Ribbon Communications Inc

(1) NATURE OF THE BUSINESS

Ribbon Communications Inc. (“Ribbon” or the “Company”) is a leading global provider of communications technology to service providers and enterprises. The Company provides a broad range of software and high-performance hardware products, network solutions, and services that enable the secure delivery of data and voice communications, and high-bandwidth networking and connectivity for residential consumers and for small, medium, and large enterprises and industry verticals such as finance, education, government, utilities, and transportation. Ribbon’s mission is to create a recognized global technology leader providing cloud-centric solutions that enable the secure exchange of information, with unparalleled scale, performance, and elasticity. The Company is headquartered in Plano, Texas, and has a global presence with research and development, or sales and support locations in over thirty countries around the world.

(2) BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Basis of Presentation

The consolidated financial statements have been prepared in United States dollars, in accordance with accounting principles generally accepted in the United States (“GAAP”).

Private Placement Offering

On March 28, 2023, the Company issued 55,000 shares of newly designated Series A Preferred Stock (the “Preferred Stock”) to investors in a private placement offering at a price of $970 per share, along with 4.9 million warrants (the “Warrants”) to purchase shares of the Company’s common stock, par value $0.0001 per share (the “Private Placement”), at the exercise price of $3.77 per share. The proceeds from the Private Placement were approximately $53.4 million, including approximately $10 million from existing related party stockholders (See Note 16).

Equity Offering

On August 12, 2022, the Company entered into a Securities Purchase Agreement with certain investors for the sale (the “Equity Offering”) in a private placement by the Company of 17,071,311 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share, at a price of $3.05 per share. The aggregate gross proceeds from the Equity Offering were approximately $52.1 million, including $10.0 million from existing related party shareholders, before deducting offering expenses paid by the Company of approximately $1.7 million.

The original issuance of the Shares in the Equity Offering was exempt from the registration requirements of the Securities Act of 1933, as amended (the “Securities Act”). The Company subsequently filed a registration statement on Form S-3 (the “Registration Statement”) with the SEC registering the Shares, which Registration Statement was declared effective by the SEC on September 23, 2022.

Operating Segments

The Company’s chief operating decision maker (the “CODM”) is its president and chief executive officer. The CODM assesses the Company’s performance based on the performance oftwo separate organizations within Ribbon: the Cloud and Edge segment (“Cloud and Edge”) and the IP Optical Networks segment (“IP Optical Networks”).

Significant Accounting Policies

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of Ribbon and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.

Use of Estimates and Judgments

The preparation of financial statements in conformity with GAAP requires 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 financial statements and the reported amounts of revenue and expenses during the reporting periods. Significant estimates and judgments relied upon in preparing these consolidated financial statements include accounting for business combinations, revenue recognition for arrangements that contain multiple performance obligations, inventory valuations, assumptions used to determine the fair value of stock-based compensation and the Preferred Stock and Warrants, intangible asset and goodwill valuations, including impairments, debentures and warrants, warranty accruals, legal contingencies and recoverability of Ribbon’s net deferred tax assets and the related valuation allowances. Ribbon regularly assesses these estimates and records changes in estimates in the period in which they become known. Ribbon bases its estimates on historical experience and various other assumptions that it believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Reclassifications

Certain reclassifications, not affecting previously reported net income (loss), have been made to the previously issued financial statements to conform to the current year presentation.

Business Combinations

The Company recognizes identifiable assets acquired and liabilities assumed at their acquisition date fair values. Goodwill as of the acquisition date is measured as the excess of consideration transferred over the net of the acquisition date fair values of the assets acquired and the liabilities assumed and represents the expected future economic benefits arising from other assets acquired in the business combination that are not individually identified and separately recognized. While the Company uses its best estimates and assumptions as part of the purchase price allocation process to accurately value assets acquired and liabilities assumed at the acquisition date, its estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up toone year from the acquisition date, the Company records adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill to the extent that it identifies adjustments to the preliminary purchase price allocation. Upon the conclusion of the measurement period or final determination of the values of assets acquired and liabilities assumed, whichever comes first, any subsequent adjustments are recorded to the consolidated statements of operations.

Revenue Recognition

The Company derives revenue fromtwo primary sources: products and services. Product revenue includes: 1) the Company’s proprietary hardware and software that function together to deliver the products’ essential functionality and 2) the Company’s software only solutions that can be used on either the Company’s hardware or third-party hardware. Both proprietary hardware and software only solutions are also sold on a standalone basis.

Services include customer support (software updates, upgrades and technical support), consulting, design services, installation services and training. Generally, contracts with customers contain multiple performance obligations, consisting of products and services. For these contracts, the Company accounts for individual performance obligations separately if they are considered distinct.

When an arrangement contains more than one performance obligation, the Company will allocate the transaction price to each performance obligation on a relative standalone selling price basis. The Company utilizes the observable price of goods and services, including when they are sold separately to similar customers, in order to estimate standalone selling price (“SSP”).

The Company’s software licenses typically provide a perpetual right to use the Company’s software. However, the Company also sells term-based software licenses that expire and Software-as-a-Service (“SaaS”)-based software which are referred to as subscription arrangements. The Company does not customize its software nor are installation services required, as the customer has a right to utilize internal resources or a third-party service company. The software and

hardware are delivered before related services are provided and are functional without professional services or customer support. The Company has concluded that its software licenses are functional intellectual property that are distinct, as the user can benefit from the software on its own.

Product revenue from sales of the Company’s perpetual and term-based software licenses is typically recognized when the software is made available for download, as this is the point the user of the software can direct the use of and obtain substantially all of the remaining benefits from the functional intellectual property. The Company begins to recognize software revenue related to the renewal of term-based software licenses at the start of the renewal period. Revenue related to sales of SaaS-based software is recognized ratably over the service period as the customer does not take possession of the software or have the ability to take possession of the software.

The Company offers warranties on its products. Certain of the Company’s warranties are considered to be assurance-type in nature, ensuring the product is functioning as intended. Assurance-type warranties do not represent separate performance obligations. The Company also sells separately-priced maintenance service contracts which qualify as service-type warranties and represent separate performance obligations. The Company does not allow and has no history of accepting product returns.

Service revenue includes revenue from customer support and other professional services. Customer support includes software updates on a when-and-if-available basis, telephone support, integrated web-based support and bug fixes or patches. The Company sells its customer support contracts at a percentage of list or net product price. Customer support revenue is recognized ratably over the term of the customer support agreement, which is typicallyone year.

The Company’s professional services include consulting, technical support, resident engineer services, design services and installation services. Because control transfers over time, revenue is recognized based on progress toward completion of the performance obligation. The method to measure progress toward completion requires judgment and is based on the nature of the products or services to be provided.

The Company generally uses the input method to measure progress for its contracts and to recognize revenue because it believes such method, in general, best depicts the transfer of assets to its customers. The input method measures costs the Company has incurred in the period for its contracts. In some infrequent instances, the Company may engage a third-party to perform services on its behalf and in those cases the output method is used to recognize revenue because it best depicts the transfer of assets to its customers. Under the output method, there is a cost-to-cost measure of progress. The progress toward completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. When the measure of progress is based upon expended labor, progress toward completion is measured as the ratio of labor time expended to date versus the total estimated labor time required to complete the performance obligation. Revenue is recorded proportionally as costs are incurred or as labor is expended. Costs to fulfill these obligations can include internal labor as well as subcontractor costs.

Customer training includes courses offered by the Company. The related revenue is typically recognized as the training services are performed, typically over a period ofone tofive days.

Payment terms for the Company’s contracts with its customers typically range from 30 to 60 days from the invoice date. In certain cases, it may offer extended payment terms, which are assessed on a case-by-case basis.

The Company does not generally offer significant financing components in its contracts with customers. However, if a contract includes a significant financing component, the transaction price is adjusted for the time value of money. For the year ended December 31, 2024, the impact of financing components was immaterial.

Amounts billed to customers for sales and other taxes are excluded from the transaction price. Revenue is recognized net of any taxes collected from customers, which are subsequently remitted to government authorities.

Preferred Stock and Warrants

The Company accounted for the Preferred Stock until it was redeemed on June 25, 2024 and continues to account for the Warrants as liability-classified instruments based on an assessment of their specific terms in accordance with ASC Topic 480,Distinguishing Liabilities from Equity. The fair value option was elected for the Preferred Stock, as the Company considered fair value to best reflect the expected future economic value. These liabilities are remeasured to fair value at each reporting date using the same valuation methodology applied upon issuance using current input assumptions. The Preferred Stock was considered to be debt for our Consolidated Net Leverage Ratio covenant calculation required under our 2020 Credit Facility.

The value of the Preferred Stock was calculated using the Black-Derman-Toy (BDT) stochastic yield lattice model to capture the optimal timing of repayment, increasing dividend rate and other features, and the value of the Warrants is calculated using the Black-Scholes Pricing Model.

Changes in the fair value of the Preferred Stock and Warrants are reported as Other expense, net in the Company’s consolidated statements of operations.

Financial Instruments

The carrying amounts of the Company’s cash equivalents, accounts receivable, accounts payable and borrowings under a revolving credit facility in the Consolidated Balance Sheets approximates fair value due to the immediate or short-term nature of these financial instruments. Ribbon’s term debt balance as of December 31, 2024 and 2023 of $348.3 million and $235.4 million, respectively, had a fair value of approximately $350.4 million and $235.1 million, respectively. Our Warrants liabilities as of December 31, 2024 had a fair value of $8.1 million. Our Preferred Stock and Warrants liabilities as of December 31, 2023 had a combined fair value of $58.6 million, including cumulative dividends on the Preferred Stock of $3.9 million.

Financial instruments with remaining maturities or that are due within one year from the balance sheet date are classified as current. Financial instruments with maturities or that are payable more than one year from the balance sheet date are classified as noncurrent.

Fair Value Option - Investment in AVCT

The Company received debentures (the “Debentures”) and warrants (the “AVCT Warrants”) as sale consideration in connection with its December 1, 2020 sale of the Kandy Communications Business to American Virtual Cloud Technologies, Inc. (“AVCT”) (the “Kandy Sale”). On September 8, 2021 (the “Debenture Conversion Date”), the Debentures were converted into 13,700,421 shares of AVCT common stock (the “Debenture Shares”). In connection with the conversion of the Debentures to the Debenture Shares, the Company elected to use the fair value option to account for its equity investment in AVCT as permitted under Accounting Standards Codification (“ASC”) 825,Financial Instruments (“ASC 825”), which then refers to ASC 820,Fair Value Measurement (“ASC 820”) to provide the fair value framework for valuing such investments. In accordance with ASC 820, the Company recorded the investment in AVCT at fair value, with changes in fair value recorded as a component of Other (expense) income, net, in the consolidated statements of operations. See Note 4 for a discussion of the valuation of the Debentures, AVCT warrants and Debenture Shares.

