144 0001368185 XXXXXXXX LIVE 0001702750 Byline Bancorp 001-38139 180 North LaSalle Street Suite 300 Chicago IL 60601 (773) 244-7000 Brogan Ptacin Director Common UBS Financial Services Inc

1000 Harbor Blvd 3rd Floor Weehawken NJ 07086

8100 244000 44385204 11/07/2024 NYSE Common 06/09/2018 Merger Byline Bancorp N 31134 06/09/2018 n/a Y selling under the Brogan M. Ptacin Rev Trust DTD 03/24/2004 Brogan M. Ptacin TTEE and the client Brogan Ptacin is director at Byline 11/07/2024 /s/ UBS Financial Services Inc, as attorney-in-fact for Brogan Ptacin