White Mountains Insurance Group Ltd. (WTM) Ownership & Trading Activity
Institutional holders, insider transactions, and congressional trades for WTM. 13F holdings as of 2026-06-30.
In 13F filings for the quarter ended June 30, 2026, 343 institutions reported holding WTM, with 2.2 million shares worth $4.6 billion in aggregate.
Top Institutional Holders
| Institution | Shares | Value | Change |
|---|---|---|---|
| Vanguard | 238,978 | $495M | DECREASED |
| Dimensional Fund Advisors | 158,954 | $330M | INCREASED |
| Neuberger Berman Group | 119,141 | $247M | DECREASED |
| BlackRock | 117,871 | $244M | INCREASED |
| River Road Asset Management | 115,880 | $240M | DECREASED |
Full institutional holdings, insider history, and congressional trades for White Mountains Insurance Group Ltd. on SentiSense.