X0508 4/A 2023-11-17 2023-11-20 0000776867 WHITE MOUNTAINS INSURANCE GROUP LTD WTM 0001186549 Hicks Weston M C/O WHITE MOUNTAINS INSURANCE GROUP, LTD 23 SOUTH MAIN STREET, SUITE 3B HANOVER NH 03755 1 0 0 0 0 Common Shares 2023-11-17 4 P 0 52 1476.15 A 1358 D Common Shares 2023-11-17 4 P 0 120 1476.74 A 1478 D Common Shares 2023-11-17 4 P 0 579 1479.88 A 2057 D Common Shares 2023-11-17 4 P 0 11 1483.43 A 2068 D Common Shares 2023-11-17 4 P 0 238 1484.96 A 2306 D The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $1475.51 to $1476.32, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares transacted at each separate price within the ranges set forth in footnotes (1) to (5) of this Form 4. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $1476.55 to $1476.92, inclusive. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $1479.35 to $1480.01, inclusive. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $1483.13 to $1483.78, inclusive. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $1484.28 to $1485.00, inclusive. The footnotes in this report are amended to make clear that all transactions referred to in Table I were purchases. Wesley C. Bell, by Power of Attorney 2023-11-20