Ecovyst Inc.

1. Background and Basis of Presentation:

Description of Business

Ecovyst Inc. and subsidiaries (the “Company” or “Ecovyst”) is a leading provider of regenerated sulfuric acid, virgin sulfuric acid, and sulfur dioxide and related derivatives, which the Company believes are essential to its customers’ operations and processes. The Company supports customers through its strategically located network of manufacturing facilities. The Company believes that its products and services contribute to improving the sustainability of the environment.

The Company has a uniquely positioned specialty business which provides regenerated sulfuric acid to the North American refining industry for the production of alkylate and provides high quality and high strength virgin sulfuric acid for industrial and mining applications. Ecovyst also provides chemical waste handling and treatment services, as well as ex-situ catalyst activation services for the refining and petrochemical industry. As a result of the June 30, 2026 acquisition of the Calabrian sulfur dioxide and sulfur derivatives business, the Company further expanded its product offering into sulfur dioxide, sodium bisulfite, sodium thiosulfate and sodium metabisulfite products for mining, water treatment, energy and other specialty applications, including food and pharmaceuticals (see Note 8 for more information on this transaction).

The Company’s regenerated sulfuric acid product typically experiences seasonal fluctuations as a result of higher demand for gasoline products in the summer months and lower demand in the winter months. These demand fluctuations result in higher sales and working capital requirements in the second and third quarters.

Basis of Presentation

The condensed consolidated financial statements included herein are unaudited. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) have been condensed or omitted pursuant to such rules and regulations for interim reporting. In the opinion of management, all adjustments of a normal and recurring nature necessary to state fairly the financial position and results of operations have been included. The results of operations are not necessarily indicative of the expected results for the full year. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025.

On December 31, 2025, the Company completed the sale of its Advanced Materials & Catalysts business, which includes the Company’s investment in affiliated companies, Zeolyst International and Zeolyst C.V. (collectively, the “Zeolyst Joint Venture”). The financial results of this business are presented as discontinued operations in the condensed consolidated financial statements. See Note 3 for more information on this transaction.

The notes to the condensed consolidated financial statements, unless otherwise indicated, are on a continuing operations basis.

2. New Accounting Standards:

Accounting Standards Recently Adopted

In July 2025, the Financial Accounting Standards Board (“FASB”) issued guidance related to the estimation of expected credit losses for current accounts receivable and current contract assets that arise from transactions accounted for under ASC 606. This new guidance introduces a practical expedient for entities that assumes that current conditions as of the balance sheet date do not change for the remaining life of the asset. The new guidance is effective for fiscal years beginning after December 15, 2025 and interim periods within those fiscal years, with early adoption permitted. The Company has elected the practical expedient and applied the guidance as of January 1, 2026, with no material impact on the condensed consolidated financial statements and related disclosures.

Accounting Standards Not Yet Adopted

In November 2024, the FASB issued guidance requiring public business entities (“PBEs”) to disclose additional information on the nature of certain expenses presented in the income statement. The new guidance requires tabular disclosure of significant expense categories and qualitative descriptions for amounts not disaggregated from relevant expense categories. PBEs are required to define selling expenses and disaggregate the components. The new guidance is effective for fiscal years beginning after December 15, 2026 and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. The requirements must be applied prospectively; however, PBEs have the option to apply the guidance retrospectively. The disclosure will be implemented as required for the fiscal year ended December 31, 2027. The Company is currently evaluating the impact of this guidance.

In September 2025, the FASB issued guidance which is intended to modernize the accounting for the costs of internal-use software. The amendments remove all references to prescriptive and sequential development stages and, instead, require an entity to start capitalizing software costs when management has authorized and committed to funding the software project, and it is probable that the project will be completed and the software will be used to perform the function intended. The new guidance is effective for fiscal years beginning after December 15, 2027 and interim periods within, with early adoption permitted. PBEs have the option to apply the guidance prospectively or retrospectively. The Company is currently evaluating the impact of this guidance.

In May 2026, the FASB issued guidance which establishes accounting requirements for environmental credit assets and environmental credit obligations. The new guidance introduces a comprehensive model that establishes recognition, measurement, presentation, and disclosure requirements for environmental credits and, when applicable, compliance obligations that may be settled by using environmental credits. The new guidance is effective for fiscal years beginning after December 15, 2027 and interim periods within, with early adoption permitted. The requirements must be applied retrospectively. The disclosure will be implemented as required for the fiscal year beginning January 1, 2028. The Company is currently evaluating the impact of this guidance.

3. Divestiture:

Advanced Materials & Catalysts Divestiture

On September 10, 2025, the Company entered into a definitive agreement to sell its Advanced Materials & Catalysts business, which includes the Zeolyst Joint Venture, to Technip Energies N.V. (the “Buyer”) for a purchase price of $556,000 subject to certain adjustments including indebtedness, cash, working capital and transaction expenses, as set forth in the definitive agreement (the “Advanced Materials & Catalysts Sale”).

The Company completed the Advanced Materials & Catalysts Sale effective on December 31, 2025. During the year ended December 31, 2025, the net cash proceeds to the Company from the sale were $568,427 after certain customary adjustments for indebtedness, working capital and cash at the closing of the transaction.

