X0508 4 2024-10-30 0000354190 Arthur J. Gallagher & Co. AJG 0001186006 GALLAGHER J PATRICK JR 2850 GOLF ROAD ROLLING MEADOWS IL 60008-4002 1 1 CEO 0 Common Stock 2024-10-30 4 G 0 10065 0 D 66703 I By Irrevocable Trust Common Stock 23448 I By Spouse's Trust Common Stock 146945.3028 D Common Stock 255965 I By Corporation Common Stock 271525 I By Spouse Common Stock 219655 I By Trust Common Stock 367.584 I Gallagher 401(k) plan account Shares held in trust for the benefit of my children of which I am sole Trustee. Shares held in revocable trust of which my spouse is sole Trustee and as to which I disclaim beneficial ownership. Held in trust for benefit of children. /s/ Ryan Session, by power of attorney 2024-11-01