署名银行 2025年度报告

(Mark One) ☒ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934For the fiscal year ended December 31, 2025OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934FOR THE TRANSITION PERIOD FROMTO Commission File Number 001-38139 Byline Bancorp, Inc. (Exact name of Registrant as specified in its Charter) 36-3012593(I.R.S. Employer Identification No.) Registrant’s telephone number, including area code: (773) 244-7000 Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. YES☐NO☒Indicate by check mark whether the Registrant: (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the Registrant was required to file such reports), and (2) has been subject to such filing requirements for the past90 days. YES☒NO☐Indicate by check mark whether the Registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S- T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the Registrant was required to submit such files). YES☒NO☐Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 ofthe Exchange Act. Large accelerated filer☒Accelerated filer☐Emerging growth companyNon-accelerated filer☐Smaller reporting company☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revisedfinancial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-OxleyAct (15 U.S.C. 7262(b))by the registered public accounting firm that prepared or issued its audit report☒If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.☐Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b).☐Indicate by check mark whether the Registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). YES☐NO☒ The aggregate market value of the voting and non-voting common equity held by non-affiliates of the Registrant, based on the closing price of the Registrant’s The number of shares of Registrant’s common stock outstanding as of February 24, 2026 was 45,590,691.Portions of the Registrant’s Definitive Proxy Statement relating to its 2026 Annual Meeting of Stockholders, scheduled to be held on June 2, 2026, are incorporated by reference into Part III of this Report. Table of Contents PART I Item 1.BusinessItem 1A.Risk FactorsItem 1B.Unresolved Staff CommentsItem 1C.CybersecurityItem 2.PropertiesItem 3.Legal ProceedingsItem 4.Mine Safety Disclosures PART II Item 5.Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of EquitySecurities32Item 6.[Reserved]33Item 7.Management’s Discussion and Analysis of Financial Condition and Results of Operations34Item 7A.Quantitative and Qualitative Disclosures About Market Risk63Item 8.Financial Statements and Supplementary Data65Item 9.Changes in and Disagreements With Accountants on Accounting and Financial Disclosure125Item 9A.Controls and Procedures125Item 9B.Other Information125Item 9C.Disclosure Regarding Foreign Jurisdictions that Prevent Inspections125 PART III Item 10.Directors, Executive Officers and Corporate Governance126Item 11.Executive Compensation126Item 12.Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters127Item 13.Certain Relationships and Related Transactions, and Director Independence127Item 14.Principal Accounting Fees and Services127 PART IV Item 15.Exhibits and Financial Statement SchedulesItem 16.Form 10-K SummarySignatures 128129130 Table of Contents Special Note Regarding Forward-Looking Statements Statements contained in this report and in other documents we file with or furnish to the Securities and Exchange Commission(“SEC”) that are not historical facts may constitute “forward-looking statements” within the meaning of the U.S. Private SecuritiesLi