In accordance with the Company’s agreement with the Buyer regarding the determination of the final purchase price, a $3,750 post-closing purchase price adjustment was recorded during the quarter ended June 30, 2026, which reflects an adjusted purchase price of $559,596. During the three months ended September 30, 2026, the Company made a payment to the buyer for $11,247, representing the net working capital adjustment to the sale price. The Company classified the payment within net cash used in investing activities in the condensed consolidated statements of cash flows.

The following table summarizes the results of discontinued operations related to the Advanced Materials & Catalysts business for the three and nine months ended September 30, 2025:

(1)Upon the close of the Advanced Materials & Catalysts Sale and finalization of net cash proceeds, the Company was required to provide partial repayment under its Term Loan Credit Agreement dated as of January 30, 2025 (the “2025 Term Loan Facility”). As such, interest expense has been allocated to discontinued operations on the basis of the Company’s partial repayment of $161,500 of the 2025 Term Loan Facility due June 12, 2031.

During the three months ended September 30, 2026, the Company incurred a net loss from discontinued operations, net of tax of $199, primarily driven by transaction costs of $278.

During the nine months ended September 30, 2026, the Company incurred a net loss from discontinued operations, net of tax of $4,462, primarily driven by transaction costs of $1,365 and the $3,750 post-closing purchase price adjustment.

Upon the close of the transaction, the Company entered into a transition services agreement with the Buyer pursuant to which the buyer is receiving certain services to provide for the orderly transition of various functions and processes after the closing of the transaction. The services under the transition services agreement include information technology, accounting, tax, financial services, human resources and other administrative support services. These services are being provided at cost for a period of 10 months, with the ability to extend the initial term up totwo extensions, the first of which shall not exceed two months and the second shall not exceed one month. The Company invoiced $448 and $1,962 pursuant to the transition services agreement to the Buyer during the three and nine months ended September 30, 2026, respectively.

The disposal group included the Company’s investment in an affiliated company, which was historically accounted for under the equity method. The following table provides summarized financial information of the combined investments in affiliated companies that were included within the divested business unit:

Certain administrative services are provided to the affiliated company by the Company. The Company charged $576 and $1,728 for the three and nine months ended September 30, 2025, respectively, which were included in selling, general and administrative expenses in the condensed consolidated statements of income (loss).

4. Revenue from Contracts with Customers:

Disaggregated Revenue

The Company’s primary means of disaggregating revenue is by key products and services, which are described in the table below.

The following table disaggregates the Company’s sales by key products and services, for the three and nine months ended September 30, 2026 and 2025, respectively:

(1)As described in Note 1 to these condensed consolidated financial statements, the Company experiences seasonal fluctuations in sales of its regenerated sulfuric acid product.

5. Fair Value Measurements:

Fair values are based on quoted market prices when available. When market prices are not available, fair values are generally estimated using discounted cash flow analyses, incorporating current market inputs for similar financial instruments with comparable terms and credit quality. In instances where there is little or no market activity for the same or similar instruments, the Company estimates fair values using methods, models and assumptions that management believes a hypothetical market participant would use to determine a current transaction price. These valuation techniques involve some level of management estimation and judgment that becomes significant with increasingly complex instruments or pricing models. Where appropriate, adjustments are included to reflect the risk inherent in a particular methodology, model or input used.

The Company’s financial assets and liabilities carried at fair value have been classified based upon a fair value hierarchy. The hierarchy gives the highest ranking to fair values determined using unadjusted quoted prices in active markets for identical assets and liabilities (Level 1) and the lowest ranking to fair values determined using methodologies and models with unobservable inputs (Level 3). The classification of an asset or a liability is based on the lowest level input that is significant to its measurement. For example, a Level 3 fair value measurement may include inputs that are both observable (Levels 1 and 2) and unobservable (Level 3). The levels of the fair value hierarchy are as follows:

•Level 1—Values are unadjusted quoted prices for identical assets and liabilities in active markets accessible at the measurement date. Active markets provide pricing data for trades occurring at least weekly and include exchanges and dealer markets.

•Level 2—Inputs include quoted prices for similar assets or liabilities in active markets, quoted prices from those willing to trade in markets that are not active, or other inputs that are observable or can be corroborated by market data for the term of the instrument. Such inputs include market interest rates and volatilities, spreads and yield curves.

•Level 3—Certain inputs are unobservable (supported by little or no market activity) and significant to the fair value measurement. Unobservable inputs reflect the Company’s best estimate of what hypothetical market participants would use to determine a transaction price for the asset or liability at the reporting date.

Fair value on a recurring basis

The following tables present information about the Company’s assets and liabilities that were measured at fair value on a recurring basis as of September 30, 2026 and December 31, 2025, and indicates the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value.

Derivative contracts

Derivative assets and liabilities can be exchange-traded or traded over-the-counter (“OTC”). The Company generally values exchange-traded derivatives using models that calibrate to market transactions and eliminate timing differences between the closing price of the exchange-traded derivatives and their underlying instruments. OTC derivatives are valued using market transactions and other market evidence whenever possible, including market-based inputs to models, model calibration to market transactions, broker or dealer quotations or alternative pricing sources with reasonable levels of price transparency. When models are used, the selection of a particular model to value an OTC derivative depends on the contractual terms of, and specific risks inherent in, the instrument as well as the availability of pricing information in the market. The Company generally uses similar models to value similar instruments. Valuation models require a variety of inputs, including contractual terms, market prices and rates, forward curves, measures of volatility, and correlations of such inputs. For OTC derivatives that trade in liquid markets, such as forward contracts, swaps and options, model inputs can generally be corroborated by observable market data by correlation or other means, and model selection does not involve significant management judgment.