On August 29, 2022, the Company and AVCT entered into a settlement agreement which provided for, amongst other things, the cancellation of the Company’s investment in the Debenture Shares and the AVCT Warrants with an aggregate fair value of $2.6 million. See Note 4 for a description of the settlement agreement with AVCT.

Transfers of Financial Assets

The Company’s IP Optical Networks segment maintains customer receivables factoring agreements with a number of financial institutions. Under the terms of these agreements, the Company may transfer receivables to the financial institutions, on a non-recourse basis, provided that the financial institutions approve the receivables in advance. The

Company maintains credit insurance policies from major insurance providers or obtains letters of credit from the customers for a majority of its factored trade receivables. The Company accounts for the factoring of its financial assets as a sale of the assets and records the factoring fees, when incurred, as a component of interest expense in the consolidated statements of operations, and the proceeds from the sales of receivables are included in cash from operating activities in the consolidated statements of cash flows.

Factoring of accounts receivable and associated fees for the years ended December 31, 2024 and 2023 were as follows (in thousands):

Foreign Currency Translation

For foreign subsidiaries where the functional currency is the local currency, assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during each period. Translation adjustments for these subsidiaries are included in Accumulated other comprehensive income.

For foreign subsidiaries where the functional currency is the U.S. dollar, monetary assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Nonmonetary assets and liabilities are remeasured into U.S. dollars at historical exchange rates. Revenue and expense items are translated at average rates of exchange prevailing during each period. Translation adjustments for these subsidiaries are included in Other expense, net.

Realized and unrealized foreign currency exchange gains and losses arising from transactions denominated in currencies other than the subsidiary’s functional currency are reflected in earnings.

The Company records its foreign currency (gains) losses as a component of Other expense, net. The Company recognized net foreign currency (gains) and losses of $5.7 million, less than $(0.1) million and $1.6 million for the years ended December 31, 2024, 2023 and 2022, respectively.

Inventory

Inventory is recorded at the lower of cost or market value using the first-in, first-out convention. The Company reduces the carrying value of inventory for those items that are potentially excess, obsolete or slow-moving based on changes in customer demand, technology developments or other economic factors.

Ribbon writes down evaluation equipment (equipment at customer sites for testing and evaluation) at the time of shipment to its customers, as it is probable that the inventory value will not be realized.

Deferred product costs represent deferred cost of revenue for product shipments to customers prior to satisfaction of Ribbon’s revenue recognition criteria. The Company classifies inventory that is not expected to be consumed within one year from the balance sheet date as noncurrent and includes such inventory as a component of Other assets.

Property and Equipment

Property and equipment are stated at cost, net of accumulated depreciation. Expenditures for maintenance and repairs are charged to expense as incurred. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets, which range fromtwo tofive years. Leasehold improvements are amortized over the

lesser of the lease term orfive years. When an asset is sold or retired, the cost and related accumulated depreciation or amortization are eliminated, and the resulting gain or loss, if any, is recognized in Loss from operations in the consolidated statement of operations. The Company reviews property and equipment for impairment in the same manner as intangible assets discussed below.

Software development costs associated with internal use software are incurred in three stages of development: the preliminary project stage, the application development stage and the post-implementation stage. Costs incurred during the preliminary project and post-implementation stages are expensed as incurred. Certain qualifying costs incurred during the application development stage are capitalized as property and equipment. Internal use software is amortized on a straight-line basis over its estimated useful life ofthree years, beginning when the software is ready for its intended use.

Intangible Assets and Goodwill

The Company’s intangible assets are comprised of in-process research and development, developed technology, customer relationships, trade names, and internal use software. Intangible assets are reviewed for impairment when events or changes in circumstances indicate that their carrying amounts may not be recoverable based upon the estimated undiscounted cash flows. Recoverability of intangible assets with estimated lives and other long-lived assets is measured by a comparison of the carrying amount of an asset or asset group to future net undiscounted cash flows expected to be generated by the asset or asset group. If these comparisons indicate that an asset is not recoverable, the Company will recognize an impairment loss for the amount by which the carrying value of the asset or asset group exceeds the related estimated fair value. Estimated fair value is based on either discounted future operating cash flows or appraised values, depending on the nature of the asset. The Company amortizes its intangible assets over their respective useful lives, with the exception of in-process research and development, which has an indefinite life until the product is generally available, at which time such asset is typically reclassified to developed technology, and the Company begins to amortize this asset. See Note 10 for additional information regarding the Company’s intangible assets.

Goodwill is recorded when the consideration for an acquisition exceeds the fair value of net tangible and identifiable intangible assets acquired. Goodwill is not amortized, but instead is tested for impairment at least annually, or more frequently if indicators of potential impairment exist, by comparing the fair value of the Company’s reporting unit to its carrying value.

The Company’s annual test for impairment of goodwill is completed as of October 1. For the purpose of testing goodwill for impairment, all goodwill is assigned to a reporting unit, which may either be an operating segment or a portion of an operating segment. The Company’s reporting units are itstwo operating segments, Cloud and Edge and IP Optical Networks. The Company performs a fair value analysis for each reporting unit using both an income and market approach, which encompasses a discounted cash flow analysis and a guideline public company analysis using selected multiples. The Company assesses each valuation methodology based upon the relevance and availability of the data at the time the valuation is performed and the methodologies are weighted appropriately. Any impairment charges are reported separately in the Company’s consolidated statements of operations.

Stock-Based Compensation

The Company’s stock-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense over the requisite service period, which generally represents the vesting period, and includes an estimate of the awards that will be forfeited.

The Company uses the Black-Scholes valuation model for estimating the fair value of stock options on the grant date. The fair value of stock option awards is affected by the Company’s stock price as well as valuation assumptions, including the volatility of Ribbon’s stock price, expected term of the option, risk-free interest rate and expected dividends.

The Company may grant to certain of its executives and certain other employees performance-based stock units (“PSUs”) that include a market condition. The Company uses a Monte Carlo simulation approach to model future stock

price movements based upon the risk-free rate of return, the volatility of each entity and the pair-wise covariance between each entity. These results are then used to calculate the grant date fair values of the PSUs. The Company is required to record expense for the PSUs with market conditions through their respective final vesting dates regardless of the number of shares that are ultimately earned. Once the grant date criteria have been met for a fiscal year performance period, the Company records stock-based compensation expense based on its assessment of the probability that the respective performance condition will be achieved and the level, if any, of such achievement. The Compensation Committee determines the number of shares earned, if any, after the Company’s financial results for each fiscal year performance period are finalized. Upon the determination by the Compensation Committee of the number of shares that will be received upon vesting, such number of shares becomes fixed and the unamortized expense is recorded through the remainder of the service period, at which time any Performance PSUs earned will vest pending each employee’s continuing employment with Ribbon through that date.

Concentration of Risk

Ribbon is subject to counterparty risk as well as financial instrument concentration risk involving cash, cash equivalents and accounts receivable. To mitigate these risks, cash and cash equivalents are diversified and maintained with various financial institutions globally. In certain instances, advance payments, credit insurance, or customer issued letters of credit are required to mitigate potential risk.

Certain components and software licenses from third parties used in Ribbon’s products are procured from single sources of supply. The failure of a supplier, including a subcontractor, to deliver on schedule could delay or interrupt Ribbon’s delivery of products and thereby materially adversely affect Ribbon’s revenue and operating results.

Advertising Costs

Advertising costs are expensed as incurred and included as a component of Sales and marketing expense in the Company’s consolidated statements of operations. Advertising expenses were $1.7 million, $1.2 million and $1.5 million for the years ended December 31, 2024, 2023 and 2022, respectively.

Loss Contingencies and Reserves

Ribbon is subject to ongoing business risks arising in the ordinary course of business, including legal claims, that affect the estimation process of the carrying value of assets, the recording of liabilities and the possibility of various loss contingencies. An estimated loss contingency is accrued when it is probable that a liability has been incurred or an asset has been impaired and the amount of loss can be reasonably estimated. Ribbon regularly evaluates current information available to determine whether such amounts should be adjusted and records changes in estimates in the period they become known.

An allowance for doubtful accounts is estimated based on the Company’s assessment of the collectability of specific customer accounts.

Ribbon accrues for royalties for technology that it licenses from vendors based on established royalty rates and usage. Ribbon is periodically contacted by third parties who claim that Ribbon’s products infringe on certain intellectual property of a third party. Ribbon evaluates these claims and accrues amounts when it is probable that the obligation has been incurred and the amounts are reasonably estimable.

Warranty

The Company records warranty liabilities for estimated costs of fulfilling its obligations under standard limited hardware and software warranties at the time of sale. The specific warranty terms and conditions vary depending upon the country in which the Company does business, but generally includes material costs, technical support, labor and associated overhead over a period ranging fromone tothree years. At December 31, 2024, the Company’s liability for product warranties was $12.3 million of which $5.2 million was current and included in Accrued expenses and other and $7.1 million was long-term and included in Other long-term liabilities in the Company’s consolidated balance sheet. At

December 31, 2023, the Company’s liability for product warranties was $12.2 million, of which $5.4 million was current and included in Accrued expenses and other, and $6.8 million was long-term and included in Other long-term liabilities in the Company’s consolidated balance sheet.

Research and Development Grants

The Company records grants received from the Office of the Innovation Authority of the Israeli Ministry of Economics (the “IIA”) as a reduction to Research and development expense. Royalties payable to the IIA are recognized pursuant to sales of related products and services and are included in Cost of revenue (see Note 26).

Accounting for Leases

The Company accounts for its leases in accordance with Accounting Standards Codification (“ASC”) 842,Leases (“ASC 842”) (see Note 21). The Company has operating leases for corporate offices, and research and development facilities. Operating leases are reported separately in the Company’s consolidated balance sheets at December 31, 2024 and 2023. The Company has no finance leases as of December 31, 2024 or 2023.

The Company determines if an arrangement is a lease at inception. A contract is determined to contain a lease component if the arrangement provides the Company with a right to control the use of an identified asset. Lease agreements may include lease and non-lease components. In such instances for all classes of underlying assets, the Company does not separate lease and non-lease components but rather, accounts for the entire arrangement under leasing guidance. Leases with an initial term of 12 months or less are not recorded on the balance sheet and lease expense for these leases is recognized on a straight-line basis over the lease term.

