Hyliion Holdings Corp.

NOTES TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

(Dollar amounts in thousands, except as separately indicated)

Note 1. Overview

Hyliion Holdings Corp. is a Delaware corporation headquartered in Cedar Park, Texas, with research and development (“R&D”) facilities in Cincinnati, Ohio, that designs and develops the KARNOTM Power Module for stationary and mobile applications and provides R&D services. References to the “Company,” “Hyliion,” “we,” “our,” or “us” in this report refer to Hyliion Holdings Corp. and its wholly owned subsidiary, unless expressly indicated or the context otherwise requires.

The KARNO Power Module is a complete, fully integrated, enclosed, fuel agnostic power generating solution, including balance of plant such as cooling system, controls, fuel handling, and air handling systems, that generates electricity on command in stationary power generation applications powered by KARNO Cores. The KARNO Core is a linear generator that generates its own heat, and converts thermal energy generated from oxidization of fuels into electrical energy. It uses linear electric motors in a four-shaft system to generate electricity via a flameless oxidation process, achieving near zero emissions without emissions treatment systems.

Note 2. Disposals

On November 7, 2023, the Board of the Company approved a strategic plan to wind down its powertrain business and preserve the related intellectual property (the “Plan”). As part of the Plan, the Company will continue to focus on commercialization of its KARNO Power Module technology. We have not accounted for the impacts of the Plan as a discontinued operation through September 30, 2025 as we have not abandoned or sold the underlying intellectual property and continue wind down activities. We expect to complete wind down activities in the fourth quarter of fiscal year 2025.

Total charges and (benefits) expenses related to the Plan of$(0.1) million and $(0.9) million for the three months ended September 30, 2025 and 2024, respectively, and$1.0 million and $2.9 million for the nine months ended September 30, 2025 and 2024, respectively, inclusive of recoveries from assets sold and charges to assets held for sale discussed below, are included inexit and termination costs in the condensed consolidated statements of operations. The change in total liabilities associated with the Plan is included within accrued expenses and other current liabilities as presented in Note 9, and accounts payable, and is summarized as follows (in millions):

NOTES TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

(Dollar amounts in thousands, except as separately indicated)

The above estimates of the cash expenditures and charges that the Company expects to incur in connection with the Plan, and the timing thereof, are subject to a number of assumptions and actual amounts may differ materially from estimates. In addition, the Company may incur other cash expenditures or charges not currently contemplated due to unanticipated events.

Assets Held for Sale

Certain assets of our powertrain business, including Class 8 semi-trucks and capital equipment, continue to be actively marketed for sale, and we are actively locating buyers for these assets. At the time of initial classification as held for sale at March 31, 2024, we estimated that the sale of these assets was expected to be completed within one year and it was unlikely that significant changes to the plan of sale would be made. Due to increased uncertainty regarding the timing of the disposition, driven by deteriorating market conditions in the electric vehicle industry, we reclassified assets previously recorded as held for sale totaling $1.0 million to property and equipment, net, on the condensed consolidated balance sheets, and recognized charges of $1.6 million during the three months ended March 31, 2025.

We had assets held for sale ofnil and $2.6 million consisting of property and equipment in connection with the Plan at their fair value less costs to sell on the condensed consolidated balance sheets at September 30, 2025 and December 31, 2024, respectively. We used fair value hierarchy Level III inputs including comparable assets, adjusted for condition, and recorded charges ofnil, for the three months ended September 30, 2025 and 2024, respectively, and $1.6 million and $5.6 million for the nine months ended September 30, 2025 and 2024, respectively, included in exit and termination costs in the condensed consolidated statements of operations.

We recorded net benefits for recoveries related to asset sales of $0.4 million and $0.9 million for the three months ended September 30, 2025 and 2024, respectively, and $1.0 million and $2.1 million for the nine months ended September 30, 2025 and 2024, respectively, included in exit and termination costs in the condensed consolidated statements of operations and in gain on disposal of assets, including assets held for sale in the condensed consolidated statements of cash flows.

Note 3. Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

The accompanying condensed consolidated financial statements include the accounts of Hyliion Holdings Corp. and its wholly owned subsidiary. Intercompany transactions and balances have been eliminated upon consolidation. The condensed consolidated financial statements and accompanying notes have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and in accordance with the rules and regulations of the United States Securities and Exchange Commission (“SEC”), which permit reduced disclosure for interim periods. The condensed consolidated balance sheet at December 31, 2024 was derived from audited financial statements for the fiscal year then ended, but does not include all necessary disclosures required with respect to annual financial statements. In the opinion of the

Company, these condensed consolidated financial statements include all recurring adjustments and normal accruals necessary for a fair presentation of the Company’s financial position, results of operations and cash flows for the dates and periods presented. These condensed consolidated financial statements and accompanying notes should be read in conjunction with the Company’s 2024 Annual Report. Results for interim periods are not necessarily indicative of the results to be expected for a full fiscal year or for any future period.

These condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and settlement of liabilities in the normal course of business. The Company is an early-stage growth company and has generated negative cash flows from operating activities since inception. At September 30, 2025, the Company had total equity of $203.9 million, inclusive of cash and cash equivalents of $17.9 million and total investments of $146.9 million. Based on this, the Company has sufficient funds to continue to execute its business strategy for the next twelve months from the issuance date of the financial statements included in this Quarterly Report on Form 10-Q.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the balance sheet date, as well as reported amounts of expenses during the reporting period. The Company’s most significant estimates and judgments involve assets held for sale, income taxes and valuation of share-based compensation. Management bases its estimates on historical experience and on various other assumptions believed to be reasonable, the results of which form the basis for making judgments about the carrying values of assets and liabilities. Actual results could differ from those estimates, and such differences could be material to the Company’s condensed consolidated financial statements.

Segment Information

ASC 280, Segment Reporting, defines operating segments as components of an enterprise where discrete financial information is available that is evaluated regularly by the chief operating decision-maker (“CODM”) in deciding how to allocate resources and in assessing performance. The Company operates as a single operating segment from which all revenue and net income (loss) is derived and for which all assets are attributed. The Company’s CODM is the chief executive officer, who has ultimate responsibility for the operating performance of the Company and the allocation of resources. The CODM uses net income (loss) to manage the business and does not segment the business for internal reporting or decision making.

The significant expense categories and amounts that are regularly provided to the CODM and included in the reported measure of segment loss for the three and nine months ended September 30, 2025 and 2024 are summarized as follows (in millions):

Concentration of Supplier Risk

The Company is dependent on certain suppliers, many of which are single source suppliers, and the inability of these suppliers to deliver necessary components of the Company’s products in a timely manner at prices, quality levels and volumes that are acceptable, or the Company’s inability to efficiently manage these components from these suppliers, could have a material adverse effect on the Company’s business, prospects, financial condition and operating results.

Cash and Cash Equivalents

The Company considers all highly liquid investments with a maturity date of 90 days or less at the time of purchase to be cash and cash equivalents only if in checking, savings or money market accounts. Cash and cash equivalents include cash held in banks and money market accounts and are carried at cost, which approximates fair value. The Company maintains cash in excess of federally insured limits at financial institutions, which it believes are of high credit quality, and has not incurred any losses related to these balances to date. The Company believes its credit risk, with respect to these financial institutions, to be minimal.

Restricted Cash

The Company has provided its corporate headquarters lessor with a letter of credit for $0.7 million to secure the performance of the Company’s lease obligations, backed by a restricted cash deposit to pay any draws on the letter of credit by the lessor. Total cash and cash equivalents and restricted cash as presented in the condensed consolidated statements of cash flows is summarized as follows:

Accounts Receivable

Accounts receivable are stated at a gross invoice amount, net of an allowance for doubtful accounts. The allowance for doubtful accounts is maintained at a level considered adequate to provide for potential account losses on the balance based on the Company’s evaluation of the anticipated impact of current economic conditions, changes in the character and size of the balance, past and expected future loss experience and other pertinent factors. At September 30, 2025 and December 31, 2024, accounts receivable included amounts receivable from customers of $0.6 million and $1.5 million, respectively. At September 30, 2025 and December 31, 2024, there wasno allowance for doubtful accounts on customer receivables.

Investments

The Company’s investments consist of corporate bonds, U.S. treasury and agency securities, state and local municipal bonds and commercial paper, all of which are classified as held-to-maturity, with a maturity date of 36-months or less at the time of purchase. The Company determines the appropriate classification of investments at the time of purchase and re-evaluates such designation as of each balance sheet date. Investments are classified as held-to-maturity when the Company has the positive intent and ability to hold the securities to maturity. Held-to-maturity securities are stated at amortized cost, adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization, along with interest, is included in interest income. The Company uses the specific identification method to determine the cost basis of securities sold.

Investments are impaired when a decline in fair value is judged to be other-than-temporary. The Company evaluates investments for impairment by considering the length of time and extent to which market value has been less than cost or amortized cost, the financial condition and near-term prospects of the issuer as well as specific events or circumstances that may influence the operations of the issuer and the Company’s intent to sell the security or the likelihood that it will be required to sell the security before recovery of the entire amortized cost. Once a decline in fair value is determined to be other-than-temporary, an impairment charge is recorded to other income and a new cost basis in the investment is established.