As of September 30, 2026, the Company had interest rate caps that were fair valued using Level 2 inputs. In addition, the Company applies a credit valuation adjustment to reflect credit risk which is calculated based on credit default swaps. To the extent that the Company’s net exposure under a specific master agreement is an asset, the Company utilizes the counterparty’s default swap rate. If the net exposure under a specific master agreement is a liability, the Company utilizes a default swap rate comparable to Ecovyst. The credit valuation adjustment is added to the discounted fair value to reflect the exit price that a market participant would be willing to receive to assume the Company’s liabilities or that a market participant would be willing to pay for the Company’s assets.

6. Stockholders' Equity:

Accumulated Other Comprehensive Income (Loss)

The following tables present the tax effects of each component of other comprehensive income (loss) for the three and nine months ended September 30, 2026 and 2025, respectively:

The following tables present the changes in accumulated other comprehensive income (loss) (“AOCI”), net of tax, by component for the nine months ended September 30, 2026 and 2025, respectively:

(1)See the following table for details about these reclassifications. Amounts in parentheses indicate debits.

The following table presents the reclassifications out of AOCI for the three and nine months ended September 30, 2026 and 2025, respectively:

(1)Amounts in parentheses indicate debits to profit/loss.

(2)These AOCI components are components of net periodic pension and other postretirement cost (see Note 14 to these condensed consolidated financial statements for additional details).

Treasury Stock Repurchases

2022 Stock Repurchase Program

On April 27, 2022, the Company’s board of directors (the “Board”) approved a stock repurchase program that authorized the Company to purchase up to $450,000 of the Company’s common stock over thefour-year period from the date of approval (the “Stock Repurchase Program”). On October 30, 2025, the Board amended the Stock Repurchase Program to remove the limitation that all repurchases must be made within thefour-year period from the date of original approval. Under the plan, the Company is permitted to repurchase shares from time to time for cash in open market transactions or in privately negotiated transactions in accordance with applicable federal securities laws, with the Company determining the timing and the amount of any repurchases based on its evaluation of market conditions, share price andother factors.

During the nine months ended September 30, 2026, the Company repurchased 3,490,180 shares on the open market at an average price of $11.01 per share, for a total of $38,424, excluding brokerage commissions and accrued excise tax. During the nine months ended September 30, 2026, the Company accrued $293 of excise tax related to these repurchases, net of shares issued under the Company’s equity incentive program (see Note 17 to these condensed consolidated financial statements). As of September 30, 2026, $143,783 was available for share repurchases under the program.

During the nine months ended September 30, 2025, the Company repurchased 3,536,364 shares on the open market at an average price of $7.74 per share, for a total of $27,387, excluding brokerage commissions and accrued excise tax. During the nine months ended September 30, 2025, the Company accrued $193 of excise tax related to these repurchases, net of shares issued under the Company’s equity incentive program (see Note 17 to these condensed consolidated financial statements).

Tax Withholdings on Equity Award Vesting

In connection with the vesting of restricted stock awards (“RSA” or “RSAs”), restricted stock units (“RSU” or “RSUs”) and performance stock units (“PSU” or “PSUs”), shares of common stock may be delivered to the Company by employees to satisfy withholding tax obligations at the instruction of the employee award holders. These transactions, when they occur, are accounted for as stock repurchases by the Company, with the shares returned to treasury stock at a cost representing the payment by the Company of the tax obligations on behalf of the employees in lieu of shares for the vesting event. There were 121,608 and 189,446 shares delivered to the Company to cover tax payments for the nine months ended September 30, 2026 and 2025, respectively, and the fair value of those shares withheld were $1,253 and $1,477 for the nine months ended September 30, 2026 and 2025, respectively.

7. Goodwill:

The change in the carrying amount of goodwill for the nine months ended September 30, 2026 is summarized as follows:

The Company completes its annual goodwill and indefinite-lived intangible assets impairment test during the fourth quarter of each year, or more frequently if triggering events indicate a possible impairment. The Company determined the fair value of its reporting unit using both a market approach and an income, or discounted cash flow, approach. As of October 1, 2025, the date of the Company’s most recent quantitative assessments, the fair value of the Company’s reporting unit and the fair value of the Company’s indefinite-lived trade names and trademarks exceeded their respective carrying values.

During the nine months ended September 30, 2026, the Company did not identify any events or circumstances that would more likely than not reduce the fair value of the Company’s reporting unit below its carrying value.

8. Acquisitions:

Calabrian

On June 30, 2026 (the “Closing Date”), the Company completed its acquisition of the Calabrian sulfur dioxide and sulfur derivatives business ("Calabrian") from INEOS Calabrian Holdings Limited and INEOS Calabrian Canada Holdings Limited (the “Sellers”) for a purchase price of $190,000 subject to certain adjustments including indebtedness, cash, and working capital, pursuant to the share purchase agreement (the “Calabrian Acquisition”). The Company paid $183,286 in cash after certain customary adjustments for indebtedness, working capital and $4,753 of cash acquired at the closing of the transaction. As of September 30, 2026, the Company recorded a $986 adjustment to increase the estimated purchase price.

