1ST SOURCE CORP

Report of Independent Registered Public Accounting Firm

Shareholders, Board of Directors and Audit, Finance, and Risk Committee

Opinion on the Consolidated Financial Statements

We have audited the accompanying consolidated statements of financial condition of 1st Source Corporation (the “Company”) as of December 31, 2025 and 2024, the related consolidated statements of income, comprehensive income (loss), shareholders’ 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”). 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.

We also have 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 17, 2026, expressed an unqualified opinion thereon.

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 audits 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 include 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 the 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 Loan and Lease Losses – Qualitative Factors

Description of the Critical Audit Matter

As presented in Note 5 to the financial statements, the Company’s allowance for loan and lease losses (ALLL) was $161.8 million at December 31, 2025. As described in Note 1 to the financial statements, the ALLL is an estimate of current expected credit losses in the loan and lease portfolio. The determination of the ALLL requires significant judgment reflecting the Company’s estimate of expected future losses for the loan’s entire contractual term adjusted for expected payments when appropriate.

The Company categorizes its loan portfolios into nine segments based on similar risk characteristics. Loans within each segment are collectively evaluated using either: 1) a cohort cumulative loss rate methodology (“cohort”) or, 2) the probability of default (“PD”)/loss given default (“LGD”) methodology (PD/LGD). For both the cohort and the PD/LGD methodologies, the Company uses qualitative adjustments to capture differences that may exist between the current and historical conditions. Qualitative factors include but are not limited to current market risk assessment by industry, recent loss experience in particular segments of the portfolios, movement in equipment values collateralizing specialized industry portfolios, concentrations of credit risk, delinquencies, trends in volume, experience and depth of relationship managers and division management, and the effects of changes in lending policies and practices, including changes in quality of the loan and lease origination, servicing, and risk management process.

We identified the qualitative factor adjustments included in the ALLL as a critical audit matter. The principal considerations for our determination included the high degree of judgment and subjectivity in auditing management’s estimation of qualitative factor adjustments, which requires significant judgment.

How the Critical Audit Matter Was Addressed in the Audit

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

•Tested the design and operating effectiveness of internal controls over the establishment of qualitative adjustments for current and expected conditions.

•Evaluated the current and expected qualitative adjustments, including assessing the basis for the adjustments and the reasonableness of the significant assumptions related to loan portfolio policies and underwriting, credit quality metrics, concentrations, as well as external market data including gross domestic product, unemployment rates, and housing market trends.

•Tested the completeness and accuracy and evaluated the relevance of the key data used as inputs to the qualitative adjustment estimation process, including relevant external market data, portfolio segment loan balances and other loan-specific data.

/s/ Forvis Mazars, LLP

We have served as the Company’s auditor since 2015.

Fort Wayne, Indiana

February 17, 2026

Report of Independent Registered Public Accounting Firm

Shareholders, Board of Directors and Audit, Finance, and Risk Committee

Opinion on the Internal Control over Financial Reporting

We have audited 1st Source Corporation’s (the “Company”) 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 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.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (“PCAOB”), the consolidated financial statements of the Company as of December 31, 2025 and 2024, and for each of the three years in the period ended December 31, 2025, and our report dated February 17, 2026, expressed an unqualified opinion on those financial statements.

Basis for Opinion

The Company’s management is responsible 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 Report. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit.

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 audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects. Our audit 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 audit also included performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

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.

/s/ Forvis Mazars, LLP

Fort Wayne, Indiana

February 17, 2026