X0508 4 2024-02-26 0000944695 HANOVER INSURANCE GROUP, INC. THG 0001709075 Salvatore Bryan J C/O THE HANOVER INSURANCE GROUP, INC. 440 LINCOLN STREET WORCESTER MA 01653 0 1 0 0 Executive Vice President 0 Common Stock 2024-02-26 4 A 0 1694 0 A 22146.362 D Common Stock 2024-02-26 4 A 0 1175 0 A 23321.362 D Common Stock 2024-02-26 4 F 0 1700 134.610 D 21621.938 D Common Stock 2024-02-27 4 A 0 1863 0 A 23484.938 D Common Stock Option (right to buy) 134.26 2024-02-27 4 A 0 8288 0 A 2034-02-27 Common Stock 8288 8288 D On February 26, 2021, the Reporting Person was granted performance-based restricted stock units ("PBRSUs") pursuant to the Issuer's 2014 Long-Term Incentive Plan. These PBRSUs were subject to a performance-based vesting condition related to three-year average adjusted return on equity and a three-year time-based vesting condition, and also provided for the accumulation of dividend equivalent rights. On February 26, 2024, the performance condition for this award was certified at 112% of the target award (as adjusted for accumulated dividend equivalent rights), and vested and was paid. On February 26, 2021, the Reporting Person was granted PBRSUs pursuant to the Issuer's 2014 Long-Term Incentive Plan. These PBRSUs were subject to a performance-based vesting condition related to three-year relative total shareholder return and a three-year time-based vesting condition, and also provided for the accumulation of dividend equivalent rights. On February 26, 2024, the performance condition for this award was certified at 72.73% of the target award (as adjusted for accumulated dividend equivalent rights), and vested and was paid. Represents shares that were forfeited to pay withholding taxes upon the vesting of restricted stock units that were previously granted by the Issuer and vested on February 26, 2024. In connection with vesting, any fractional shares were rounded up to the next whole share in accordance with the terms of the award agreement. Grant of restricted stock units under the Issuer's 2022 Long-Term Incentive Plan. Such units vest on the third anniversary of the date of grant. Such options vest as to one-third of the shares on each of the first three anniversaries of the grant date. /s/ Lindsay L. Katz pursuant to Confirming Statement 2024-02-28