The Calabrian Acquisition will broaden the Company's existing product offering through further expansion into the sulfur dioxide, sodium bisulfite, sodium thiosulfate and sodium metabisulfite product groups for mining, water treatment, energy and other specialty applications, including food and pharmaceuticals.

The Calabrian Acquisition is a business combination, therefore the acquisition method was applied. Under the acquisition method, the purchase price was allocated to the identifiable net assets acquired based on the fair values of the identifiable net assets acquired as of the Closing Date. The excess of the purchase price over fair values of the identifiable net assets acquired was recorded to goodwill.

The table below presents the provisional fair values allocated to the net assets acquired. The purchase accounting and purchase price allocation for Calabrian are preliminary and the Company continues to refine the preliminary valuation of certain acquired net assets which could impact the amount of residual goodwill recorded. The Company intends to finalize the amounts recognized as it obtains the information necessary to complete the analysis, but no later than one year from the date of the acquisition. Final determination of the fair values may result in further adjustments to the values presented in the following table:

The purchase price allocation was updated during the third quarter of 2026 for certain adjustments based on revised estimates of fair value as shown above. Adjustments to the preliminary amounts during the measurement period that result in changes to depreciation, amortization or other income effects will be recognized in the reporting period(s) in which the adjustments are determined.

In accordance with the requirements of the purchase method of accounting for acquisitions, accounts receivable, inventories and other working capital balances were recorded at fair market value. As of the Closing Date, the fair value of accounts receivable and other working capital balances approximated historical cost. Fair value of inventory is defined as estimated selling prices less the sum of (a) costs of disposal and (b) a reasonable profit allowance for the selling effort of the acquiring entity. The gross contractual amount of accounts receivable at the Closing Date was $13,997, of which there wasno amount deemed uncollectible.

Property, plant and equipment is mostly comprised of land, buildings, machinery and equipment (including furniture and fixtures) and construction in process. The preliminary estimated fair value of property, plant and equipment was primarily determined using a cost approach. The key assumptions of the cost approach include replacement cost (new), physical deterioration, economic useful life, remaining useful life, age and effective age.

The fair value measurements of the identified intangible assets were based primarily on significant unobservable inputs and thus represent a Level 3 measurement as defined in ASC 820 - Fair Value Measurement. Definite-lived intangible assets consist primarily of developed technology and customer relationships. The acquired trade names are expected to have an indefinite useful life. The preliminary developed technology and trade names intangible assets’ fair values were determined utilizing the relief-from-royalty method. The preliminary customer relationships intangible assets' fair value was determined using the excess earnings method. Key assumptions used in estimating future cash flows included projected short-term revenue growth rates, EBITDA margins, discount rates, royalty rates, customer attrition rates, contributory asset charges and obsolescence rates among others.

The goodwill recognized in the Calabrian Acquisition is primarily attributable to the acquisition of an assembled workforce and the significant synergies expected to arise from the integration of the operations of Calabrian into the Company’s operations. The goodwill was assigned to the Company’s single operating segment and is not deductible for tax purposes.

The valuation of intangibles assets acquired and the related weighted-average amortization period are as follows:

The unaudited pro forma financial information is presented in the table below for the three and nine months ended September 30, 2026 and 2025, respectively, as if the Calabrian Acquisition had occurred on January 1, 2025:

The unaudited pro forma combined financial information presented above includes the accounting effects of the acquisition of Calabrian, including, to the extent applicable, the following items: amortization charges from acquired intangible assets; depreciation associated with the step-up in fair value of fixed assets; interest expense associated with incremental borrowings under the Company’s Term Loan Credit Agreement to partially finance the acquisition (see Note 11); adjustments to align Calabrian accounting policies to the Company’s; and the related tax effects. The unaudited pro forma financial information also includes acquisition costs specifically related to the Calabrian Acquisition. The unaudited pro forma information is presented for informational purposes only and is not necessarily indicative of the results of operations that actually would have occurred under the Company’s ownership and management.

Net sales attributable to Calabrian for the three and nine months ended September 30, 2026 were $29,132. Net income attributable to Calabrian wasnot material to the results of the Company for the three and nine months ended September 30, 2026. Acquisition and integration costs were $1,917 and $11,188 for the three and nine months ended September 30, 2026, respectively, and are included in other operating expense, net in the Company’s condensed consolidated statements of income (loss).

Upon the close of the transaction, the Company entered into a transition services agreement with affiliates of the Sellers pursuant to which the Company is receiving certain services to provide for the orderly transition of various functions and processes after the closing of the transaction. The services under the transition services agreement include information technology, tax and other administrative support services. These services are being provided at cost for a period up to 9 months, with the ability to extend the initial term. Charges incurred by the Company pursuant to the transition services agreement during the three and nine months ended September 30, 2026 were not material.

Cornerstone

On May 6, 2025 (the “Cornerstone Acquisition Closing Date”), the Company completed its acquisition of the sulfuric acid production assets of Cornerstone Chemical Company LLC (“Cornerstone”) located in Waggaman, Louisiana. As part of an asset purchase agreement (the “Cornerstone Acquisition”), the Company paid $41,480 in cash, consisting of the $35,000 purchase price plus $6,480 of adjustments for working capital, pursuant to the agreement. The sulfuric acid production assets will be used to increase capacity of virgin sulfuric acid and regenerated sulfuric acid to current and future customers.

