Transaction Details

Footnotes

The price reported is an average weighted price. The shares were sold in multiple transactions on 9/19/2025 at prices ranging from $298.040 to $298.990. The reporting person will provide to the Securities and Exchange Commission staff, the issuer, or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in the footnotes to this Form 4. | The price reported is an average weighted price. The shares were sold in multiple transactions on 9/19/2025 at prices ranging from $299.100 to $299.950. The reporting person will provide to the Securities and Exchange Commission staff, the issuer, or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in the footnotes to this Form 4. | The price reported is an average weighted price. The shares were sold in multiple transactions on 9/22/2025 at prices ranging from $298.780 to $299.770. The reporting person will provide to the Securities and Exchange Commission staff, the issuer, or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in the footnotes to this Form 4. | The price reported is an average weighted price. The shares were sold in multiple transactions on 9/22/2025 at prices ranging from $299.790 to $299.940. The reporting person will provide to the Securities and Exchange Commission staff, the issuer, or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in the footnotes to this Form 4. | The reporting person has no voting or invesment power over these shares and disclaims beneficial ownership. | Each share of phantom stock represents a right to receive one share of Gallagher common stock. | These shares represent awards under the Age 62 Plan, a nonqualified deferred compensation plan of the Company, which have been deemed invested in Company common stock at the election of the reporting person. Participants vest in these awards when they attain age 62, or after a one-year period for participants who have attained age 61. | Each notional stock unit represents a right to receive one share of Gallagher common stock. | Portions of these notional stock units are payable to the reporting person in shares of common stock in July of 2026, 2028 and 2029 and following the reporting person's separation from service.