Lease expense for minimum fixed lease payments is recognized on a straight-line basis over the lease term. The expense for finance leases would include both interest and amortization expense components, with the interest component calculated based on the effective interest method and the amortization component calculated based on straight-line amortization of the right-of-use asset over the lease term. Lease contracts may contain variable lease costs, such as common area maintenance, utilities and tax reimbursements that vary over the term of the contract. Variable lease costs are not included in minimum fixed lease payments and as a result, are excluded from the measurement of the right-of-use assets and lease liabilities. The Company expenses all variable lease costs as incurred.

Accounting for Income Taxes

Deferred tax assets and liabilities are recognized for the expected future consequences of events that have been reflected in the consolidated financial statements. Deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities and operating loss carryforwards, using tax rates expected to be in effect for the years in which the differences are expected to reverse. The Company records valuation allowances to reduce deferred income tax assets to the amount that is more likely than not to be realized.

The Company has provided for income taxes on the undistributed earnings of its non-U.S. subsidiaries as of December 31, 2024, excluding Ireland and Israel, which are indefinitely reinvested. Accordingly, the Company is required to recognize and record deferred taxes for 2024 on the entire outside basis differences related to the foreign subsidiaries, the largest of these differences being undistributed earnings.

The Company determines whether it is more likely than not that a tax position will be sustained upon examination. If it is not more likely than not that a position will be sustained, no amount of the benefit attributable to the position is recognized. The tax benefit to be recognized of any tax position that meets the more likely than not recognition threshold is calculated as the largest amount that is more than 50% likely of being realized upon resolution of the contingency. The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes.

Defined Benefit Plans

The Company has defined benefit plans for some of its employees at various international locations. The Company recognizes retirement benefit assets or liabilities in the consolidated balance sheets reflecting the funded status of pension and other retirement benefit plans. Retirement benefit assets and liabilities are adjusted for the difference between the benefit obligations and the plan assets at fair value (measured at year-end), with the offset recorded directly to stockholders’ equity through Other comprehensive income (loss), net of tax. The amount recorded in stockholders’ equity represents the after-tax unamortized actuarial gains or losses, unamortized transition obligations and unamortized prior service costs.

Recent Accounting Pronouncements

In November 2024, the Financial Accounting Standards Board (the "FASB") issued ASU 2024-03,Income Statement, Reporting Comprehensive Income: Expense Disaggregation Disclosures (Subtopic 220-40)(“ASU 2024-03”), which requires disaggregation of certain expense captions into specified categories in disclosures within the footnotes to the financial statements. The objective of this standard is to provide investors with information to better understand a public entity’s performance and prospects for future cash flows, and to compare their performance over time with that of other entities. ASU 2024-03 will be effective for the Company beginning with our 2027 annual financial statements and interim financial statements thereafter, with early adoption permitted. The adoption of ASU 2024-03 will require the Company to provide new footnote disclosure about the types of expenses that are included in certain captions on its Statements of Operations, such as Cost of revenue, Research and development, Sales and marketing, and General and administrative.

In December 2023, the FASB issued ASU 2023-09,Income Taxes (Topic 740): Improvements to Income Tax Disclosures(“ASU 2023-09”), which increases the disclosure requirements around rate reconciliation information and certain types of income taxes companies are required to pay. ASU 2023-09 will be effective for the Company beginning with its 2025 annual financial statements, with early adoption permitted. We expect the adoption of the standard will require certain additional income tax disclosure.

In November 2023, the FASB issued ASU 2023-07,Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”), which improves reportable segment disclosure requirements, including enhancement of the disclosures of significant segment expenses and interim disclosure requirements, to enable investors to better understand an entity’s overall performance and assess potential future cash flows. ASU 2023-07 became effective for the Company beginning with this Annual Report on Form 10-K which includes the required additional segment disclosures.

(3) BUSINESS ACQUISITIONS

On March 3, 2020, Ribbon completed its merger transaction with ECI Telecom Group Ltd (“ECI”) in accordance with the terms of the Agreement and Plan of Merger, dated as of November 14, 2019 (the “ECI Acquisition”). Prior to the ECI Acquisition, ECI was a privately-held global provider of end-to-end packet optical transport and software-defined networking (“SDN”) and network function virtualization solutions for service providers, enterprises and data center operators.

The ECI Acquisition was accounted for as a business combination and the financial results of ECI are included in the Company’s consolidated financial statements. Costs related to the integration of the Company and ECI are included in the Acquisition-, disposal- and integration-related expenses in the table below.

Acquisition-, Disposal- and Integration-Related Expenses

Acquisition-related expenses include those expenses related to acquisitions that would otherwise not have been incurred by the Company, including professional and services fees, such as legal, audit, consulting, paying agent and other fees, and expenses related to cash payments to certain former executives of the acquired businesses in connection with their employment agreements. Disposal-related expenses are professional and services fees related to disposals of subsidiaries or portions of the business. Integration-related expenses represent incremental costs related to combining the Company and its business acquisitions, such as third-party consulting and other third-party services related to merging the previously separate companies’ systems and processes.

The integration-related expenses in the years ended December 31, 2023 and 2022 relate to the ECI Acquisition. The disposal-related expenses in the year ended December 31, 2022 primarily related to costs incurred from the sale ofone of our foreign subsidiaries.

The components of Acquisition-, disposal- and integration-related expenses incurred in the years ended December 31, 2024, 2023 and 2022 were as follows (in thousands):

(4) SALE OF KANDY COMMUNICATIONS BUSINESS

The Company completed the Kandy Sale on December 1, 2020 (the “Kandy Sale Date”). As consideration, AVCT paid Ribbon $45.0 million, subject to certain adjustments, in the form of Debentures and AVCT Warrants (collectively the “AVCT Units”). The Company received 43,778 AVCT Units as sale consideration.

The Debentures bore interest at a rate of 10% per annum, which was added to the principal amount of the Debentures. The Debentures were subject to mandatory conversion if the AVCT stock price was at or above $6.00 per share for 40 trading days in any 60 consecutive trading day period, subject to the satisfaction of certain other conditions. As of February 19, 2021, the stock price had traded above $6.00 for 40 days within a 60 consecutive trading day period, and accordingly, on September 8, 2021 (the “Debenture Conversion Date”), upon the completion of customary regulatory filings by AVCT, the Debentures were converted into 13,700,421 shares of AVCT common stock (the “Debenture Shares”).

The AVCT Warrants were independent of the Debentures and entitled the Company to purchase 4,377,800 shares of AVCT common stock at an exercise price of $0.01 per share.

The Company calculated the fair value of the Debentures at each measurement date using a Lattice-based valuation approach, which utilizes a binomial tree to model the different paths the price of AVCT’s common stock might take over

the Debentures’ life by using assumptions regarding the stock price volatility and risk-free interest rate. The Company used the Black-Scholes valuation model for estimating the fair value of the AVCT Warrants at each measurement date. The fair value of the AVCT Warrants was affected by AVCT’s stock price as well as valuation assumptions, including the volatility of AVCT’s stock price, expected term of the option, risk-free interest rate and expected dividends. Both the Lattice and Black-Scholes valuation models are based on available market data, giving consideration to all of the rights and obligations of each instrument and precluding the use of “blockage” discounts or premiums in determining the fair value of a large block of financial instruments.

On August 29, 2022, the Company and AVCT entered into a settlement agreement which provided for, amongst other things, the cancellation of the Company’s investment in the Debenture Shares and the AVCT Warrants with an aggregate fair value of $2.6 million. Pursuant to the settlement agreement, the Company and AVCT also entered into a Wind Down Agreement, pursuant to which a Reseller Agreement between the parties, as previously amended, was terminated, and the Company was granted a non-exclusive perpetual license to use and modify certain intellectual property owned by AVCT comprising WebRTC gateway technology that is integrated with Ribbon’s SBCs and Application Servers. As consideration, the Company paid AVCT $2.5 million in cash, the Debenture Shares were redeemed and canceled, and the AVCT Warrants were terminated and canceled. The perpetual license granted by AVCT is classified as Intangible assets, net in the Company’s consolidated balance sheet as of December 31, 2024 and 2023 in the amount of $1.0 million and $2.4 million, respectively.

The Company hadno investment in AVCT as of December 31, 2024 or 2023 due to the settlement agreement entered into on August 29, 2022. The Company recorded losses of $41.3 million in the year ended December 31, 2022, representing the change in the fair value of the AVCT Investment.

The results of the Kandy Communications Business are excluded from the Company’s consolidated results for all periods subsequent to the Kandy Sale Date.

(5) EARNINGS (LOSS) PER SHARE

Basic earnings (loss) per share is computed by dividing net income (loss) by the weighted average number of shares outstanding during the period. For periods in which the Company reports net income, diluted net earnings per share is determined by using the weighted average number of common and dilutive common equivalent shares outstanding during the period, unless the effect is antidilutive.

The shares used to compute loss per share were as follows (in thousands):

Options to purchase the Company’s common stock and unvested restricted and performance-based stock units aggregating 7.6 million shares,13.5 million shares, and 14.5 million shares were excluded from the computation of diluted loss per share for the years ended December 31, 2024, 2023 and 2022, respectively, because their effect would have been antidilutive.

As of December 31, 2024 and 2023, the potential number of dilutive shares from the Warrants totaled 4.9 million shares. However, there was no impact on weighted average shares outstanding from these Warrants for the years ended December 31, 2024 and 2023 as the average share price of the Company’s common stock was below the exercise price of $3.77 per share and their effect would have been antidilutive.

Dividends accrued on the Preferred Stock were not an adjustment to net income (loss) used for the calculation of diluted earnings (loss) per share as these dividends are included in the fair value adjustment of the Preferred Stock which was reflected in Other expense, net until the redemption of the Preferred Stock on June 25, 2024.

(6) FAIR VALUE HIERARCHY

Fair value is the price 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 on assumptions that market participants would use in pricing an asset or a liability. The three-tier fair value hierarchy is based on the level of independent, objective evidence surrounding the inputs used to measure fair value. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. The fair value hierarchy is as follows:

The Company did not have any transfers between Level 2 and Level 3 fair value measurements during the years ended December 31, 2024 and 2023.

(7) ACCOUNTS RECEIVABLE, NET

Accounts receivable, net, consisted of the following (in thousands):

The Company’s allowance for doubtful accounts activity was as follows (in thousands):

(8) INVENTORY

Inventory consisted of the following (in thousands):

(9) PROPERTY AND EQUIPMENT

Property and equipment consisted of the following (in thousands):

As of December 31, 2024 and 2023, property and equipment included $23.2 million and $3.4 million, respectively, of assets that had not yet commenced depreciation. These assets primarily consisted of leasehold improvements and equipment, with the most significant portion related to construction in progress at our new main campus in Petah Tikva, Israel that is expected to be completed and occupied in the 1 st half of 2025, totaling $18.9 million and $0.5 million as of December 31, 2024 and 2023, respectively.