The following table sets forth the calculation and final allocation of the purchase price to the identifiable assets acquired with respect to the Cornerstone Acquisition:

In accordance with the requirements of the purchase method of accounting for acquisitions, accounts receivable and inventories were recorded at fair market value. As of the Cornerstone Acquisition Closing Date, the fair value of accounts receivable approximated historical cost. The gross contractual amount of accounts receivable at the Cornerstone Acquisition Closing Date was $9,991, of which there wasno amount deemed uncollectible. Fair value of inventory is defined as estimated selling prices less the sum of (a) costs of disposal and (b) a reasonable profit allowance for the selling effort of the acquiring entity.

Prior to the acquisition, the Company had a preexisting relationship with Cornerstone. The Company had a net payable for a sulfuric acid exchange balance that was settled in the amount of $450. As part of the acquisition terms, the payable was settled at cost, which was recorded separate from the business combination.

The valuation of intangibles assets acquired and the related weighted-average amortization period are as follows:

There wereno acquisition and integration costs for the three months ended September 30, 2026. Acquisition and integration costs for the nine months ended September 30, 2026 were $576, and are included in other operating expense, net in the Company’s condensed consolidated statements of income (loss). Acquisition and integration costs for the three and nine months ended September 30, 2025 were $1,315 and $4,070, respectively, and are included in other operating expense, net in the Company’s condensed consolidated statements of income (loss).

The Company entered into an agreement with Cornerstone to lease the land where the acquired assets are located for a 7-year term plus renewal options. Additionally, Cornerstone will charge the Company for site services and utilities for the location.

9. Other Operating Expense, Net:

A summary of other operating expense, net is as follows:

10. Inventories, Net:

Inventories, net are stated at the lower of cost or net realizable value. Cost is determined using the first-in, first-out (“FIFO”) or average cost method. The components of inventories, net consist of the following:

11. Long-term Debt:

The summary of long-term debt is as follows:

Term Loan Facility

In January 2025, the Company amended its Term Loan Credit Agreement dated as of June 12, 2024 to, among other things, (a) reduce the interest rate applicable to all outstanding SOFR term loans to Term SOFR plus 2.00% per annum from a maximum of Term SOFR plus 2.25% per annum and (b) reduce the interest rate applicable to all outstanding base rate term loans to the alternate base rate plus 1.00% per annum from a maximum of the alternate base rate plus 1.25% per annum.

The Company evaluated the terms of the amendment in accordance with ASC 470-50 Debt - Modification and Extinguishment and determined that the amendment was a modification of debt. As a result, the Company recorded $960 of third-party financing costs within debt modification and extinguishment costs in the condensed consolidated statements of income (loss) for the nine months ended September 30, 2025. No original issue discount was paid in relation to the amendment.

In June 2026, the Company amended its 2025 Term Loan Facility to, among other things, (a) incur an additional $100,000 first lien incremental term loan as a fungible increase to the existing initial term loans and (b) make certain other changes to the existing Term Loan Credit Agreement, as amended. The incremental term loan bears interest at the same variable rate as the initial term loans, which is, at the option of the borrowers, either Term SOFR plus 2.00% per annum or ABR plus 1.00% per annum, and has an identical amortization schedule, maturity date, and collateral (the amended term loans, the “2026 Term Loan Facility”). The net proceeds of the incremental term loan were used to finance the acquisition of Calabrian (see Note 8 for more information on this transaction).

The Company evaluated the terms of the amendment in accordance with ASC 470-50 Debt - Modification and Extinguishment and determined that the amendment was a modification of debt. As a result, the Company recorded $978 of third-party financing costs within debt modification and extinguishment costs in the condensed consolidated statements of income (loss) for the nine months ended September 30, 2026. No original issue discount was paid in relation to the amendment.

The interest rate on the 2026 Term Loan Facility was 5.82% as of September 30, 2026.

ABL Facility

The borrowings under the senior secured asset-based lending revolving credit facility as amended April 10, 2025 (“ABL Facility”) bear interest at a rate equal to an adjusted Term SOFR or the base rate plus a margin of between 1.25% to 1.75% or 0.25% to 0.75%, respectively. The interest rate on the ABL Facility was 7.25% as of September 30, 2026.

Fair Value of Debt

The fair value of a financial instrument is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants. As of September 30, 2026 and December 31, 2025, the fair value of the Company’s term loan facility was $497,088 and $396,591, respectively. The fair value is classified as Level 2 based upon the fair value hierarchy (see Note 5 to these condensed consolidated financial statements for further information on fair value measurements).

12. Financial Instruments:

The Company uses interest rate related derivative instruments to manage its exposure to changes in interest rates on its variable-rate debt instruments. The Company does not speculate using derivative instruments.

By using derivative financial instruments to hedge exposures to changes in interest rates, the Company exposes itself to credit risk and market risk. Credit risk is the failure of the counterparty to perform under the terms of the derivative contract. When the fair value of a derivative contract is an asset, the counterparty owes the Company, which creates credit risk for the Company. When the fair value of a derivative contract is a liability, the Company owes the counterparty and therefore, the Company is not exposed to the counterparty’s credit risk in those circumstances. The Company minimizes counterparty credit risk in derivative instruments by entering into transactions with high quality counterparties. The derivative instruments entered into by the Company do not contain credit-risk-related contingent features.

