X0508 4 2025-03-28 0000944695 HANOVER INSURANCE GROUP, INC. THG 0001428157 Roche John C C/O THE HANOVER INSURANCE GROUP, INC. 440 LINCOLN STREET WORCESTER MA 01653 1 1 0 0 President and CEO 1 Common Stock 2025-03-28 4 M 0 400 77.91 A 124677.851 D Common Stock 2025-03-28 4 S 0 400 175.03 D 124277.851 D Common Stock 2025-03-28 4 A 0 135.857 0 A 124413.708 D Common Stock 2025-03-31 4 M 0 301 77.91 A 124714.708 D Common Stock 2025-03-31 4 S 0 301 175 D 124413.708 D Common Stock Option (right to buy) 77.91 2025-03-28 4 M 0 400 0 D 2026-02-23 Common Stock 400 9207 D Common Stock Option (right to buy) 77.91 2025-03-31 4 M 0 301 0 D 2026-02-23 Common Stock 301 8906 D Exercise of options scheduled to expire in February 2026 and resulting sale of shares reported were effected pursuant to a pre-established Rule 10b5-1 Trading Plan adopted on November 5, 2024. Does not include 14,454 shares held by the Reporting Person's spouse. Grant of restricted stock units ("RSUs") under the Issuer's 2022 Long-Term Incentive Plan ("2022 LTIP") in connection with the accrual of dividend equivalent rights associated with RSUs previously granted under the Issuer's 2022 LTIP. Such RSUs vest on the third anniversary of the date of grant of the original underlying RSUs. The option, representing the right to purchase a total of 21,413 shares, vested 1/3 on each of 2/23/17, 2/23/18 and 2/23/19. /s/ Lindsay L. Katz pursuant to Confirming Statement 2025-04-01