Fair Value Measurements

ASC 820, Fair Value Measurements, clarifies that fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based upon assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, ASC 820 establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

Level I: Quoted prices (unadjusted) for identical assets or liabilities in active markets that the Company can access at the measurement date;

Level II: Significant other observable inputs other than level I prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data; and

Level III: Significant unobservable inputs that reflect the Company’s own assumptions about the assumptions that market participants would use in pricing an asset or liability.

An asset’s or liability’s fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation techniques used need to maximize the use of observable inputs and minimize the use of unobservable inputs.

The Company believes its valuation methods are appropriate and consistent with other market participants, however the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date.

The Company’s financial instruments consist of cash and cash equivalents and restricted cash, accounts receivable, investments, accounts payable and accrued expenses. The carrying value of cash and cash equivalents and restricted cash, accounts receivable, accounts payable and accrued expenses approximate fair value because of the short-term nature of those instruments. The fair value of investments is based on quoted prices for identical or similar instruments in markets that are not active. As a result, investments are classified within Level II of the fair value hierarchy.

Inventories

As of September 30, 2025, the KARNO Power Module has not yet been commercialized. Costs incurred for components acquired prior to our determination of reaching a commercial stage are expensed as R&D costs, resulting in zero cost basis for those components. As a result, moving-average prices for inventory that is capitalized in future periods may be significantly affected by those zero cost items. Inventory is consumed in the performance of contracts for R&D services in the quarter in which it is purchased, including certain allocations of overhead costs, and we therefore do not record inventory at each reporting period pertaining to these contracts.

Revenue

The Company follows five steps to recognize revenue from contracts with customers under ASC 606, Revenue from Contracts with Customers, which are:

•Step 1: Identify the contract(s) with a customer;

•Step 2: Identify the performance obligations in the contract;

•Step 3: Determine the transaction price;

•Step 4: Allocate the transaction price to the performance obligations in the contract; and

•Step 5: Recognize revenue when (or as) a performance obligation is satisfied.

U.S. Government Contracts

The Company was performing undertwo contracts as both a prime and subcontractor to the United States government to provide R&D services. The larger of thesetwo contracts was modified and accounted for as a new contract in the quarter ending December 31, 2024. These contracts were not accounted for as revenue prior to September 30, 2024 as they were not in the ordinary course of business and the counterparties were not customers under GAAP. In September 2024, the Company was awarded a best effort cost-plus-fixed fee contract, modified in March 2025, up to $16.0 million by the United States Department of the Navy’s Office of Naval Research (“ONR”) to research the suitability of its KARNO Power Module for Navy ships and stationary power generation applications. Under the agreement, the Company will provide R&D services through September 2026, including delivery of up toseven KARNO Cores. The ONR contract represented a significant change in business strategy toward providing R&D activities in the ordinary course of business in addition to developing Power Modules for stationary and mobile applications. In July 2025, the Company was awarded a Phase II best effort cost-plus-fixed fee contract up to $1.5 million by the ONR to demonstrate the conceptual feasibility of the Phase I effort and show development progress towards successful application. Under the agreement, the Company will provide R&D services through July 2026 with an option to extend through July 2027, including design reviews, simulations, and reporting.

The Company began accounting for these contracts under ASC 606 beginning in the quarter ending December 31, 2024. The remaining amounts of revenue that we may recognize under these contracts was up to $14.4 million as of September 30, 2025, which is expected to primarily be recognized in 2025 and 2026. There is a single research and development services performance obligation in each of these contracts that is measured over time as the services are performed. The Company generally invoices monthly, which corresponds directly with the value to the customers of the performance completed to date, and recognizes revenue in the amount that it has a right to invoice. Payment is ordinarily due within 90 days of invoice submission. Cost of R&D services revenue includes labor, allocated fringe and overhead, and inventory.

All revenue in the three and nine months ended September 30, 2025 and 2024 was recognized over time. The portion of our revenues from significant customers is summarized as follows and is attributable to the U.S.:

Research and Development Expense

R&D costs did not meet the requirements to be recognized as an asset as the associated future benefits were at best uncertain and there was no alternative future use at the time the costs were incurred. R&D costs include, but are not limited to, outsourced engineering services, allocated facilities costs, depreciation on equipment utilized in R&D activities, internal engineering and development expenses, materials, internally-developed software and employee-related expenses (including salaries, benefits, travel, and share-based compensation) related to development of the Company’s products and services.