Market risk is the adverse effect on the value of a derivative instrument that results from a change in interest rates. The market risk associated with the Company’s derivative instruments is managed by establishing and monitoring parameters that limit the types and degree of market risk that may be undertaken.

Use of Derivative Financial Instruments to Manage Interest Rate Risk

The Company is exposed to fluctuations in interest rates on its senior secured credit facilities. Changes in interest rates will not affect the market value of such debt but will affect the Company’s interest payments over the term of the loans. Likewise, an increase in interest rates could have a material impact on the Company’s condensed consolidated statements of cash flows. The Company hedges the interest rate fluctuations on debt obligations through interest rate cap agreements. The Company records these agreements at fair value as assets or liabilities in the condensed consolidated balance sheets. As the derivatives are designated and qualify as cash flow hedges, the gains or losses on the interest rate cap agreements are recorded in stockholders’ equity as a component of other comprehensive income (loss), net of tax. Reclassifications of the gains and losses on the interest rate cap agreements into earnings are recorded as part of interest expense in the condensed consolidated statements of income (loss) as the Company makes its interest payments on the hedged portion of its senior secured credit facilities. Fair value is determined based on estimated amounts that would be received or paid to terminate the contracts at the reporting date based on quoted market prices.

The following table provides a summary of the Company’s interest rate cap agreements:

The current notional amounts of thetwo interest rate cap agreements in effect at September 30, 2026 are $450,000 and $200,000. The Company entered into a $450,000 interest rate cap agreement to mitigate interest rate volatility from November 2025 to October 2026 and a $200,000 interest rate cap agreement to mitigate interest rate volatility from August 2026 to July 2028.

The Company had a $175,000 interest rate cap agreement to mitigate interest rate volatility from August 2024 to July 2026.

In October 2026, the Company entered into an interest rate cap agreement to mitigate interest rate volatility with a cap rate of 3.00% and a notional amount of $150,000 from October 2026 to January 2028, $200,000 from July 2028 to January 2029, and $100,000 from January 2029 to January 2030.

The fair values of derivative instruments held as of September 30, 2026 and December 31, 2025, respectively, are shown below:

The following tables show the effect of the Company’s derivative instruments designated as cash flow hedges on AOCI and the condensed consolidated statements of income (loss) for the three and nine months ended September 30, 2026 and 2025, respectively:

The following table shows the total amounts in the line items presented in the condensed consolidated statements of income (loss) in which the effects of derivatives designated as cash flow hedges are recorded for the three and nine months ended September 30, 2026 and 2025, respectively:

The amount of net unrealized gains in AOCI related to the Company’s cash flow hedges that is expected to be reclassified to the condensed consolidated statements of income (loss) over the next twelve months is $2,297 as of September 30, 2026.

13. Income Taxes:

In September 2026, the Company purchased approximately $23,000 of transferable federal Clean Fuel Production tax credits generated during the 2025 tax year under Section 45Z of the Internal Revenue Code of 1986, as amended (“Clean Fuel Production Tax Credits”) for a cash purchase price of approximately $21,200. The resulting discount of approximately $1,800 is recognized as a reduction of income tax expense as the related credits are utilized.

The effective income tax rate for the three months ended September 30, 2026 was 19.9%, compared to 99.1% for the three months ended September 30, 2025. The effective income tax rate for the nine months ended September 30, 2026 was 26.2%, compared to 117.2% for the nine months ended September 30, 2025. The Company’s effective income tax rates for the three and nine months ended September 30, 2026 and 2025, respectively, fluctuated primarily due to the revaluation of deferred tax assets and liabilities and the change in valuation allowance as a result of the Advanced Materials & Catalysts divestiture in the prior year.

The tax expense for the three and nine months ended September 30, 2025 includes a $15,620 discrete tax expense connected to intraperiod allocation associated with the revaluation of deferred tax assets and liabilities, a valuation allowance against the Company’s Kansas Investment Tax Credits, and an increase in valuation allowance against a portion of the Company’s state net operating losses. In accordance with intraperiod allocation rules, this discrete tax expense is reflected in the tax provision for continuing operations.

The difference between the U.S. federal statutory income tax rate and the Company’s effective income tax rate for the nine months ended September 30, 2026 was primarily attributable to state and local taxes, a stock compensation tax shortfall, non-deductible transaction costs associated with the Calabrian Acquisition, a benefit from the remeasurement of state deferred tax assets and liabilities resulting from changes in the Company's expected state apportionment profile following the Calabrian Acquisition, and the partial recognition of the purchase discount on the Clean Fuel Production Tax Credits.

The difference between the U.S. federal statutory income tax rate and the Company’s effective income tax rate for the nine months ended September 30, 2025 was mainly due to state and local taxes, a shortfall tax expense related to stock compensation, tax benefit related to state tax refunds associated with prior tax years, discrete tax expense related to intraperiod allocation associated with the revaluation of deferred tax assets and liabilities, a valuation allowance against the Company’s Kansas Investment Tax Credits, and a valuation allowance against a portion of the Company’s state net operating losses.

