WM
White Mountains Insurance Group LTD
Concentrated strategyMomentum followerQuality / disciplined sizing
Total reported value
$313.4M
Reporting period: 2026-03-31 · Number of holdings: 2
WHITE MOUNTAINS INSURANCE GROUP LTD disclosed 2 holdings in its latest 13F filing for the period ending 2026-03-31, with total reported value of $313.4M and a quarterly turnover rate of 63.2%.
Personality snowflake
- Concentration
- 100
- Portfolio Stability
- 63.2
- Momentum/Contrarian
- 100
- Sector conviction
- 0
- Diversification
- 4
- Sizing Uniformity
- 99.15
Recent moves
Add SPY
+403.3% $116.6M
Trim MAX
0.0% -$65.2M
Holdings Map
New buyAddUnchangedTrim
Top 10 holdings by weight
Full holdings list this quarter
| # | Ticker | Issuer | Asset Subclass | Weight | Weight Change | Shares Change | 4Q Trend |
|---|---|---|---|---|---|---|---|
| 1 | MAX | Mediaalpha Inc-class A | Stock-Other | 52.99% | -35.29% | — | |
| 2 | SPY | Ss Spdr S&p 500 ETF Trust-us | ETF-Large Cap & Growth | 47.01% | +35.29% | +403.33% |
Reported value over time
Sector allocation
Not enough sector-mapped data yet
Sector allocation over time
Quarterly history
| Period | Holdings | Total value | Stability | Top holdings |
|---|---|---|---|---|
| 2026-03-31 | 2 | $313.4M | 63 | |
| 2025-12-31 | 2 | $261.9M | 25 | |
| 2025-09-30 | 1 | $203.2M | 80 | |
| 2025-06-30 | 1 | $195.5M | 0 | |
| 2025-03-31 | 2 | $285.9M | 100 | |
| 2024-12-31 | 2 | $426.2M | 0 | |
| 2024-09-30 | 2 | $543.2M | 0 | |
| 2024-06-30 | 2 | $443.7M | 0 | |
| 2024-03-31 | 2 | $617.2M | 0 | |
| 2023-12-31 | 2 | $392.6M | 0 | |
| 2023-09-30 | 2 | $440.9M | 0 | |
| 2023-06-30 | 2 | $508.2M | 0 | |
| 2023-03-31 | 2 | $611.1M | 0 | |
| 2022-12-31 | 2 | $502.4M | 0 | |
| 2022-09-30 | 2 | $194.7M | 0 | |
| 2022-06-30 | 1 | $166.9M | 0 | |
| 2022-03-31 | 1 | $280.4M | 0 | |
| 2021-12-31 | 1 | $261.6M | 0 | |
| 2021-09-30 | 1 | $316.4M | 0 | |
| 2021-06-30 | 1 | $713.2M | 100 | |
| 2021-03-31 | 1 | $600.2M | 29 | |
| 2020-12-31 | 1 | $802.2M | 100 | |
| 2015-12-31 | 1 | $653.3M | 0 | 187151Q |
| 2015-09-30 | 1 | $650.6M | 27 | 187151Q |
| 2015-06-30 | 1 | $497.0M | 6 | 187151Q |
| 2015-03-31 | 1 | $470.3M | 2 | 187151Q |
| 2014-12-31 | 1 | $462.1M | 1 | 187151Q |
| 2014-09-30 | 1 | $467.7M | 3 | 187151Q |
| 2014-06-30 | 1 | $455.9M | 14 | 187151Q |
| 2014-03-31 | 2 | $397.9M | 4 | 187151Q2SIEGY |
| 2013-12-31 | 2 | $380.7M | 6 | 187151Q2SIEGY |
| 2013-09-30 | 2 | $357.7M | 11 | 187151Q2SIEGY |
| 2013-06-30 | 2 | $321.0M | — | 187151Q2SIEGY |
Holding changes this quarter
White Mountains Insurance Group LTD's most significant position changes for 2026-03-31: Add: Ss Spdr S&p 500 ETF Trust-us (SPY) — shares +403.33%.
| # | Ticker | Issuer | Weight Change | Shares Change | Action |
|---|---|---|---|---|---|
| 1 | SPY | Ss Spdr S&p 500 ETF Trust-us | +35.3% | +403.33% | Add |
| 2 | MAX | Mediaalpha Inc-class A | -35.3% | — | Unchanged |
FAQ
What is White Mountains Insurance Group LTD and what type of investor is it?
White Mountains Insurance Group LTD is a investment manager that files SEC Form 13F quarterly, disclosing its U.S. public equity holdings to regulators. As of the most recent reporting period (2026-03-31), the firm manages a tracked equity portfolio valued at approximately $313.4M, spread across 2 disclosed positions.
What are White Mountains Insurance Group LTD's largest equity positions?
Based on the latest 13F filing, White Mountains Insurance Group LTD's top holdings by market value are:
1. Mediaalpha Inc-class A (MAX) — $166.1M (53.0%)
2. Ss Spdr S&p 500 ETF Trust-us (SPY) — $147.3M (47.0%)
What changes did White Mountains Insurance Group LTD make in its most recent portfolio filing?
In the latest quarter, White Mountains Insurance Group LTD was primarily adding exposure — initiating 0 new positions and adding to 1 existing holdings. The largest of these moves: Add: Ss Spdr S&p 500 ETF Trust-us (SPY) — shares +403.33%
What sectors does White Mountains Insurance Group LTD focus on?
Sector breakdown data is not yet available for White Mountains Insurance Group LTD. Check back after the next 13F processing cycle.