Simpson Manufacturing Co., Inc.

Disclosure Controls and Procedures. As of December 31, 2025, the Company carried out an evaluation, under the supervision and with the participation of the Company’s management, including the chief executive officer the (“CEO”) and the chief financial officer (the “CFO”), of the effectiveness of the Company’s disclosure controls and procedures (as defined in Rule 13a-15(e) and 15-d-15(e) under the Exchange Act). Based on this evaluation, the Company’s CEO and CFO have concluded that the Company’s disclosure controls and procedures were effective at a reasonable assurance level. Disclosure controls and procedures are controls and other procedures designed reasonably to assure that information required to be disclosed in the Company’s reports filed or submitted under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures are also designed reasonably to assure that this information is accumulated and communicated to the Company’s management, including the CEO and the CFO, as appropriate to allow timely decisions regarding required disclosure.

The Company’s management, including the CEO and the CFO, does not, however, expect that the Company’s disclosure controls and procedures or the Company’s internal control over financial reporting will prevent all fraud and material errors. Internal control over financial reporting, no matter how well conceived and operated, can provide only reasonable, not absolute assurance that the objectives of the control system are met. In addition, the design of a control system must reflect the fact that there are resource constraints and that the benefits of controls must be considered relative to their costs. The inherent limitations in internal control over financial reporting include the realities that judgments can be faulty and that breakdowns can occur because of simple errors or mistakes. Controls also can be circumvented by the individual acts of some persons, by collusion of two or more people, or by management override of controls. The design of any system of internal control is also based in part on assumptions about the likelihood of future events, and there can be only reasonable, not absolute assurance that any design will succeed in achieving its stated goals under all potential events and conditions. Over time, controls may become inadequate because of changes in circumstances, or the degree of compliance with the policies and procedures may deteriorate.

Management’s Report on Internal Control over Financial Reporting. The Company’s management is responsible for establishing and maintaining adequate internal control over financial reporting. The Company’s management assessed the effectiveness of the Company’s internal control over financial reporting as of December 31, 2025, using the criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (“COSO”) and concluded that the Company’s internal control over financial reporting was effective as of December 31, 2025.

Grant Thornton LLP, an independent registered public accounting firm that audited the Company’s Consolidated Financial Statements, has also audited the effectiveness of the Company’s internal control over financial reporting as of December 31, 2025, as stated in their report included in the Company’s Consolidated Financial Statements.

There were no changes in our internal control over financial reporting identified in management's evaluation pursuant to Rules 13a-15(d) or 15d-15(d) of the Exchange Act during the year ended December 31, 2025, that materially affected, or are reasonably likely to materially affect, the Company's internal control over financial reporting.