14. Benefit Plans:

The following table presents the components of net periodic (benefit) expense for the Company-sponsored defined benefit pension plan, which cover certain employees and retirees located in the U.S.:

Defined Benefit Pension Plans

Net periodic (benefit) expense for the Company-sponsored postretirement benefit plan was not material for the three and nine months ended September 30, 2026 and 2025. All components ofnet periodic (benefit) expenseare presented within other expense (income), net in the Company’s condensed consolidated statements of income (loss).

In conjunction with the Calabrian Acquisition, the Company acquired the Calabrian Corporation Retirement Plan (the "Calabrian Plan"). The Calabrian Plan is administered by Principal Financial Group and was frozen on August 27, 2010. The Company assumed $1,542 of pension assets and $1,435 of pension liabilities, a net asset of $107, which is included in other long-term assets in the Company’s condensed consolidated balance sheets.

15. Commitments and Contingent Liabilities:

There is a risk of environmental impact in the Company’s manufacturing operations. The Company’s environmental policies and practices are designed to comply with existing laws and regulations and to minimize the possibility of significant environmental impact. The Company is also subject to various other lawsuits and claims with respect to matters such as governmental regulations, labor and other actions arising out of the normal course of business. All claims that are probable and reasonably estimable have been accrued for in the Company’s condensed consolidated financial statements. When these matters are ultimately concluded and determined, the Company believes that there will be no material adverse effect on its condensed consolidated financial position, results of operations or liquidity.

16. Segment Information:

The segment information herein excludes the results of the divested Advanced Materials & Catalysts segment, which is reflected in discontinued operations as described in Note 3, for all periods presented.

The Company hasone operating segment which representsone reportable segment under GAAP. The Company’s chief operating decision maker (“CODM”) is its Chief Executive Officer. The Company’s CODM evaluates the segment operating results for performance assessment and resource allocation purposes based upon entity-wide sales and expense information reported in the condensed consolidated statements of income (loss). The primary measure of segment profit (loss) is net income (loss) from continuing operations as reported in the condensed consolidated statements of income (loss). Significant segment expense categories evaluated by the CODM include cost of goods sold, selling, general and administrative expenses, and the other line items reported in the condensed consolidated statements of income (loss). As the Company has a single reportable segment, assets are reported in the condensed consolidated balance sheets and capital expenditures are reported in the condensed consolidated statements of cash flows.

17. Stock-Based Compensation:

The Company has an equity incentive plan under which it grants common stock awards to employees, directors and affiliates of the Company. At September 30, 2026,7,129,344 shares of common stock were available for issuance under the plan. The Company settles these awards through the issuance of treasury shares under its equity incentive plan. The Company has granted RSAs, RSUs and PSUs as part of its equity incentive compensation program.

Modifications

The cumulative Adjusted EBITDA goals for the outstanding PSUs with performance periods from January 1, 2024 through December 31, 2026, and January 1, 2025 through December 31, 2027 included anticipated contributions from the Advanced Materials & Catalysts business and ceased to provide meaningful metrics on which the Company’s performance during the remainder of the performance periods could be assessed. During the quarter ended March 31, 2026, the Compensation Committee of the Company’s Board (“Compensation Committee”) determined that the cumulative Adjusted EBITDA goals from January 1, 2026 onwards would be adjusted based on applying the original growth rates at threshold, target and maximum to the 2025 continuing operations Adjusted EBITDA. Actual performance will be similarly calculated following the conclusion of thethree-year performance periods. No adjustments were made to the three-year relative total shareholder return (“TSR”) goals. The modifications resulted in incremental stock-based compensation expense during the nine months ended September 30, 2026 which was not material.

Restricted Stock Awards, Restricted Stock Units and Performance Stock Units

RSU

During the nine months ended September 30, 2026, the Company granted 682,526 RSUs under its equity incentive plan. Each RSU provides the recipient with the right to receive a share of common stock subject to graded vesting terms based on service, which for the awards granted during the nine months ended September 30, 2026, generally requires approximatelyone year of service for members of the Company’s Board and approximately three years of service for employees. The value of the RSUs granted during the nine months ended September 30, 2026 was based on the average of the high and low trading prices of the Company’s common stock on the NYSE on the preceding trading day, in accordance with the Company’s policy for valuing such awards. Compensation expense related to the RSUs is recognized on a straight-line basis over the respective vesting period.

PSU

2026 Grants

During the nine months ended September 30, 2026, the Company granted 351,870 PSUs (at target) under its equity incentive plan. The PSUs granted during the nine months ended September 30, 2026 provide the recipients with the right to receive shares of common stock dependent on 50% of a Company-specific financial performance target and 50% on the relative increase in the TSR goal (“the Performance measures”). The Performance measures are measured independently of each other, but achievement of both metrics is measured on the same three-year performance period from January 1, 2026 through December 31, 2028 (“Performance period”). Depending on the Company’s performance relative to the Performance measures, each PSU award recipient is eligible to receive a percentage of the target number of shares granted to the recipient, ranging from zero to 200%. The PSUs, to the extent earned, will vest on the date the Compensation Committee certifies the achievement of the Performance measures for the Performance period, which will occur subsequent to the end of the Performance period and after the Company files its annual consolidated financial statements for the year ending December 31, 2028.

