Exhibit 99.1 Byline Bancorp, Inc. Reports Third Quarter 2026 Financial Results Net income of $41.8 million, $0.94 diluted earnings per share Chicago, IL, October 22, 2026 – Byline Bancorp, Inc. (NYSE: BY), today reported: | | | | At or for the quarter | | | Third Quarter Highlights | | --- | --- | --- | --- | --- | --- | --- | | | | 3Q26 | 2Q26 | 3Q25 | | (compared to 2Q26 unless specified) | | Financial Results ($$ in thousands) | | | | | | • Delivered record total revenue of $$121.0 | | | | | | | million, | ...