White Mountains Insurance Group (WTM)
Builds and supports insurance, reinsurance, and financial-services businesses.
$2,048.95
vs last close−4.69 (−0.23%)
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13F · 13D/G · Form 4
| Institutions | 93.28% | 2.23M shares | |
|---|---|---|---|
| 359 holders · as of Jun 30, 2026 | |||
| Insiders | 2.69% | 64.2K shares | |
| 17 holders · as of Aug 31, 2026 | |||
| Other | 4.03% | 96.2K shares | |
| remainder | |||
2.39M company shares as of Sep 23, 2026 · institutions as of Jun 30, 2026 · holders as of their latest filing
13F, as of Jun 30, 2026
359 holders · 2.23M shares · 41 new positions · 137 increased · 146 reduced · 50 closed
| Holder | Shares | % outstanding | Chg q/q | Filed |
|---|---|---|---|---|
| Dimensional Fund Advisors LP | 159.0K | 6.66% | +2.3K | Aug 11, 2026 |
| Neuberger Berman Group LLC | 119.1K | 4.99% | −5.6K | Aug 13, 2026 |
| BlackRock, Inc. | 117.9K | 4.94% | +4.5K | Aug 7, 2026 |
| River Road Asset Management, LLC | 115.9K | 4.86% | −4.6K | Jul 17, 2026 |
| Vanguard Portfolio Management LLC | 112.0K | 4.69% | −3.6K | Aug 13, 2026 |
| Vanguard Capital Management LLC | 107.5K | 4.50% | −1.7K | Aug 13, 2026 |
| Fuller & Thaler Asset Management, Inc. | 101.9K | 4.27% | −2.7K | Aug 12, 2026 |
| Cooke & Bieler LP | 85.1K | 3.57% | −19.7K | Jul 30, 2026 |
13D/G · 5% or more, as filed
| Holder | % of class | Shares | Form | Filed |
|---|---|---|---|---|
| Vanguard Capital Management | 5.18% | 128.0K | 13G | Apr 30, 2026 |
Form 4
Latest trades
| Date | Insider | Type | Shares | Avg price | Owned after |
|---|---|---|---|---|---|
| Dec 19, 2025 | George Manning Rountreedirector, officer: Chief Executive Officer | Sale | 5,000 | $2,050.00 | 13,809 |
| Dec 19, 2025 | Reid Tarlton Campbelldirector | Sale · 2 lots | 10,000 | $2,050.00 | 10,440 |
| Dec 16, 2025 | Philip A. Gelstondirector | Sale | 165 | $2,048.51 | 1,568 |
House and Senate disclosures
| Member | Type | Amount | Owner | Traded | Disclosed |
|---|---|---|---|---|---|
| Rep. Michael McCaul · TX10 | Sale | $1,001 – $15,000 | Spouse | Jun 18, 2026 | Jul 13, 2026 |