Achievement of the Company-specific financial performance target is measured based on the actual three-year cumulative results across the Performance period. The TSR goal is based on the Company’s actual TSR performance against companies in the S&P 1500 Specialty Chemicals Index over the Performance period. The TSR goal, which determines how much of the 50% of the PSUs granted during 2026 may be earned, is considered a market condition as opposed to a vesting condition. Because a market condition is not considered a vesting condition, it is reflected in the grant date fair value of the award and the associated compensation cost based on the fair value of the award is recognized over the Performance period, regardless of whether the Company actually achieves the market condition or the level of achievement, as long as service is provided by the recipient.

The Company used a Monte Carlo simulation to estimate the $15.61 weighted average fair value of the awards granted, subject to the TSR goal during the nine months ended September 30, 2026, with the following weighted average assumptions:

2023 Grants

In March 2026, the Compensation Committee certified the achievement of the performance metrics for thethree-year period ended December 31, 2025, related to the PSUs granted during the year ended December 31, 2023. The PSUs granted during the year ended December 31, 2023 provide the recipients with the right to receive shares of common stock dependent on the achievement of a TSR goal and are generally subject to the provision of service through the vesting date of the award. The TSR goal was based on the Company’s actual TSR percentage increase over the performance period. The awards vested during the nine months ended September 30, 2026 withno percentage of the TSR goal earned.

Award Activity

The following table summarizes the activity for the Company’s RSUs and PSUs for the nine months ended September 30, 2026:

(1)Based on target.

During the nine months ended September 30, 2026, the Company did not grant any RSAs. Cash proceeds received by the Company from the exercise of stock options were not material for the nine months ended September 30, 2026.

Stock-Based Compensation Expense

For the three months ended September 30, 2026 and 2025, stock-based compensation expense for the Company included in continuing operations was $2,423 and $2,271, respectively. The associated income tax benefit based on the applicable statutory rate recognized in the condensed consolidated statements of income (loss) for the three months ended September 30, 2026 and 2025 was $657 and $620, respectively.

For the nine months ended September 30, 2026 and 2025, stock-based compensation expense for the Company included in continuing operations was $8,354 and $7,551, respectively. The associated income tax benefit based on the applicable statutory rate recognized in the condensed consolidated statements of income (loss) for the nine months ended September 30, 2026 and 2025 was $2,266 and $2,063, respectively.

As of September 30, 2026, unrecognized compensation cost of $6,316 for RSUs and $5,254 for PSUs are considered probable of vesting and the weighted-average period over which these costs are expected to be recognized at September 30, 2026 was 1.73 years for the RSUs and 1.96 years for the PSUs.

18. Earnings per Share:

Basic earnings per share is calculated as income available to common stockholders, divided by the weighted average number of common shares outstanding during the period. The weighted average number of common shares outstanding during the period for the computation of basic earnings per share excludes RSAs that have legally been issued but are nonvested during the period, as the sale of these shares is prohibited pending satisfaction of certain vesting conditions by the award recipients in order to earn the rights to the shares.

Diluted earnings per share is calculated as income available to common stockholders, divided by the weighted average number of common and potential common shares outstanding during the period, if dilutive. Potential common shares reflect (1) unvested RSAs and RSUs with service vesting conditions, (2) PSUs with vesting conditions considered probable of achievement and (3) options to purchase common stock, all of which have been included in the diluted earnings per share calculation using the treasury stock method.

The reconciliation from basic to diluted weighted average shares outstanding is as follows:

We utilize the control number concept in the computation of diluted earnings per share to determine whether potential common stock equivalents are dilutive. The control number used is income from continuing operations. The control number concept requires that the same number of potentially dilutive securities applied in computing diluted earnings per share from continuing operations be applied to all other categories of income or loss, regardless of their anti-dilutive effect on such categories.

The Company reported a net loss from continuing operations for the nine months ended September 30, 2025, and therefore excluded the dilutive effect of 521,803 shares, which consisted of unvested common shares, RSUs with service conditions, PSUs considered probable of vesting and assumed stock option exercises and conversions from the computation of weighted average diluted shares outstanding.

Basic and diluted income per share are calculated as follows:

The table below presents the details of the Company’s weighted average equity-based awards outstanding during each respective period that were excluded from the calculation of diluted earnings per share:

Certain stock options to purchase shares of common stock were excluded from the computation of diluted earnings per share for the respective periods because the options’ exercise price was greater than the average market price of the common shares. These stock options and anti-dilutive awards are not included in the dilution calculation, as their inclusion would have the effect of increasing diluted income per share.

19. Supplemental Cash Flow Information:

The following table presents supplemental cash flow information for the Company, which includes activity from both continuing and discontinued operations, except for operating leases which is continuing operations only:

(1)Cash paid for income taxes, net of refunds for the nine months ended September 30, 2026 includes approximately $21,157 related to the purchase of transferable Clean Fuel Production Tax Credits (see Note 13 to these condensed consolidated financial statements for details).

(2)Cash paid for interest is shown net of capitalized interest and includes the cash received or paid on the Company’s interest rate cap agreements designated as cash flow hedges for the periods presented (see Note 12 to these condensed consolidated financial statements for details).

20. Subsequent Events:

The Company has evaluated subsequent events since the balance sheet date and determined that there are no additional items to disclose.