MBG INVESTORS I, L.P. sold BY

Footnotes

Sale to and repurchase by Byline Bancorp, Inc. ("the Issuer") of 300,000 shares of Common Stock (the "Shares") pursuant to a Stock Repurchase Agreement (the "Stock Repurchase Agreement") dated as of August 7, 2026 between MBG Investors I, L.P. and the Issuer. Under the Stock Repurchase Agreement, the Issuer agreed to purchase the Shares at a price of $39.10 per Share, which price was determined based on the five (5) day average closing price for the Common Stock on the NYSE for the period from July 27, 2026 through July 31, 2026.; Mr. Antonio del Valle Perochena is the general partner of MBG Investors I, L.P. and possesses sole voting and investment power with respect to the shares of common stock held by MBG Investors I, L.P. Mr. del Valle Perochena owns 16.68% of the partnership interests of MBG Investors I, L.P. Mr. del Valle Perochena disclaims beneficial ownership of such shares of common stock except to the extent of his pecuniary interest therein, and this report shall not be deemed an admission that he is the beneficial owner of such disclaimed shares of common stock for purposes of Section 16 or for any other purpose. The address for MBG Investors I, L.P. is 365 Bay Street, Suite 800, M5H2V1 Toronto, Ontario, Canada.