144 0001663281 XXXXXXXX LIVE 0000929008 WESCO INTERNATIONAL INC 001-14989 225 WEST STATION SQUARE DRIVE STE 700 PITTSBURGH PA 15219 4124542200 Green Equity Investors VII, L.P. Former 10% Stockholder Common Stock Merrill Lynch, Pierce, Fenner & Smith Inc.

555 California Street, 18th Floor San Francisco CA 94104

657180 116222283.00 50827576 05/29/2024 NYSE Common Stock 07/10/2020 The shares of common stock were acquired in the open market NA N 2612719 07/10/2020 The shares of common stock were acquired in the open market N Green Equity Investors VII, L.P.

11111 Santa Monica Blvd., Suite 2000 Los Angeles CA 90025

Common Stock 05/07/2024 802150 138787993.00 Green Equity Investors VII, L.P.

11111 Santa Monica Blvd., Suite 2000 Los Angeles CA 90025

Common Stock 05/15/2024 458372 83423704.00 05/29/2024 Andrew C. Goldberg, Senior VP, General Counsel and Secretary of GEI Capital VII, LLC, general partner of Green Equity Investors VII, L.P.