Recent Accounting Pronouncements

In September 2025, the FASB issued ASU 2025-06, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40)-Targeted Improvements to the Accounting for Internal-Use Software, to modernize the accounting for software costs that are accounted for under Subtopic 350-40, Intangibles—Goodwill and Other—Internal-Use Software. The pronouncement is effective for fiscal years beginning after December 15, 2027 and interim periods within that fiscal year. We are currently evaluating the impact of adoption.

In July 2025, the FASB issued ASU 2025-05, Financial Instruments—Credit Losses (Topic 326)-Measurement of Credit Losses for Accounts Receivable and Contract Assets, to address challenges encountered when applying the guidance in Topic 326, Financial Instruments—Credit Losses, to current accounts receivable and current contract assets arising from transactions accounted for under Topic 606, Revenue from Contracts with Customers. The pronouncement is effective for fiscal years beginning after December 15, 2025 and interim periods within that fiscal year. We expect to adopt this ASU in the period ended March 31, 2026, applying the practical expedient policy election that assumes that current conditions as of the balance sheet date do not change for the remaining life of the current accounts receivable asset expected credit losses estimate on a prospective basis.

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40), and clarified by ASU 2025-01, to enable investors to better understand the major components of an entity’s income statement. The pronouncement is effective for fiscal years beginning after December 15, 2026 and interim periods beginning after December 15, 2027 and we expect a material impact to our disclosures as a result of adoption.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740), to enhance transparency and decision usefulness of income tax disclosures. The pronouncement is effective for fiscal years beginning after December 15, 2024 and we expect an impact to our disclosures as a result of adoption.

Note 4. Investments

The amortized cost, unrealized gains and losses, fair value and maturities of our held-to-maturity investments at September 30, 2025 and December 31, 2024 are summarized as follows:

Note 5. Fair Value Measurements

The fair value measurements of our financial assets at September 30, 2025 and December 31, 2024 are summarized as follows:

Note 6. Leases

In February 2025, the Company executed a sublease for a portion of its corporate office through April 2027. The components of lease operating income which are primarily included as reductions to R&D and selling, general and administrative expensein the condensed consolidated statements of operations for the three and nine months ended September 30, 2025 and 2024 are summarized as follows:

Note 7. Property and Equipment, Net

Property and equipment, net at September 30, 2025 and December 31, 2024 is summarized as follows:

Note 8. Share-Based Compensation

During the nine months ended September 30, 2025 and 2024, the Company granted 4.4 million and 6.1 million, respectively, restricted stock units which will vest over a period ofone tothree years. During the nine months ended September 30, 2025 and 2024,0.1 million and 1.2 million, respectively, of restricted stock units and options were forfeited. Share-based compensation expense for the three and nine months ended September 30, 2025 was $1.4 million and $4.1 million, respectively. Share-based compensation expense for the three and nine months ended September 30, 2024 was $1.1 million and $3.5 million, respectively.

Of the restricted stock units granted in the nine months ended September 30, 2025,2.7 million units may vest between February 18, 2026 and December 31, 2027 contingent upon achieving underlying closing stock price thresholds. These awards were valued at $1.46 per unit using fair value hierarchy Level III inputs including an underlying share volatility of 90% and a risk-free rate of 4.23%.

Note 9. Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities at September 30, 2025 and December 31, 2024 are summarized as follows:

Note 10. Commitments and Contingencies

Economic Incentive Agreement

During the quarter ended March 31, 2024, in connection with our operations in Cedar Park, Texas, the Company entered into an agreement with the Cedar Park Economic Development Corporation (“EDC”) that superseded prior agreements, whereby the Company would receive cash grants up to $1.1 million from the EDC at various measurement dates during the term of the agreement contingent upon the Company fulfilling and maintaining certain occupancy, investment, and employment requirements. The requirements must be met on or before specific measurement dates and maintained throughout the term of the agreement, which expires effective December 31, 2029. The Company has received payments to date of $0.4 million which are refundable as applicable performance requirements were not met and are included within accrued expenses and other current liabilities at September 30, 2025. Under the agreement, the EDC has the right to file a security interest to all assets of the Company.

Legal Proceedings

The Company is periodically involved in legal proceedings, legal actions and claims arising in the normal course of business, including proceedings relating to product liability, intellectual property, safety and health, employment and other matters. The Company believes that the outcome of such legal proceedings, legal actions and claims will not have a significant adverse effect on the Company’s financial position, results of operations or cash flows.

Note 11. Net Loss Per Share

The computation of basic and diluted net loss per share for the three and nine months ended September 30, 2025 and 2024 is summarized as follows (in thousands, except share and per share data):

Potential common shares excluded from the computation of diluted net loss per share because including them would have had an anti-dilutive effect for the three and nine months ended September 30, 2025 and 2024 are summarized as follows: