Transaction Details

Footnotes

This report discloses a sale of shares to cover tax obligations relating to the distribution of 35,739 deferred shares under the company's Supplemental Savings and Thrift Plan (reported on August 4, 2025). In lieu of withholding for taxes, the reporting person was required to receive the full distribution of shares and subsequently sell a portion of such shares to cover his tax obligation. | The price reported is an average weighted price. The shares were sold in multiple transactions on 12/22/2025 at prices ranging from $257.730 to $258.250. 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. | In the past, Common Stock and Common Stock (Restricted) were reported as two separate line items. In the future, they will be reported as a combined total as is stated on this Form. | The reporting person has no voting or invesment power over these shares and disclaims beneficial ownership. | Each notional stock unit represents a right to receive one share of Gallagher common stock. | The notional stock units become payable following the reporting person's separation from service with Gallagher. | 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. | One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. | Closing price of Gallagher common stock on February 28, 2025. | One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. | One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. | 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.