STEPAN CO

Report of Independent Regist ered Public Accounting Firm

To the stockholders and the Board of Directors of Stepan Company

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Stepan Company and subsidiaries (the “Company”) as of December 31, 2025 and 2024, the related consolidated statements of income, comprehensive income, stockholders’ equity, and cash flows, for each of the three years in the period ended December 31, 2025, and the related notes (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2025, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company’s internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 26, 2026, expressed an unqualified opinion on the Company’s internal control over financial reporting.

Basis for Opinion

These financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Goodwill — European Polymers— Refer to Notes 1 and Note 4 to the Financial Statements

Critical Audit Matter Description

The Company's goodwill for its reporting units is tested annually for impairment during the second quarter of each year, and more frequently if events and circumstances indicate that the assets might be impaired. The Company's evaluation of its goodwill for impairment involves the comparison of the fair value of the reporting units to its carrying value.

The Company elected to use a quantitative approach to determine the fair value of the Stepan European Polymers reporting unit based upon the income method and the market-based method based on EBITDA multiples to determine the fair value of its reporting unit. The fair value determination using the discounted cash flow method requires management to make significant estimates and assumptions related to forecasts of future revenues and earnings before interest, taxes, depreciation, and amortization (EBITDA) and the discount rate. The determination of the fair value using the market-based method requires management to make assumptions related to marketplace EBITDA multiples from within a peer public company group. The goodwill balance allocated to the European Polymers reporting unit was $47.0 million at December 31, 2025. The European Polymers reporting unit goodwill is included in the Company’s goodwill balance of $92.8 million at December 31, 2025. The fair value of the European Polymers reporting unit was greater than its carrying value as of the measurement date, and as a result, management did not record an impairment charge related to the reporting unit goodwill.

Given the significant judgments made by management to estimate the fair value of the European Polymers reporting unit, performing audit procedures to evaluate the reasonableness of management's estimates and assumptions related to forecasts of future EBITDA, as well as the calculation of the discount rate and the selection of multiples applied to management's forecasted EBITDA estimates for the European Polymers reporting unit, required a high degree of auditor judgment and an increased extent of effort, including the need to involve our fair value specialists.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the fair value of the goodwill discussed above included the following, among others:

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We tested the effectiveness of controls over the goodwill impairment evaluations, including those over the appropriateness of the valuation methodology, forecast of EBITDA, and selection of the discount rate for the reporting unit.

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We performed a sensitivity analysis of the business and valuation assumptions which included their impact on the income and market approach.

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With the assistance of our internal fair value specialists, we evaluated the reasonableness of the valuation methodology, and discount rate:

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Testing the mathematical accuracy of the calculations.

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Testing the source information underlying the determination of the discount rate and EBITDA multiples.

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Developing ranges of independent estimates and comparing those to the rates selected by management.

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We assessed the reasonableness of management’s forecast of future EBITDA by comparing the projections to historical results, forecasted information included in macroeconomic benchmarking reports and certain peer companies. We also evaluated whether the estimated future cash flows were consistent with evidence obtained in other areas of the audit.

/s/ Deloitte & Touche LLP

DELOITTE & TOUCHE LLP

Chicago, Illinois

We have served as the Company’s auditor since 2002.