ACNB CORP

Shareholders and the Board of Directors of ACNB Corporation

Gettysburg, Pennsylvania

Opinions on the Financial Statements and Internal Control over Financial Reporting

We have audited the accompanying consolidated statements of condition of ACNB Corporation (the "Company") as of December 31, 2025 and 2024, the related consolidated statements of income, comprehensive income, changes in stockholders’ equity, and cash flows for each of the years in the three-year period 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 in Internal Control – Integrated Framework: (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

In our opinion, the financial statements referred to above 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 years in the three-year period 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 in Internal Control – Integrated Framework: (2013) issued by COSO.

Basis for Opinions

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 audits 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 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. 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.

Definition 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 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 Matters

The critical audit matters communicated below are matters arising from the current period audit of the financial statements that were communicated or required to be communicated to the audit committee and that: (1) relate to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of the 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 matters below, providing a separate opinion on the critical audit matters or on the accounts or disclosures to which they relate.

Allowance for Credit Losses on Loans

As described in Notes 1 and 5, the Company’s methodology for estimating the allowance for credit losses on loans includes quantitative and qualitative components of the calculation. The Company’s loan portfolio is segmented by loan types that behave similarly during economic cycles. The quantitative analysis includes using a discounted cash flow (DCF) model for determining the allowance for credit losses. Economic forecasts are used in the model to estimate the probability of default and loss given default through regression which are key inputs into the DCF model calculation. Quantitative model assumptions include, but are not limited to the discount rate, prepayment speeds, and curtailments. The quantitative model output is adjusted with qualitative adjustments. Management develops a qualitative framework that serves as the basis for determining the reasonableness of the model’s output and makes qualitative adjustments as necessary. The allowance methodology is inherently complex and requires the use of significant management judgment.

We determined that auditing the allowance for credit losses on loans was a critical audit matter because of the extent of auditor judgment applied and significant audit effort to evaluate the significant subjective and complex judgments made by management, including segmentation, the economic forecasts used to calculate the regressions within the DCF model, the quantitative model assumptions as mentioned above, and the qualitative adjustments made using the qualitative framework. In addition, we used individuals with specialized skill or knowledge to assist us in auditing the judgments made by management.

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

•Tested the operating effectiveness of the Company’s controls that addressed the following:

◦Management’s selection and application of the DCF model, including the evaluation of the reasonableness of the segmentation, the reasonable and supportable economic forecasts, the significant model assumptions, and the relevance and reliability of data used in the model, and the validation of the DCF model outputs.

◦Management’s review of the appropriateness of the qualitative framework, the reasonableness of significant assumptions applied, the relevance and reliability of data used in the qualitative adjustments, and the mathematical accuracy of the qualitative adjustments calculation.

•Evaluated the reasonableness of management’s judgments related to the selection of the segmentation, DCF model, the reasonable and supportable economic forecasts, the significant model assumptions, and the relevance and reliability of the data used in the DCF model.

•Tested the mathematical accuracy and application of the DCF model including engaging individuals with specialized skills in to validate the DCF model outputs.

•Evaluated the reasonableness of qualitative adjustments, including evaluating the appropriateness of the qualitative framework, the assumptions and judgments applied in the determination of the qualitative adjustments, the relevance and reliability of data used in the qualitative adjustments, and the mathematical accuracy of the qualitative adjustments calculation.

Business Combination – Fair Value of Acquired Loans

As described in Notes 1 and 2, during 2025, the Company completed the acquisition of Traditions Bancorp, Inc. for stock and cash consideration totaling approximately $83.8 million on February 1, 2025. Accounting for an acquisition requires management to record the assets acquired and liabilities assumed at fair value as of the date of acquisition. The estimation of fair values related to acquired loans required management to make significant judgments and assumptions. The acquired loans were recorded at $648.5 million. The determination of fair values over acquired loans involves significant judgment by management regarding methods and assumptions, including discount rates, default rates, and repayment rates. For acquired loans at the merger date, management evaluated and classified loans based upon whether the loans had experienced a more-than-insignificant amount of credit deteriorating since origination. The factors considered in evaluating more-than-insignificant credit deterioration included, but not limited to, loans 30 days or more past due, loans with an internal risk grade below average or lower, or loans classified as non-accrual.

We identified auditing the fair value of acquired loans as a critical audit matter because it involved especially subjective auditor judgment and audit effort to evaluate the significant judgments made by management, including the need for professionals with specialized skill or knowledge.

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

•Tested the operating effectiveness of the Company’s controls that addressed the following:

◦Evaluation of the appropriateness of methods and assumptions applied in the estimate of fair value over the acquired loans.

◦Identification of acquired loans that had experienced more-than-insignificant amount of credit deterioration.

◦Evaluation of the relevance and reliability of external data used in the valuation of acquired loans.

◦Completeness and accuracy of loan data used in the valuation of acquired loans.

•Substantively test the estimate of the fair value of acquired loans, including developing independent expectations and applying those independently developed significant assumptions in the calculation with the assistance of professionals with specialized skill and knowledge.

•Evaluation of the relevance and reliability of external data used in the valuation of acquired loans.

•Evaluation of criteria used to identify the population of loans that had experienced a more-than-insignificant amount of credit deterioration since origination and completeness of population.

•Testing the completeness and accuracy of loan data used in the calculation.

/s/ Crowe LLP

We have served as the Company’s auditor since 2022.

Franklin, Tennessee

March 12, 2026