X0508 4 2024-12-19 0000354190 Arthur J. Gallagher & Co. AJG 0001589933 GALLAGHER THOMAS JOSEPH 2850 GOLF ROAD ROLLING MEADOWS IL 60008-4002 1 President 0 Common Stock 2024-12-19 4 G 0 840 0 D 328259.045 D Common Stock 62295 I By grantor retained annuity trust Common Stock 66709 I By Irrevocable Trust Common Stock 32428 I By wife Common Stock 118440 I By wife as trustee Common Stock 367.585 I Gallagher 401(k) plan account The reporting person disclaims beneficial ownership of these shares, and this report shall not be deemed an admission that the reporting person is the beneficial owner of these shares for purposes of Section 16 or for any other purpose. These shares are held in trusts, for the benefit of the reporting person's children, of which his wife is a trustee. /s/ Ryan Session, by power of attorney 2024-12-20