BYLINE BANCORP, INC.

Report of Independent Registered Public Accounting Firm

To the Stockholders and the Board of Directors of

Byline Bancorp, Inc. and Subsidiaries

Opinions on the Financial Statements and Internal Control over Financial Reporting

We have audited the accompanying consolidated statements of financial condition of Byline Bancorp, Inc. and Subsidiaries (the “Company”) as of December 31, 2025 and 2024, the related consolidated statements of operations, comprehensive income (loss), changes in 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 “consolidated 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, theconsolidated financial statements referred to above present fairly, in all material respects, the consolidated financial position of the Company as of December 31, 2025 and 2024, and the consolidated 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. 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 consolidated 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 Annual Report on Effectiveness of Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s consolidated 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 theconsolidated 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 theconsolidated financial statements included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures to respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in theconsolidated 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 theconsolidated 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 Matter

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated 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 consolidated 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 consolidated 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 – Loan Risk Ratings, Qualitative Factors, and Individually Evaluated Loans

Critical Audit Matter Description

As described in Notes 1 and 5 to the consolidated financial statements, the Company’s allowance for credit losses for loans and leases was $109 million as of December 31, 2025. The allowance for credit losses, which is an estimate of expected credit losses over the contractual life of an instrument, is developed using internal and external data based on historical experience, current conditions, and reasonable and supportable forecasts. This balance acts as a valuation account that is deducted from the amortized cost basis of loans and leases to present the net carrying value expected to be collected by the Company. We identified management’s risk rating of loans, the determination of qualitative factor adjustments, and the calculation of reserves on individually evaluated loans, all of which are used in the development of an allowance for credit losses estimate, as a critical audit matter.

Our principal consideration in determining that components of the allowance for credit losses for loans and leases are a critical audit matter is the significant judgement that management exercises in developing the estimate, particularly in relation to the risk rating of loans, the determination of qualitative factor adjustments, and the calculation of reserves on individually evaluated loans. The quantitative reserve on collectively evaluated loans incorporates loan risk ratings as a significant input. Risk ratings are applied to individual credits and the determination requires judgment based on a variety of factors, some of which are subjective. For collectively evaluated loans, the Company also applies qualitative factor adjustments to account for risks that are not reflected in the historical loss history, which requires judgement and is inherently subjective. Lastly, management calculates a reserve on individually evaluated loans based on sources of repayment and the net realizable value of collateral, which requires judgment to determine. The degree of management judgement and subjectivity involved in determining those specific components of the allowance estimate resulted in an especially high level of auditor judgment, subjectivity, and/or effort in performing audit procedures and evaluating the results of those audit procedures in connection with forming our overall opinion on the consolidated financial statements.

How We Addressed the Matter in Our Audit

Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included evaluating the design and testing the operating effectiveness of internal controls related to the Company’s calculation of the allowance for credit losses for loans and leases, including controls over loan risk ratings, the evaluation of qualitative factors, and the calculation of the loss reserves associated with individually evaluated loans. Our audit procedures related to the critical audit matter included the following, among others:

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Evaluating the appropriateness of the Company’s loan risk rating policy and testing a risk-based targeted selection of loans to ensure that the Company is appropriately classifying loans and leases by risk category.

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For individually evaluated loans, evaluating the reasonableness of the allowance recognized, including the testing of selected collateral values with the assistance of internal valuation specialists.

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Evaluating the reasonableness and appropriateness of the qualitative factor adjustments by obtaining management’s analysis and testing selected assumptions and data used to develop the qualitative factors.

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Testing the completeness and accuracy of the data used in, and the mathematical accuracy and computation of, the allowance for credit losses for loans and leases by reperforming or independently calculating significant elements of the allowance, including quantitative historical loss factors applied to the loan and lease segments based on risk ratings and utilizing relevant source documents.

/s/ Baker Tilly US, LLP

Portland, Oregon

February 27, 2026

We have served as the Company’s auditor since 2013.