The Company recorded depreciation and amortization expense related to property and equipment of $13.5 million for the year ended December 31, 2024, $14.1 million for the year ended December 31, 2023 and $15.3 million for the year ended December 31, 2022. During each of these years, the Company disposed of certain property and equipment that was fully depreciated at the time of disposal, which resulted in reductions in both Cost and Accumulated depreciation.

The net book values of the Company’s property and equipment by geographic area were as follows (in thousands):

(10) INTANGIBLE ASSETS AND GOODWILL

The Company’s intangible assets at December 31, 2024 and 2023 consisted of the following (in thousands):

Estimated future amortization expense for the Company’s intangible assets at December 31, 2024 was as follows (in thousands):

Goodwill is recorded when the consideration for an acquisition exceeds the fair value of net tangible and identifiable intangible assets acquired. For the purpose of testing goodwill for impairment, all goodwill is assigned to a reporting unit, which may be either an operating segment or a portion of an operating segment. The Company’sreporting units are itstwo operating segments, Cloud and Edge and IP Optical Networks. Testing for impairment of goodwill is completed annually as of October 1 st. The Company’s IP Optical Networks operating segment, with $76.0 million of associated goodwill, had a negative carrying value and a positive fair value as of October 1, 2024.

Upon completion of the 2024 and 2023 annual tests for goodwill impairment, the Company determined that there wasno impairment of goodwill in either of its reporting units. There wasno change in the carrying value of the Company’s goodwill in the years ended December 31, 2024 and 2023.

The components of goodwill at December 31, 2024 and 2023 were as follows (in thousands):

(11) ACCRUED EXPENSES AND OTHER

Accrued expenses and other consisted of the following (in thousands):

(12) WARRANTY

The changes in the Company’s warranty accrual balance in the years ended December 31, 2024 and 2023 were as follows (in thousands):

(13) RESTRUCTURING AND FACILITIES CONSOLIDATION INITIATIVES

The Company recorded restructuring and related expense aggregating $10.2 million, $16.2 million and $10.8 million in the years ended December 31, 2024, 2023 and 2022, respectively. Restructuring and related expense includes restructuring expense (primarily severance and related costs), estimated future variable and other lease costs for vacated properties with no intent or ability of sublease, and accelerated rent amortization expense.

For restructuring events that involve lease assets and liabilities, the Company applies lease reassessment and modification guidance and evaluates the right-of-use assets for potential impairment. If the Company plans to exit all or distinct portions of a facility and does not have the ability or intent to sublease, the Company will accelerate the amortization of each of those lease components through the vacate date. The accelerated amortization is recorded as a component of Restructuring and related expense in the Company’s consolidated statements of operations. Related variable lease expenses will continue to be expensed as incurred through the vacate date, at which time the Company will reassess the liability balance to ensure it appropriately reflects the remaining liability associated with the premises and record a liability for the estimated future variable lease costs.

Accelerated amortization of lease assets is recognized from the date that the Company commences the plan to fully or partially vacate a facility, for which there is no intent or ability to enter into a sublease, through the final vacate date. Amounts of accelerated rent amortization that are included as a component of restructuring and related expense are not included in the tables below, as the liability for the total lease payments for each respective facility is included as a component of Operating lease liabilities in the Company’s consolidated balance sheets at December 31, 2024 and 2023, both current and noncurrent (see Note 21). The Company may incur additional future expense if it is unable to sublease other locations included in the Facilities Initiative.

The components of restructuring and related expense for the years ended December 31, 2024, 2023 and 2022 were as follows (in thousands):

The Company’s President and CEO approved workforce reductions in 2024 for certain of the Company’s operating locations to correspond with the current sales levels in those areas. The Company recorded $2.1 million in the year ended December 31, 2024 related to these actions.

2023 Restructuring Plan

On February 22, 2023, the Company’s Board of Directors approved a strategic restructuring program (the “2023 Restructuring Plan”) to streamline the Company’s operations in order to support the Company’s investment in critical growth areas. The 2023 Restructuring Plan includes, among other things, charges related to a workforce reduction. Any potential positions eliminated in countries outside the United States are subject to local law and consultation requirements.

In connection with the 2023 Restructuring Plan, the Company recorded restructuring and related expense of $2.0 million and $9.9 million in the years ended December 31, 2024 and 2023, respectively, consisting entirely for severance related costs. A summary of the 2023 Restructuring Plan accrual activity for the years ended December 31, 2024 and 2023 were as follows (in thousands):

The Company estimates that it will record nominal future expense under the 2023 Restructuring Plan.

2022 Restructuring Plan

On February 14, 2022, the Company’s Board of Directors approved a strategic restructuring program (the “2022 Restructuring Plan”) to streamline the Company’s operations in order to support the Company’s investment in critical growth areas. The 2022 Restructuring Plan includes, among other things, charges related to a consolidation of facilities and a workforce reduction. Any positions eliminated in countries outside the United States are subject to local law and consultation requirements.

The Company recorded restructuring and related expense of $6.1 million and $6.3 million in connection with the 2022 Restructuring Initiative in the years ended December 31, 2024 and 2023, respectively. The amount for the year ended December 31, 2023 was comprised of $5.3 million for variable and other facilities-related costs and $1.0 million for accelerated amortization of lease assets no longer being used with no ability or intent to sublease. The Company estimates that it will record approximately $5 million of expense in 2025 under the 2022 Restructuring Plan. A

summary of the 2022 Restructuring Plan accrual activity for the years ended December 31, 2024 and 2023 were as follows (in thousands):

Balance Sheet Classification

The current portions of accrued restructuring were $1.4 million and $1.1 million at December 31, 2024 and 2023, respectively, and are included as components of Accrued expenses in the consolidated balance sheets. The long-term portions of accrued restructuring are included as components of Other long-term liabilities in the consolidated balance sheets. The long-term portions of accrued restructuring were $0.8 million and $1.1 million at December 31, 2024 and 2023, respectively.

(14) DEBT

2024 Credit Facility

On June 21, 2024, the Company entered into a Senior Secured Credit Facilities Credit Agreement (the “2024 Credit Facility” or “Credit Agreement”) as guarantor, with the Company’s wholly-owned subsidiary, Ribbon Communications Operating Company, Inc., as the borrower (the “Borrower”), HPS Investment Partners, LLC ("HPS"), as administrative agent, and HPS and WhiteHorse Capital Management, LLC ("WhiteHorse" and, together with HPS, the "Lenders"), pursuant to which the Lenders provided the Company with a $385 million Credit Agreement comprised of (i) a $350 million term loan (the “2024 Term Loan”) and (ii) a $35 million revolving credit facility (the “2024 Revolver”), including a $20 million sublimit for letters of credit. The proceeds received from the 2024 Term Loan were used to (a) repay 100% of the amounts outstanding under the 2020 Credit Facility, (b) redeem in full the Preferred Stock and (c) pay fees and expenses related to the 2024 Credit Facility. The excess proceeds are being used by the Company for working capital and other general corporate purposes.

The 2024 Term Loan and the 2024 Revolver bear interest, at the Borrower’s option, at either the Alternate Base Rate (“ABR”) or Term Secured Overnight Financing Rate ("SOFR") with an Applicable Margin for each (all as defined in the 2024 Credit Facility). Margins for the first six months are 5.25% per annum for ABR Loans and 6.25% per annum for SOFR Loans. Thereafter, margins vary based on the Company’s Consolidated Net Leverage Ratio, ranging from 4.75% to 5.25% per annum for ABR Loans and 5.75% to 6.25% per annum for SOFR Loans. The 2024 Term Loan and the 2024 Revolver will both mature on June 21, 2029. The 2024 Term Loan is being repaid in equal quarterly installments: approximately $0.9 million beginning with the third quarter of 2024 through the second quarter of 2025; approximately $2.2 million beginning with the third quarter of 2025 and ending with the second quarter of 2027; and approximately $4.4 million quarterly thereafter, with the remaining principal balance of approximately $298.4 million due on the maturity date of June 21, 2029. In connection with the establishment of the 2024 Credit Facility, $7.7 million of original issue discount was withheld by the Lenders and the Company incurred $6.3 million of debt issuance costs for a total of $14.0 million that is being amortized to Interest expense, net over the term of the 2024 Credit Facility.

The 2024 Credit Facility requires compliance with a Maximum Consolidated Net Leverage Ratio (the "Financial Covenant"), as defined in the 2024 Credit Facility, which is tested on a quarterly basis. The Company was in compliance with the Financial Covenant as of December 31, 2024.

The indebtedness and other obligations under the 2024 Credit Facility are irrevocably and unconditionally guaranteed on a joint and several basis by the Company and its subsidiaries (together, the "Guarantors"). The 2024 Credit Facility is secured on a first-priority basis by liens on substantially all assets of the Borrower and the Guarantors.

2020 Credit Facility

On June 21, 2024, the Company used the proceeds from the 2024 Credit Facility to, among other things, repay all amounts outstanding under its Senior Secured Credit Facilities Credit Agreement, dated March 3, 2020 (as amended, the "2020 Credit Facility"), by and among the Company, as a guarantor, Ribbon Communications Operating Company, Inc., as the borrower (the "Borrower"), Citizens Bank, N.A., Santander Bank, N.A., and others as lenders ("2020 Credit Facility Lenders"). The Company wrote off $2.0 million of debt issuance costs in conjunction with the early extinguishment of the 2020 Credit Facility.

On March 3, 2020, the Company entered into a Senior Secured Credit Facilities Credit Agreement (as amended, the “2020 Credit Facility”), by and among the Company, as a guarantor, Ribbon Communications Operating Company, Inc., as the borrower (“Borrower”), Citizens Bank, N.A. (“Citizens”), Santander Bank, N.A., and others as lenders, (“Lenders”). The proceeds of the Credit Agreement were used, in part, to pay off in full all obligations of the Company under the 2019 Credit Facility.

The 2020 Credit Facility had a maturity date of March 2025 and originally provided for $500 million of commitments from the 2020 Credit Facility Lenders to the Borrower, comprised of $400 million in term loans (the “2020 Term Loan Facility”) and a $100 million facility available for revolving loans (the “2020 Revolving Credit Facility”). Under the 2020 Revolving Credit Facility, a $30 million sublimit was originally available for letters of credit and a $20 million sublimit was available for swingline loans.

