SIERRA BANCORP

Report of Independent Registered Public Accounting Firm

To the Shareholders and the Board of Directors

Sierra Bancorp and Subsidiary

Opinions on the Consolidated Financial Statements and Internal Control Over Financial Reporting

We have audited the accompanying consolidated balance sheet of Sierra Bancorp and its wholly owned subsidiary (the “Company”) as of December 31, 2025, the related consolidated statements of income, comprehensive (loss) income, changes in shareholders’ equity, and cash flows for the year ended December 31, 2025, and the related notes (collectively referred to as the “financial statements”). We also have audited the Company’s internal control over financial reporting as of December 31, 2025, based on criteria established inInternal Control – Integrated Framework: (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2025, and the results of its operations and its cash flows for the year ended December 31, 2025, in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2025, based on criteria established inInternal Control – Integrated Framework: (2013) issued by COSO.

Basis for Opinion

The Company’s management is responsible for these financial statements, for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management’s Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s financial statements and an opinion on the Company’s internal control over financial reporting based on our audits.

We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (“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 audits to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects.

Our audit of the financial statements 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 include examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audit also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions.

Definitions and Limitations of Internal Control Over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of reliable financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions or that the degree of compliance with the policies or procedures may deteriorate.

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 a critical audit matter 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.

Allowance for Credit Losses – Loans

As of December 31, 2025, the Company’s allowance for credit losses (“ACL”) totaled $21.5 million. The Company calculates its ACL in accordance with Topic 326,Financial Instruments – Credit Losses. As described in Notes 2 and 4 to the consolidated financial statements, the ACL for loans is separated between a collective reserve evaluation, for loans where similar risk characteristics exist, and an individual reserve evaluation for loans without similar risk characteristics. The collective quantitative ACL for loans is estimated using the remaining life or discounted cash flow (“DCF”) methodology based on the loan portfolio segment. In addition, for the collective reserve, management utilizes qualitative factors to adjust for current and expected conditions not captured within the quantitative loss estimates.

The qualitative reserve is calculated using a combination of numeric frameworks and management judgement to determine risk categorizations in each of the qualitative factors. The amount of qualitative reserves is also contingent upon the historical peer, life-of-loan equivalent, loss rate ranges and the relative weighting of qualitative factors.

We identified the Company’s estimate of the ACL, and more specifically the qualitative factor adjustments applied in the ACL, as a critical audit matter. The principal consideration for our determination is the subjectivity and judgment involved in management’s determination of credit loss estimates and assumptions (segment risk rating assigned), specifically for management’s determination of the changes in value of underlying collateral qualitative factor adjustment, management’s determination of the loan category and concentrations qualitative factor adjustment, and management’s determination of the use of peer loss/default levels in the DCF regression analysis qualitative factor assigned to each loan segment. Auditing these assumptions required increased auditor effort and a high degree of auditor subjectivity and judgment.

The primary procedures we performed to address this critical audit matter included:

*/s/*Forvis Mazars, LLP

We have served as the Company’s auditor since 2025.

Denver, Colorado** **

February 27, 2026