White Mountains Insurance Group Ltd
WTM- Exchange
- NYSE
- Industry
- Fire, Marine & Casualty Insurance
- SEC CIK
- 0000776867
No open-market purchases or sales by White Mountains Insurance Group Ltd insiders were filed in the last 90 days; 356 institutions reported holding it in 13F filings for Q2 2026, worth $4.57B in total; Southeastern Asset Management (Longleaf) is the only superinvestor holding it.
Superinvestors holding WTM, Q2 2026
1 superinvestor reports holding White Mountains Insurance Group Ltd on Form 13F, worth $35.5M in total. Weight is White Mountains Insurance Group Ltd's share of each 13F portfolio; actions compare shares with Q1 2026.
| Superinvestor | % of portfolio | Shares | Value | vs. previous quarter |
|---|---|---|---|---|
| Southeastern Asset Management (Longleaf)Mason Hawkins | 1.8% | 17,104 | $35.5M | Reduced−9.3% |
Moves by quarter
Superinvestors that opened, added to, trimmed or sold out of WTM each quarter, comparing shares with the quarter before. A superinvestor that didn't file for a quarter isn't listed, and isn't counted as selling.
Q2 2026
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−9.3%)
Q1 2026
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−40.4%)
Q3 2025
1 superinvestor holding at quarter end
- Added
- Southeastern Asset Management (Longleaf) (+50.1%)
Q2 2025
1 superinvestor holding at quarter end
- Added
- Southeastern Asset Management (Longleaf) (+14.1%)
Q1 2025
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−3.9%)
Q4 2024
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−7.2%)
Q3 2024
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−3.2%)
Q2 2024
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−13.3%)
Q1 2024
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−23.8%)
Q4 2023
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−1.5%)
Q3 2023
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−22.0%)
Q2 2023
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−21.1%)
Q1 2023
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−3.5%)
Q4 2022
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−50.7%)
Q3 2022
1 superinvestor holding at quarter end
- Reduced
- Southeastern Asset Management (Longleaf) (−10.4%)
Q2 2022
1 superinvestor holding at quarter end
- Added
- Southeastern Asset Management (Longleaf) (+0.1%)
Q1 2022
1 superinvestor holding at quarter end
- Added
- Southeastern Asset Management (Longleaf) (+143.2%)
Q4 2021
1 superinvestor holding at quarter end