The indebtedness and other obligations under the 2020 Credit Facility were unconditionally guaranteed on a senior secured basis by the Company, Edgewater Networks, Inc., a wholly-owned subsidiary of the Company, and GENBAND Inc., wholly-owned subsidiary of the Company (together, the “2020 Credit Facility Guarantors”). The 2020 Credit Facility was secured by first-priority liens on substantially all of the assets of the Borrower and the 2020 Credit Facility Guarantors, including substantially all of the assets of the Company.

The 2020 Credit Facility required compliance with certain financial covenants, including a minimum Consolidated Fixed Charge Coverage Ratio and a maximum Consolidated Net Leverage Ratio (each as defined in the 2020 Credit Facility, and each tested on a quarterly basis).

On March 10, 2022, the Company entered into the Fourth Amendment to the 2020 Credit Facility to increase the Maximum Consolidated Net Leverage Ratio (as defined in the 2020 Credit Facility) and in conjunction, the Company made a $15.0 million prepayment that was applied to the final payment due on the maturity date.

On June 30, 2022, the Company entered into the Fifth Amendment to the 2020 Credit Facility (the “Fifth Amendment”) to increase the Maximum Consolidated Net Leverage Ratio (as defined in the 2020 Credit Facility) for 2022, with the fourth quarter of 2022 increased to 4.75:1.00, the first and second quarters of 2023 declining to 3.25:1.00, and in all subsequent quarters the ratio was to be fixed at 3.00:1.00. Also, the Fifth Amendment reduced the minimum Consolidated Fixed Charge Coverage Ratio (as defined in the 2020 Credit Facility) in 2022, with the fourth quarter of 2022 reduced to 1.10:1.00 and in all subsequent quarters the ratio was to be fixed at 1.25:1.00. In addition, the Fifth Amendment increased the maximum rate at which loans were to bear interest if the Company’s Consolidated Net Leverage Ratio for any quarter was greater than 4.50:1.00. Specifically, loans incurred were to bear interest, at the Borrower’s option, at either LIBOR plus a margin ranging from 1.50% to 4.50% per year, or the base rate plus 0.50%, or the prime rate plus a margin ranging from 0.50% to 3.50% per year. The Fifth Amendment also allowed the Company to incur junior secured or unsecured debt in an amount no less than $50 million, subject to certain conditions, including the requirement that 50% of the aggregate amount of such incurred debt (net of certain costs, fees and other amounts) must be applied to prepay the 2020 Credit Facility, and compliance with certain leverage ratio-based covenant exceptions. In connection with the Fifth Amendment, the Company made a $10.0 million voluntary prepayment that was applied to the final payment due on the maturity date. Subsequent to the Fifth Amendment, the Company was required to make

quarterly principal payments on the 2020 Term Loan aggregating approximately $5.0 million per quarter through March 31, 2024 and $10.0 million in each of the three quarters thereafter, with the remaining and final payment due on the maturity date in March 2025.

On March 24, 2023, the Company entered into the Sixth Amendment to the 2020 Credit Facility (the “Sixth Amendment”) effective March 30, 2023. The Sixth Amendment, among other things, increased the Maximum Consolidated Net Leverage Ratio (as defined in the 2020 Credit Facility), for the first, second and third quarters of 2023 to 4.50:1.00. In the fourth quarter of 2023 and the first quarter of 2024, the Maximum Consolidated Net Leverage Ratio declined to 4.25:1.00 and 4.00:1.00, respectively. Also, the Sixth Amendment reduced the minimum Consolidated Fixed Charge Coverage Ratio (as defined in the 2020 Credit Facility) to 1.10:1.00 through the first quarter of 2024. The Sixth Amendment reduced the maximum borrowings allowed under the 2020 Revolving Credit Facility from $100 million to $75 million and the sublimit available for letters of credit was reduced from $30 million to $20 million. In addition, the Sixth Amendment replaced LIBOR with SOFR as the alternative rate available to the Company for calculating interest owed under the 2020 Credit Facility with the margin fixed at 4.5%. In conjunction with the Sixth Amendment, the Company made a $75 million prepayment that was applied to the final payment due upon maturity in March 2025. The $75 million prepayment was almost entirely funded with the net proceeds from the Private Placement and the sales of the Company’s interest rate swap. Debt issuance costs associated with the Sixth Amendment totaled $1.7 million and were being amortized on a straight-line basis over the remaining life of the 2020 Credit Facility and were written off in conjunction with the early extinguishment of the 2020 Credit Facility on June 21, 2024.

The Company’s interest rates under the 2020 Term Loan benefited from a hedge instrument that was in place, specifically a fixed rate swap, until it was sold in March 2023 (see Note 15). Following the sale of the fixed rate swap in March 2023, the Company’s interest rate was based upon U.S. dollar SOFR plus a fixed margin of 4.5%. The Company

was in compliance with all covenants of the 2020 Credit Facility at December 31, 2023, including the Consolidated Net Leverage Ratio calculation that considered the Company’s debt to include Preferred Stock.

The Company had the following outstanding borrowings, unamortized debt issuance costs and original issue discount, letters of credit, interest rates, and remaining borrowing capacity under the 2024 Credit Facility and the 2020 Credit Facility as of December 31, 2024 and 2023, respectively:

The Company’s debt maturities as of December 31, 2024 were as follows:

Letters of Credit and Other Guarantees

The Company uses letters of credit, bank guarantees, and surety bonds in the course of its business. At December 31, 2024, the Company had $10.9 million of letters of credit, bank guarantees, and surety bonds outstanding (collectively, "Guarantees") under various uncommitted facilities andno letters of credit outstanding under the 2024 Credit Facility. At December 31, 2023, the Company had Guarantees aggregating $7.9 million, comprised of the $2.7 million of letters of credit under the 2020 Credit Facility described above and $5.2 million of Other Guarantees. At December 31, 2024 and 2023, the Company had cash collateral of $2.7 million and $0.1 million, respectively, supporting the Guarantees, which are reported in Restricted cash in the Company’s consolidated balance sheets.

(15) DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES

The Company is exposed to financial market risk related to foreign currency fluctuations and changes in interest rates. These exposures are actively monitored by management. To manage the volatility related to the exposure to changes in interest rates, the Company may enter into derivative financial instruments. Management’s objective has been to reduce, where it is deemed appropriate to do so, fluctuations in earnings and cash flows associated with changes in interest rates. Ribbon’s policies and practices are to use derivative financial instruments only to the extent necessary to manage exposures. Ribbon does not hold or issue derivative financial instruments for trading or speculative purposes.

The Company records derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a specific risk, such as interest rate risk, are considered fair value hedges. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Derivatives may also be designated as hedges of the foreign currency exposure of a net investment in a foreign operation. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge, or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk even though hedge accounting does not apply or the Company elects not to apply hedge accounting.

Cash Flow Hedge of Interest Rate Risk

As of December 31, 2023, the 2020 Term Loan Facility had an outstanding balance of $235.4 million and the Revolving Credit Facility was undrawn. Borrowings under the 2020 Credit Facility had variable interest rates based on SOFR (see Note 14). As a result of exposure to interest rate movements, during March 2020, the Company entered into an interest rate swap arrangement, which effectively converted its $400 million term loan with its variable interest rate based upon one-month LIBOR to an aggregate fixed rate of 0.904%, plus a leverage-based margin as defined in the 2020 Credit Facility.

On July 22, 2022, the Company sold $30 million of the notional amount of its interest rate swap back to its counterparty for $1.5 million, reducing the notional amount of this swap to $370 million. On August 16, 2022, the Company sold another $30 million of the notional amount of its interest rate swap back to its counterparty for $1.6 million, reducing the notional amount to $340 million, which approximated the current level of our term loan debt then outstanding. The gain in accumulated other comprehensive (loss) income related to the $60 million notional amount sold of $3.1 million was being released into earnings on a straight line basis over the remaining term of the 2020 Credit Facility as a decrease to interest expense until it was refinanced on June 21, 2024, the amortization of which totaled $0.4 million and $0.9 million for the years ended December 31, 2024 and 2023, respectively. The remaining unamortized gain in accumulated other comprehensive (loss) income of approximately $0.5 million was written off to interest expense in conjunction with the refinancing of the 2020 Credit Facility on June 21, 2024. See Note 14 for a description of the refinancing.

On March 24, 2023, the Company received $9.4 million, consisting of $0.4 million of interest and $9.0 million for the sale of $170 million of its $340 million notional amount interest rate swap back to its counterparty, reducing the notional amount to $170 million. On March 27, 2023, the Company received $9.8 million, consisting of $0.4 million of interest and $9.4 million for the sale of the remaining $170 million of its interest rate swap back to its counterparty. The portion of the gain in accumulated other comprehensive (loss) income related to the term loan debt prepaid on the date of the final sale of our swap totaled $7.3 million and was released into earnings immediately as Other expense, net. The portion of the gain in accumulated other comprehensive (loss) income related to our remaining term loan debt balance was $12.0 million and was being released into earnings on a straight line basis over the remaining term of the 2020 Credit Facility as a decrease to interest expense until it was refinanced on June 21, 2024, the amortization of which totaled $3.0 million and $4.7 million for the years ended December 31, 2024 and 2023, respectively. The remaining

unamortized gain in accumulated other comprehensive (loss) income of $4.4 million was written off to interest expense in conjunction with the refinancing of the 2020 Credit Facility on June 21, 2024. See Note 14 for a description of the refinancing.

The Company’s objectives in using interest rate derivatives have been to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish this objective, the Company has used an interest rate swap as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount.

The effective portion of changes in the fair value of designated derivatives that qualify as cash flow hedges is recorded in Accumulated other comprehensive income in the consolidated balance sheet and is subsequently reclassified into earnings in the period that the hedged forecasted transactions affect earnings. During the year ended December 31, 2023, such a derivative was used to hedge the variable cash flows associated with the outstanding borrowings under the 2020 Credit Facility and the Company accounted for this derivative as an effective hedge until the final portion of the swap was sold on March 27, 2023. Any ineffective portion of the change in the fair value of the derivative would have been recognized directly in earnings. However, there was no hedge ineffectiveness recorded over the life of the swap.

Amounts reported in Accumulated other comprehensive income related to the Company’s derivative were reclassified to interest expense as interest was accrued on the Company’s variable-rate debt. The impact of the Company’s derivative financial instrument on its consolidated statements of comprehensive loss for the years ended December 31, 2024 and 2023 was as follows, net of tax (in thousands):

The Company hadno derivative assets or liabilities at December 31, 2024 or 2023.

(16) PREFERRED STOCK AND WARRANTS

On March 28, 2023, the Company issued 55,000 shares of Preferred Stock to investors in the Private Placement at a price of $970 per share, along with 4,858,090 Warrants with an exercise price of $3.77 per share.

