White Mountains Insurance Group Ltd. has unanimously elected Liam Caffrey as chief executive officer, effective Jan. 1, 2026. He will also join the White Mountains Board at that time.

Caffrey will succeed current CEO Manning Rountree, who will retire on Dec. 31, 2025. Rountree will serve as a senior advisor to White Mountains through Jan. 1, 2028.

Caffrey, who currently serves as president and chief financial officer, joined White Mountains as CFO in 2022. Prior to that, he spent nine years in various finance and operating roles at Aon PLC and earlier served as a principal at McKinsey & Company.

Michael Papamichael, currently managing director and deputy CFO of White Mountains Capital LLC, will succeed Caffrey as CFO. Prior to rejoining White Mountains in 2020, Papamichael had served as a senior vice president at Hamilton Insurance Group since 2018. Prior to joining Hamilton, he held various senior positions at Sirius Group, including when it was owned by White Mountains prior to 2016.

Giles Harrison, currently executive vice president and chief strategy officer, will become president of White Mountains. Harrison joined White Mountains in June 2024. Prior to that, he worked for the Zurich Insurance Group, most recently as the CFO of Farmers Group.