Institutional Manager · CIK 0000776867
WHITE MOUNTAINS INSURANCE GROUP LTD
Hanover, NH · File #028-01681
Latest AUM
$261.9M
Positions
2
Top-10 Concentration
100.0%
Filings
9
Portfolio Value Over Time
2024-03
2024-06
2024-09
2024-12
2025-03
2025-06
2025-09
2025-12
Biggest QoQ Changes
Ranked by conviction flow (share change × current price) so mark-to-market moves don't dominate. Price effect column shows how much of the $ change was just the stock moving.
| Action | Issuer | Ticker / CUSIP | Δ Shares | Flow ($) | Price Effect |
|---|---|---|---|---|---|
| NEW | SPDR S&P 500 ETF TR | SPY | +45,000 | +$30.7M | $0 |
| REDUCE | MEDIAALPHA INC | MAX | 0 | $0 | +$28.0M |
Sector Allocation
Filing History
- 13F HOLDINGS REPORTQ/E Dec 20252 pos · $261.9M
- 13F HOLDINGS REPORTQ/E Sep 20251 pos · $203.2M
- 13F HOLDINGS REPORTQ/E Jun 20251 pos · $195.5M
- 13F HOLDINGS REPORTQ/E Mar 20252 pos · $285.9M
- 13F HOLDINGS REPORTQ/E Dec 20242 pos · $426.2M
- 13F HOLDINGS REPORTQ/E Sep 20242 pos · $543.2M
- 13F HOLDINGS REPORTQ/E Jun 20242 pos · $443.7M
- 13F HOLDINGS REPORTQ/E Mar 20242 pos · $617.2M
- 13F HOLDINGS REPORTQ/E Dec 20232 pos · $440.9M
Top 2 Holdings — Dec 2025
| # | Issuer | Ticker | Shares | Value | % of Portfolio |
|---|---|---|---|---|---|
| 1 | MEDIAALPHA INC | MAX | 17,856,614 | $231.2M | 88.28% |
| 2 | SPDR S&P 500 ETF TR | SPY | 45,000 | $30.7M | 11.72% |