On June 25, 2024, the Company redeemed the Preferred Stock with a portion of the proceeds from the refinancing of the 2020 Credit Facility at a rate of 103% for a total of approximately $63.5 million. The Warrants remain outstanding and without modification. See Note 14 for a description of the refinancing of the 2020 Credit Facility.

The Company accounted for the Preferred Stock until it was redeemed and continues to account for the Warrants as liability-classified instruments based on an assessment of their specific terms in accordance with ASC Topic 480,Distinguishing Liabilities from Equity. The fair value option was elected for the Preferred Stock, as the Company considered fair value to best reflect its expected future economic value. These liabilities are remeasured to fair value at each reporting date using the same valuation methodology applied upon issuance using current input assumptions.

The value of the Preferred Stock was calculated quarterly through March 31, 2024 using the Black-Derman-Toy (BDT) stochastic yield lattice model to capture the optimal timing of repayment, increasing dividend rate and other features and the value of the Warrants is calculated using the Black-Scholes Pricing Model.

Changes in the fair value of the Preferred Stock and Warrants are reported as Other expense, net in the Company’s consolidated statements of operations.

The Company determined the fair value of the Warrants using Level 3 input. The key assumptions input into the models utilized were as follows as of December 31, 2024 and 2023:

The changes in the Company’s Preferred Stock for the year ended December 31, 2024 and 2023 were as follows (in thousands):

The changes in the Company’s Warrant liabilities for the years ended December 31, 2024 and 2023 were as follows (in thousands):

The Preferred Stock, redeemed on June 25, 2024, was subordinate to the Company’s indebtedness and senior to the Company’s common stock or other equity. Holders of the Preferred Stock were entitled to cumulative dividends that accrued quarterly. Dividends were payable in-kind during the first year at a rate of 9.25%. At the Company’s option, the dividends were payable in-kind or in cash during the second year at a rate of 9.75%. Dividends thereafter were to be payable in cash at a rate of 12.00%. The proceeds from the Preferred Stock issuance were approximately $53.4 million, including $10.0 million from existing related party stockholders. Offering costs paid by the Company of approximately $3.5 million were recorded in Other expense, net in the year ended December 31, 2023. The net proceeds from the Private Placement were used for the repayment of debt. The Preferred Stock was redeemable on or after the first and second anniversaries of the closing date at a rate of 103% and 102%, respectively.

The Warrants are immediately exercisable and upon an event such as a merger, consolidation, asset sale or similar change of control, the Warrants may be exercised and the holders may vote the underlying shares of common stock. In connection with the Private Placement, the Company provided the investors with certain registration rights relating to the Preferred Stock, the Warrants and the shares of the Company’s common stock underlying the Warrants, that required the Company to file a registration statement on Form S-3 with the SEC within 30 days following the closing date of the Private Placement. The registration requirement was completed on May 19, 2023.

(17) REVENUE RECOGNITION

The Company’s typical performance obligations include the following:

Significant Judgments

The Company’s contracts with customers often include promises to transfer multiple products and services to the customer. Determining whether products and services are considered distinct performance obligations that should be accounted for separately versus together may require significant judgment.

Judgment is required to determine the SSP for each distinct performance obligation. The Company typically has more than one SSP for individual products and services due to the stratification of those products and services by customers and circumstances. In these instances, the Company may use information such as the size of the customer and geographic region in determining the SSP.

Deferred Revenue

Deferred revenue is a contract liability representing amounts collected from or invoiced to customers in excess of revenue recognized. This results primarily from the billing of annual customer support agreements where the revenue is recognized over the term of the agreement. The value of deferred revenue will increase or decrease based on the timing of invoices and recognition of revenue.

Disaggregation of Revenue

The Company disaggregates its revenue from contracts with customers based on the nature of the products and services and the geographic regions in which each customer is domiciled. The Company’s total revenue for the years ended December 31, 2024, 2023 and 2022 was disaggregated geographically as follows:

The Company’s product revenue from its direct sales program and from indirect sales through its channel partner program for the years ended December 31, 2024,2023 and 2022 was as follows (in thousands):

The Company’s product revenue from sales to enterprise customers and from sales to service provider customers for the years ended December 31, 2024,2023 and 2022 was as follows (in thousands):

The Company’s product revenue and service revenue components by segment for the years ended December 31, 2024,2023 and 2022 was as follows (in thousands):

Revenue Contract Balances

The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables, which are contract assets, and customer advances and deposits, which are contract liabilities, in the Company’s consolidated balance sheets. Amounts are billed as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals or upon achievement of contractual milestones. Billing may occur subsequent to revenue recognition, resulting in contract assets. The Company may receive advances or deposits from its customers before revenue is recognized, resulting in contract liabilities which are classified as deferred revenue. These assets and liabilities are reported in the Company’s consolidated balance sheets on a contract-by-contract basis as of the end of each reporting period. Changes in the contract asset and liability balances during the years ended December 31, 2024 and 2023 were not materially impacted by any factors other than billing and revenue recognition. Nearly all of the Company’s deferred revenue balance is related to services revenue, primarily customer support contracts. Unbilled receivables stem primarily from engagements where services have been performed; however, billing cannot occur until services are completed.

In some arrangements, the Company allows customers to pay for term-based software licenses and products over the term of the software license. The Company also sells SaaS-based software under subscription arrangements, with payment terms over the term of the SaaS agreement. Amounts recognized as revenue in excess of amounts billed are recorded as unbilled receivables. Unbilled receivables that are anticipated to be invoiced in the next twelve months are included in Accounts receivable on the Company’s consolidated balance sheets. The changes in the Company’s accounts receivable, unbilled receivables and deferred revenue balances for the years ended December 31, 2024 and 2023 were as follows (in thousands):

The Company recognized approximately $110 million of revenue in the year ended December 31, 2024 that was recorded as deferred revenue at December 31, 2023 and approximately $108 million of revenue in the year ended December 31, 2023 that was recorded as deferred revenue at December 31, 2022. Of the Company’s deferred revenue reported as long-term in its consolidated balance sheet at December 31, 2024, the Company expects that approximately $10 million will be recognized as revenue in 2026, approximately $5 million will be recognized as revenue in 2027 and approximately $6 million will be recognized as revenue in 2028 and beyond.

The Company applies the optional exemption of not disclosing the transaction price allocated to the remaining performance obligation for its contracts with an original duration of less than one year. In 2024, the Company entered into a contract with an existing customer that has revenue allocated to remaining performance obligations, which includes unearned revenue and amounts that will be invoiced and recognized as revenue in future periods of $285 million as of December 31, 2024. The Company expects to recognize the remaining revenue over the next three years.

All freight-related customer invoicing is recorded as revenue, while the shipping and handling costs that occur after control of the promised goods or services transfer to the customer are reported as fulfillment costs, a component of Cost of revenue - product in the Company’s consolidated statements of operations.

Deferred Commissions Cost

Sales commissions earned by the Company’s employees are considered incremental and recoverable costs of obtaining a contract with a customer. The payments related to these costs have been deferred on our consolidated balance sheet and are being amortized over the expected life of the customer contract, which is generally five years. At December 31, 2024 and 2023, the Company had $2.8 million and $3.0 million, respectively, of deferred sales commissions capitalized.

(18) OPERATING SEGMENT INFORMATION

The Company hastwo operating and reportable segments, Cloud and Edge and IP Optical Networks, that align with the way the business is managed. The Company’s CODM, its President and Chief Executive Officer, makes key operating decisions and assesses performance based upon these reportable segments.

The Cloud and Edge segment provides secure and reliable software and hardware products, solutions and services for enabling Voice over Internet Protocol ("VoIP") communications, Voice over Long-Term Evolution ("VoLTE") and Voice Over 5G ("VoNR") communications, and Unified Communications and Collaboration ("UC&C") within service provider and enterprise networks and from the cloud. The Cloud and Edge products are increasingly software-centric and cloud-native for deployment on private, public or hybrid cloud infrastructures, in data centers, on enterprise premises and within service provider networks. Ribbon's Cloud and Edge product portfolio consists primarily of its Session Border Controller ("SBC") products and its Network Transformation products.

The IP Optical Networks segment provides high-performance, secure solutions for IP networking and optical

transport, supporting wireless networks including 5G, metro and edge aggregation, core networking, data center interconnect, legacy transformation and transport solutions for wholesale carriers. This portfolio is offered to service provider, enterprise and industry verticals with critical transport network infrastructures including utilities, government, defense, transportation, and education and research.

The Company does not provide segment asset information as such information is not provided to the CODM and accordingly, asset information is not used in assessing segment performance. Segment revenue and expenses included in the tables below represent direct revenue and expense attributable to each segment. Please see Note 10 for information regarding the allocation of goodwill between segments.

The CODM utilizes adjusted gross profit to evaluate each segment's performance. The Company calculates adjusted gross profit by excluding from cost of revenue both amortization of acquired technology and stock-based compensation and may also exclude other items in future periods that the Company believes are not part of the Company's core business. The Company uses adjusted gross profit to develop its annual budget and quarterly forecasts. The CODM analyzes adjusted gross profit compared to the annual budget and quarterly forecasts to allocate resources.* *Ribbon’s calculation of adjusted gross profit may not be comparable to similarly titled measures used by other companies. See below for a reconciliation of segment adjusted gross profit to gross profit and loss before income taxes.

The tables below present significant segment expenses regularly reviewed by the CODM for the years ended December 31, 2024, 2023 and 2022 (in thousands):

(19) MAJOR CUSTOMERS

The following customers contributed 10% or more of the Company’s revenue in at least one of the years ended December 31, 2024, 2023 and 2022:

At December 31, 2024 and 2023, no customer accounted for 10% or more of the Company’s accounts receivable balance. The Company performs ongoing credit evaluations of its customers and generally does not require collateral on accounts receivable. The Company maintains an allowance for doubtful accounts and such losses have historically been within management’s expectations.

(20) STOCK-BASED COMPENSATION PLANS

The Company grants stock-based compensation to employees, officers and non-employee directors, as well as consultants and advisors of the Company and its subsidiaries under its Amended and Restated 2019 Incentive Award Plan which provides for the award of stock options, stock appreciation rights, restricted stock awards (“RSAs”), performance-based stock awards, restricted stock units (“RSUs”), performance-based stock units (“PSUs”) and other stock- or cash-based awards.

Executive Equity Arrangements

Inducement Awards

In connection with his appointment as President and Chief Executive Officer of Ribbon on March 16, 2020, the Company awarded Bruce McClelland sign-on equity grants, comprised of RSUs and a PSU grant with both market and service conditions. The market conditions surrounding the PSUs granted were not met by the expiration date of September 1, 2024 and therefore, the associated shares have been cancelled.

