49% common stock ownership in SK Plug Hyverse. SK Plug Hyverse was our 49/51 joint venture that aimed to provide hydrogen fuel cell systems, hydrogen fueling stations, electrolyzers and clean hydrogen to the Korean and other selected Asian markets. For the years ended December 31, 2025, 2024 and 2023, we recognized related party revenue of $0, $6.4 million and $2.3 million, respectively, associated with SK Plug Hyverse. As of December 31, 2025 and 2024, we had related party outstanding accounts receivable of $0 and $3.5 million, respectively.

HyVia

On December 10, 2024, HyVia announced that it entered into receivership proceedings opened by judgment of the Commercial Court of Versailles. On February 18, 2025, HyVia entered into a judicial liquidation proceeding opened by judgment of the Economic Activities Court of Versailles (judgment publication being still pending). HyVia was our 50/50 joint venture that manufactured and sold fuel cell powered electric light commercial vehicles (“FCE-LCVs”) and supplied hydrogen fuel and fueling stations to support the FCE-LCV market, in each case primarily in Europe. For the years ended December 31, 2025, 2024 and 2023, we recognized related party revenue of $0, $5.0 million and $13.9 million, respectively, associated with HyVia. As of December 31, 2025 and 2024, we hadno related party outstanding accounts receivable.

27. Government Assistance

Government assistance whose primary condition is the purchase, construction, or acquisition of a long-lived asset are considered asset-based assistance and are recognized as a reduction to such asset’s cost-basis, which reduces future depreciation. The Company recorded a reduction in its property, plant and equipment balance in the consolidated balance sheets in the amount of $1.7 million and $0 during the years ended December 31, 2025 and 2024, respectively. Other government assistance not related to long-lived assets are considered income-based assistance, which are recognized as a reduction to the research and development expense financial statement line item in the consolidated statements of operations in the amounts of $6.9 million, $1.8 million and $0 during the years ended December 31, 2025, 2024 and 2023, respectively.

On January 16, 2025, Plug Power Energy Loan Borrower LLC, a wholly owned indirect subsidiary of the Company, finalized a loan guarantee of up to $1.66 billion with the U.S. Department of Energy (the “DOE”) through the DOE’s Loan Program Office to finance the development, construction, and ownership of up tosix green hydrogen production facilities. On November 7, 2025, the Company announced that it suspended activities related to the DOE loan program. As a result, the Company recorded a charge to its capitalized closing fees related to DOE loan guarantee of $13.2 million during the year ended December 31, 2025 to selling, general and administrative expenses in the consolidated statements of operations.

In August 2022, the IRA was enacted into law and is effective for taxable years beginning after December 31, 2022. The IRA contains numerous credits and incentives that are relevant to the Company including: (i) a new Section 45V Credit for Production of Clean Hydrogen, which provides a lean hydrogen production tax credit (“PTC”) of up to $3 per kg of qualified clean hydrogen over a 10-year credit period for the production of qualified clean hydrogen at a qualified facility in the United States; (ii) an extension and amendment of the Section 48 Investment Tax Credit (“ITC”) for Qualified Fuel Cell Properties, including fuel cell technology; (iii) a new Section 48 Investment Tax Credit for Energy Storage Technologies, which expands the applicability of the investment tax credit to include standalone energy storage projects, among other things; and (iv) a new Section 48E Clean Electricity Investment Tax Credit, which provides a tax credit for investment in facilities that generate clean electricity, among other provisions.

Section 45V Credit for Production of Clean Hydrogen

In 2024, the Company determined that it qualifies for the clean hydrogen PTC resulting from operation of the Company’s hydrogen production plant located in Georgia. The Company has chosen elective pay, also referred to as direct pay, which makes the PTC refundable as the Company can receive the full value of the credit from the Internal Revenue Service. This election will apply to the 2024 taxable year and thefour subsequent taxable years unless revoked.

For the year ended December 31, 2025 the Company recognized PTC of $7.1 million as a reduction to the fuel delivered to customers and related equipment costs of revenue financial statement line item in the consolidated statements of operations and $7.7 million as an increase to the other assets financial statement line item in the consolidated balance sheets. For the year ended December 31, 2024 the Company recognized PTC of $4.0 million as a reduction to the fuel delivered to customers and related equipment costs of revenue financial statement line item in the consolidated statements of operations and $4.5 million as an increase to the other assets financial statement line item in the consolidated balance sheets.

Section 48 Investment Tax Credit for Qualified Fuel Cell Properties of Energy Storage Technologies

In 2024, the Company determined that it qualified for the Section 48 ITC for Qualified Fuel Cell Properties of Energy Storage Technologies related to its hydrogen storage and liquefaction assets. A base rate credit of 6% is available to qualified energy storage property in the year that it is placed in-service, with availability of increased credit rates if the property qualifies. The Company determined that it qualified for a rate credit of 30%. As the ITC is considered a transferable tax credit, the Company accounts for it as a grant related to assets. Therefore, the ITC will be recognized as a reduction to its hydrogen storage and liquefaction assets cost-basis, recognized within the property, plant, and equipment, net financial statement line item of the consolidated balance sheets, which will reduce future depreciation over the next 30 years. The amount of the ITC, which was recognized in the prepaid expenses, tax credits, and other current assets financial statement line item of the consolidated balance sheets as of December 31, 2025 and 2024, was $0 and $31.3 million, respectively.

28. Variable Interest Entities

Hidrogenii

Our wholly-owned subsidiary, Plug Power LA JV, LLC, created a joint venture with Niloco Hydrogen Holdings LLC, a wholly-owned subsidiary of Olin, named “Hidrogenii” in the third quarter of 2022. We believe Hidrogenii will support reliability of supply and speed to market for hydrogen throughout North America and set the foundation for broader collaboration between Plug and Olin. Hidrogenii began the construction of a 15-ton-per-day hydrogen plant in St. Gabriel, Louisiana. Hidrogenii is owned 50% by Plug Power LA JV, LLC and 50% by Niloco Hydrogen Holdings LLC.

The Company has determined Hidrogenii to be a VIE, and the Company is considered to be the VIE’s primary beneficiary, as we determined we have both the power to direct the activities that most significantly impact the economic performance of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. On an ongoing basis, we are contractually obligated to certain operational capital funding. We consolidate the joint venture’s results within our single consolidated reportable segment. Hidrogenii has similar risks to those described in Item 1A, “Risk Factors,” in this Annual Report on Form 10-K.

The table below summarizes balances associated with Hidrogenii as reflected on our consolidated balance sheets as of December 31, 2025 (in thousands). The VIE’s assets can be used to settle only the VIE’s obligations and the creditors related to the VIE’s liabilities have no recourse against the general credit of the Company:

29. Subsequent Events

Amendment to Increase Authorized Shares of Common Stock

On February 12, 2026, the Company’s stockholders approved an amendment to the Company’s amended and restated certificate of incorporation, as amended, to increase the number of authorized shares of the Company’s common stock from 1,500,000,000 shares to 3,000,000,000 shares. The amendment became effective February 12, 2026 upon its filing with the Secretary of State of the State of Delaware.

Infrastructure Optimization Initiative

On February 24, 2026, the Company entered into a definitive agreement with Stream US Data Centers, LLC pursuant to which the Company agreed to sell certain real property and related assets located in the Town of Alabama, Genesee County, New York. The Company will be entitled to receive a purchase price ranging between $132.5 million and $142.0 million, depending on the timing of closing and the removal status of certain hydrogen storage spheres located on the property. The transaction is expected to close on or before June 30, 2026, subject to closing conditions.

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: March 2, 2026