Performance-Based Stock Grants

In addition to granting RSAs and RSUs to its executives and certain of its employees, the Company also grants PSUs to certain of its executives and certain other employees. Vesting periods for RSAs, RSUs, and PSUs granted range fromone tothree years. PSUs granted consist of 60% that have both performance and service conditions (the “Performance PSUs”) and 40% that have both market and service conditions (the “Market PSUs”). Each Performance PSU is comprised ofthree consecutive fiscal year performance periods beginning in the year of grant, with one-third of the Performance PSUs attributable to each fiscal year performance period. The Market PSUs haveone three-year performance period, beginning January 1 in the year of grant and ending on December 31, three years thereafter. The number of shares of common stock underlying the PSUs that can be earned will not exceed 200% of the Performance or Market PSUs. Shares subject to PSUs that fail to be earned will be forfeited.

Restricted Stock Units

The activity related to the Company’s RSUs for the year ended December 31, 2024 was as follows:

The total grant date fair value of restricted stock underlying RSUs that vested was $15.5 million in the year ended December 31, 2024, $19.3 million in the year ended December 31, 2023 and $18.1 million in the year ended December 31, 2022.

Performance-Based Stock Units

The activity related to the Company’s PSUs for the year ended December 31, 2024 was as follows:

The total grant date fair value of restricted stock underlying PSUs that vested was $0.9 million in the year ended December 31, 2024, $2.6 million in the year ended December 31, 2023 and $0.9 million in the year ended December 31, 2022.

Stock-Based Compensation

The consolidated statements of operations included stock-based compensation for the years ended December 31, 2024, 2023 and 2022 as follows (in thousands):

At December 31, 2024, there was $14.1 million, net of expected forfeitures, of unrecognized stock-based compensation expense related to unvested RSUs and PSUs. This expense is expected to be recognized over a weighted average period of approximately 1.2 years. The Company issues authorized and unissued shares under its equity plans and at December 31, 2024, there were approximately 2.0 million total shares of common stock reserved for that purpose with 0.1 million of those shares authorized only for issuance of shares upon exercise of stock options.

(21) LEASES

The Company has operating leases for corporate offices and research and development facilities and has historically had finance leases for certain equipment. Operating leases are reported separately in the Company’s consolidated balance sheets. Assets acquired under finance leases, if any, are included in Property and equipment, net, in the consolidated balance sheets.

The Company determines if an arrangement is a lease at inception. A contract is determined to contain a lease component if the arrangement provides the Company with a right to control the use of an identified asset. Lease agreements may include lease and non-lease components. In such instances for all classes of underlying assets, the Company does not separate lease and non-lease components but rather, accounts for the entire arrangement under leasing guidance. Leases with an initial term of 12 months or less are not recorded on the balance sheet and lease expense for these leases is recognized on a straight-line basis over the lease term.

Right-of-use assets and lease liabilities are initially measured based on the present value of the future minimum fixed lease payments (i.e., fixed payments in the lease contract) over the lease term at the commencement date. As the Company’s existing leases do not have a readily determinable implicit rate, the Company uses its incremental borrowing rate based on the information available at the commencement date in determining the present value of future minimum fixed lease payments. The Company calculates its incremental borrowing rate to reflect the interest rate that it would have to pay to borrow on a collateralized basis an amount equal to the lease payments in a similar economic environment over a similar term and considers its historical borrowing activities and market data from entities with comparable credit ratings in this determination. The measurement of the right-of-use asset also includes any lease payments made prior to the commencement date (excluding any lease incentives) and initial direct costs incurred. The Company assessed its right-of-use assets for impairment as of December 31, 2024 and 2023 and determinedno impairment has occurred.

Lease terms may include options to extend or terminate the lease and the Company incorporates such options in the lease term when it has the unilateral right to make such an election and it is reasonably certain that the Company will exercise that option. In making this determination, the Company considers its prior renewal and termination history and planned usage of the assets under lease, incorporating expected market conditions.

For operating leases, lease expense for minimum fixed lease payments is recognized on a straight-line basis over the lease term. The expense for finance leases includes both interest and amortization expense components, with the interest component calculated based on the effective interest method and the amortization component calculated based on straight-line amortization of the right-of-use asset over the lease term. Lease contracts may contain variable lease costs, such as common area maintenance, utilities and tax reimbursements that vary over the term of the contract. Variable lease costs are not included in minimum fixed lease payments and as a result, are excluded from the measurement of the right-of-use assets and lease liabilities. The Company expenses all variable lease costs as incurred.

Certain leased facilities are being partially or fully vacated as part of the 2022 Restructuring Plan and for some of those facilities, the Company has no plans to enter into sublease agreements. Accordingly, the Company accelerated the amortization of those lease assets through the planned cease-use date of each facility, resulting in additional amortization expense of $1.0 million and $1.6 million in the years ended December 31, 2023 and 2022, respectively. No additional amortization was recorded in the year ended December 31, 2024. No variable lease costs were accrued in the years ended December 31, 2024 or 2023 for future estimated variable expenses related to assets partially or fully vacated with no intent or ability to sublease. Variable lease costs for the year ended December 31, 2022 included accruals of $1.0 million for all estimated future variable lease costs related to those facilities.

All incremental accelerated amortization and accrual for all estimated future variable lease costs are included in Restructuring and related expense in the Company’s consolidated statements of operations for the years ended December 31, 2024, 2023 and 2022. At December 31, 2024 and 2023, the Company had accruals of $1.1 million and $1.5 million, respectively, for all future anticipated variable lease costs related to these facilities. The Company may incur additional future expense if it is unable to sublease other locations included in the Facilities Initiative.

The Company leases its corporate offices and other facilities under operating leases, which expire at various times through 2033.

The Company’s right-of-use lease assets and lease liabilities at December 31, 2024 and 2023 were as follows (in thousands):

The components of lease expense for the years ended December 31, 2024, 2023 and 2022 were as follows (in thousands):

Cash flow information related to the Company’s leases for the years ended December 31, 2024, 2023 and 2022 was as follows (in thousands):

Other information related to the Company’s leases as of December 31, 2024 and 2023 was as follows (in thousands):

Future minimum fixed lease payments under noncancelable leases at December 31, 2024 were as follows (in thousands):

(22) EMPLOYEE DEFINED CONTRIBUTION PLANS

The Company offers 401(k) savings plans to eligible employees. The Company matches 50% of each employee’s contributions to the 401(k) program up to 4% of the employee’s eligible earnings, for a maximum match of 2% of eligible earnings.

The Company recorded expense related to its employee defined contribution plans aggregating $3.0 million, $3.0 million and $3.3 million in the years ended December 31, 2024, 2023 and 2022, respectively.

(23) NON-U.S. EMPLOYEE DEFINED BENEFIT PLANS

The Company has defined benefit retirement plans that cover certain employees at various international locations. The Company’s policy is to contribute amounts at least sufficient to satisfy the minimum amount required by applicable law and regulations or to directly pay benefits where appropriate. Benefits under the defined benefit plans are typically based either on years of service and the employee’s compensation (generally during a fixed number of years immediately before retirement) or on annual credits. The range of assumptions that are used for these non-U.S. defined benefit plans reflect the different economic environments within the various countries.

A reconciliation of the changes in the benefit obligations and fair value of the assets of the defined benefit plans for the years ended December 31, 2024 and 2023, the funded status of the plans, and the amounts recognized in the consolidated balance sheets as of December 31, 2024 and 2023 were as follows (in thousands):

The increase in the underfunded status of the Company’s defined benefit plans at December 31, 2024 compared to December 31, 2023 was primarily due to normal benefit accruals combined with significant lump sum payments in Israel of $0.9 million.

Plans with underfunded or non-funded accumulated benefit obligations at December 31, 2024 and 2023 were as follows (in thousands):

Plans with overfunded accumulated benefit obligations at December 31, 2024 and 2023 were as follows (in thousands):

Net periodic benefit costs for the years ended December 31, 2024, 2023 and 2022 were as follows (in thousands):

Expected benefit payments for the next ten years are as follows (in thousands):

The changes in plan assets and benefit obligations recognized in other comprehensive income (loss) before tax for the years ended December 31, 2024, 2023 and 2022 were as follows (in thousands):

The Company defers all actuarial gains and losses resulting from variances between actual results and economic estimates or actuarial assumptions. The unrecognized actuarial gains and losses are recorded as unrealized pension actuarial gains (losses) in the Company’s consolidated balance sheets as a component of Accumulated other comprehensive income. These unrecognized gains and losses are amortized as a component of net periodic benefit cost when the net gains and losses exceed 10% of the greater of the market value of plan assets or the projected benefit obligation at the beginning of the year.

The principal weighted average assumptions used to determine the benefit obligation at December 31, 2024 and 2023 were as follows:

The principal weighted average assumptions used to determine net period benefit cost for the years ended December 31, 2024, 2023 and 2022 were as follows:

Assumed discount rates are used in the measurement of the projected and accumulated benefit obligations, as well as the service and interest cost components of net periodic pension cost. Estimated discount rates reflect the rates at which the pension benefits could be effectively settled. For each defined benefit plan, the Company chooses an estimated discount rate from a readily available market index rate, based upon high-quality fixed income investments, specific to the country or economic zone in which the benefits are paid and taking into account the duration of the plan and the number of participants.

The Company’s plans in both the Netherlands and Switzerland are funded through insurance contracts, which have historically provided guaranteed interest credit. The fair value of these contracts is derived from the insurance companies’ assessment of the minimum value of the benefits provided by the insurance contracts. Due to the plan amendment in 2020 that changed the benefit structure of the Netherlands plan, the Company no longer has any obligation related to this plan beyond the payment of insurance premiums. Therefore, there is no projected benefit obligation andno plan assets in the Netherlands. The methodology used to value the Switzerland plan assets assumes that the value of the plan assets equals the guaranteed insured benefits. For consistency, the same discount rate used in the valuation of the benefit obligations is used to place a value on the plan assets. The assets are assumed to grow each year in line with the discount rate, and therefore, the expected return on the assets is set equal to the discount rate. The fair value of the plan assets in Switzerland was $2.8 million at December 31, 2024 and $2.6 million at December 31, 2023. The Company classifies the fair value of its plan assets as Level 2 in the fair value hierarchy as discussed in Note 6.

During the years ended December 31, 2024 and 2023, employees in Switzerland made contributions aggregating $29,000 and $39,000 each year, respectively. Employee contributions to this plan are based on a fixed 5% of the relevant pensionable earnings. The Company funds this plan by contributing at least the minimum amount required by applicable regulations and as recommended by an independent actuary.

During the years ended December 31, 2024, 2023 and 2022, the Company contributed $0.7 million, $1.0 million and $2.0 million, respectively, in total to its defined benefit plans. The Company expects to contribute $1.5 million in total to its defined benefit plans in 2025.

(24) INCOME TAXES

The components of loss from continuing operations before income taxes consisted of the following (in thousands):

The provision (benefit) for income taxes from continuing operations consisted of the following (in thousands):

A reconciliation of the Company’s effective tax rate for continuing operations to the U.S. statutory federal rate is as follows:

The following is a summary of the significant components of deferred income tax assets and liabilities (in thousands):

The deferred tax assets and liabilities based on tax jurisdictions are presented in the Company’s consolidated balance sheets as follows:

At December 31, 2024, the Company had U.S. federal net operating losses (“NOLs”) of $100.2 million. The Company also had U.S. state NOLs of $51.0 million. In addition, the Company had $1.6 billion of Israel NOLs. The U.S. federal NOL carryforwards expire between 2025 and 2037. The U.S. state NOLs begin to expire in 2025, and the Company also has indefinite-lived state NOLs. The Israel NOLs do not expire.

The Company also has available federal, state and foreign income tax credit carryforwards of $25.4 million. The federal foreign tax credit carryforwards expire between 2030 and 2032. The state tax credits, which are primarily research and development credits, begin to expire in 2025, while others can be carried forward until exhausted. The foreign income tax credits expire in various periods.

The Company has provided for income taxes on the undistributed earnings of its non-U.S. subsidiaries as of December 31, 2024, excluding Ireland and Israel. These subsidiaries, excluding Ireland and Israel, are cost-plus or limited risk distributors that are not anticipated to need to use excess funds locally. Accordingly, the Company is required to recognize and record deferred taxes in 2024. The deferred taxes, which are primarily future withholding taxes, are recorded on the entire outside basis differences related to the foreign subsidiaries, the largest of these differences being undistributed earnings. Undistributed profits of Ireland and Israel, as well as other outside basis differences in foreign subsidiaries, were indefinitely reinvested in foreign operations. Quantification of the deferred tax liability, if any, associated with indefinitely reinvested earnings and outside basis differences was not practicable.

Under the provisions of the Internal Revenue Code, the net operating losses and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service. Net operating losses and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership of significant shareholders over athree-year period in excess of 50%, as defined under sections 382 and 383 of the Internal Revenue Code, as well as similar state provisions. As a result of the Sonus and GENBAND merger in 2017, the Company has $92.8 million of U.S. federal net operating loss carryforwards remaining as of December 31, 2024 with an annual section 382 limitation of $9.7 million. The Company believes these NOLs are fully realizable. As a result of the ECI Acquisition in 2020, the Company has $9.6 million of U.S. federal NOLs remaining as of December 31, 2024 with an annual section 382 limitation of $1.1 million. The Company does not believe all of these NOLs are realizable and, therefore, have recorded a partial valuation allowance against these NOLs.

The Company performed an analysis to determine if, based on all available evidence, it considered it more likely than not that some portion or all of the recorded deferred tax assets will not be realized in a future period. Accordingly, the Company has recorded a valuation allowance against its U.S. deferred tax assets of $18.6 million at December 31, 2024 and $23.4 million at December 31, 2023. The Company also maintains a valuation allowance against certain of its foreign deferred tax assets, predominantly Israel, amounting to approximately $475 million at December 31, 2024 and $465 million at December 31, 2023. The deferred tax assets recognized with no valuation allowance at December 31, 2024 and 2023 primarily relate to other foreign subsidiaries where recoverability is concluded to be more likely than not based on the Company’s cost-plus compensation policy, as well as NOLs and tax credits in the U.S. that are expected to be utilized prior to expiration.

A reconciliation of the Company’s unrecognized tax benefits is as follows (in thousands):

The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for income taxes. The Company had $6.7 million, $14.0 million and $14.9 million of unrecognized tax benefits, including penalties and interest, at December 31, 2024, 2023 and 2022, respectively. Of these amounts, $3.6 million, $10.5 million and $11.2 million represent the amount of unrecognized tax benefits that, if recognized, would impact the effective income tax rate for the years ended December 31, 2024, 2023 and 2022, respectively. The Company recorded income tax expense (benefit) for potential penalties and interest of $(2.2) million, $0.2 million and $(0.3) million for the years ended December 31, 2024, 2023 and 2022, respectively. The Company had $0.9 million and $3.2 million accrued in Other long-term liabilities for penalties and interest at December 31, 2024 and 2023, respectively. The Company believes that it is reasonably possible that $0.4 million in tax positions related to its unrecognized tax benefits will be recognized within the next twelve months.

The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction as well as various state and foreign jurisdictions. Generally, the tax years 2021 through 2024 remain open to examination by the major taxing jurisdictions in which the Company operates. The Company’s federal and state NOLs generated prior to 2020 could be adjusted on examination even though the year in which the loss was generated is otherwise closed by the statute of limitations.

As of December 31, 2024, the Company had ongoing income tax audits in certain foreign countries. Management believes that an adequate provision has been recorded for any adjustments that may result from tax examinations.

(25) RELATED PARTIES

The Company recognized revenue from its largest stockholder of $11.3 million, $12.8 million and $6.6 million in the years ended December 31, 2024, 2023 and 2022, respectively. The Company’s accounts receivable from its largest shareholder totaled $5.5 million and $3.9 million as of December 31, 2024 and 2023, respectively. Additionally, as discussed in Note 16, certain related party stockholders participated in the Private Placement.

(26) COMMITMENTS AND CONTINGENCIES

Contingencies

Liabilities for Royalty Payments to the IIA

Prior to the ECI Acquisition, ECI had received research and development grants from the IIA. The Company assumed ECI’s contract with the IIA, which requires the Company to pay royalties to the IIA on proceeds from the sale of products which the Israeli government has supported by way of research and development grants. The royalties for grants prior to 2017 were calculated at the rates of 1.3% to 5.0% of the aggregated proceeds from the sale of such products developed at certain of the Company’s R&D centers, up to an amount not exceeding 100% of such grants plus interest at LIBOR. Effective for grants approved in 2017 and effective through 2023, interest was calculated at the higher of LIBOR plus 1.5% to 2.75%. For grants approved in 2024 and thereafter, interest is calculated based on SOFR. At December 31, 2024, the Company had $1.5 million of unpaid royalties accrued. The Company’s maximum possible future royalties commitment at December 31, 2024 of $14.0 million, including interest of $0.8 million, was based upon estimates of future sales of products and services and the grants received from the IIA not yet repaid.

Litigation

The Company is often a party to disputes and legal proceedings that it considers routine and incidental to its business, including those described below. The Company believes that it has meritorious defenses to the allegations made in the pending cases and intends to vigorously defend these lawsuits; however, the Company is currently unable to forecast the ultimate outcome of these or similar matters. Since it is difficult to predict the outcome of legal proceedings, it is possible that the ultimate outcomes could materially and adversely affect the Company’s business, financial position, results of operations or cash flows. Accordingly, with respect to these proceedings, the Company is currently unable to reasonably estimate the possible loss or range of possible loss.

Miller Complaint. On November 8, 2018, Ron Miller, a purported stockholder of the Company, filed a Class Action Complaint (the “Miller Complaint”) in the United States District Court for the District of Massachusetts (the “Massachusetts District Court”) against the Company andthree of its former officers (collectively, the “Defendants”), claiming to represent a class of purchasers of Sonus common stock during the period from January 8, 2015 through March 24, 2015 and alleging violations of the federal securities laws. Similar to a previous complaint entitled Sousa et al. vs. Sonus Networks, Inc. et al., which was dismissed with prejudice by an order dated June 6, 2017, the Miller Complaint claims that the Defendants made misleading forward-looking statements concerning Sonus’ expected fiscal first quarter of 2015 financial performance, which statements were also the subject of an August 7, 2018 Securities and Exchange Commission Cease and Desist Order, whose findings the Company neither admitted nor denied. The Miller plaintiffs were seeking monetary damages.

After the Miller Complaint was filed, several parties filed and briefed motions seeking to be selected by the Massachusetts District Court to serve as a Lead Plaintiff in the action. On June 21, 2019, the Massachusetts District Court appointed a group as Lead Plaintiffs and the Lead Plaintiffs filed an amended complaint on July 19, 2019. On August 30, 2019, the Defendants filed a motion to dismiss the Miller Complaint and, on October 4, 2019, the Lead Plaintiffs filed an opposition to the motion to dismiss. In June 2023, the Defendants agreed to a settlement in principle with the named plaintiffs, and final approval of the settlement was provided by the court on April 24, 2024. The settlement provided a release of all claims asserted in the litigation to all Defendants, who continue to deny liability. The

$4.5 million settlement amount was funded by the provider of the Company’s Directors and Officers liability insurance policy.

Charter Complaint. On September 19, 2022, Charter Communications Operating, LLC (“Charter”) filedtwo complaints againsttwo of our subsidiaries (Sonus Networks, Inc. and Ribbon Communications Operating Company, Inc.) alleging breach of contract with respect to indemnification obligations purportedly owed to Charter in connection with Charter’s legal dispute with Sprint Communications Company L.P., which was settled by Charter in March 2022. One complaint was filed in the Supreme Court of the State of New York, in New York County; the second complaint was filed by Charter as well as co-plaintiffs Charter Communications Holding Company, LLC and Bright House Networks, LLC, in the Superior Court of the State of Delaware in and for New Castle County. In both complaints, Charter is seeking monetary damages. The Company filed its answer to the first complaint file in New York on December 7, 2022 and to the second complaint filed in Delaware on January 9, 2023. Discovery is on-going and the court in the Delaware complaint has set a trial date of June 2025. No trial date has been set for the case in New York.

WideOpenWest Complaint. On August 9, 2023, WideOpenWest, Inc. and WideOpenWest Finance, LLC (collectively, “WOW”) filed a complaint against Ribbon alleging breach of contract with respect to indemnification obligations purportedly owed to WOW in connection with WOW’s legal dispute with Sprint Communications Company L.P., which was settled by WOW in the second quarter of 2023. The complaint was filed in the 429th Judicial District of the District Court of the State of Texas, in Collin County, Texas and has since been transferred to the 493rd Judicial District Court in Collin County. In the complaint, WOW is seeking monetary damages. The Company filed its answer to the complaint on October 5, 2023. On October 14, 2024, the Company and WOW agreed to settle this matter. In connection with the settlement, the Company will pay WOW a total of $5.0 million, with $2.0 million paid at the time of settlement and the remaining $3.0 million paid over the next 18-months in equal quarterly installments.