White Mountains Insurance Group Ltd. (WTM)
FIRE, MARINE & CASUALTY INSURANCE
White Mountains Insurance Group Ltd. (WTM) is listed on the New York Stock Exchange, where it has traded since October 23, 1985.
- Listed On
- the New York Stock Exchange
- Listed Since
- October 23, 1985
- Employees
- 1,648
- Market Cap
- $5.3B
About White Mountains Insurance Group Ltd.
White Mountains Insurance Group Ltd is engaged in the business of making opportunistic and value-oriented acquisitions of businesses and assets in the insurance, financial services, and related sectors, operating these businesses and assets through its subsidiaries and, if and when attractive exit valuations become available, disposing of these businesses and assets. The company conducts its business in five areas: property and casualty insurance and reinsurance, municipal bond reinsurance, capital solutions for asset and wealth management firms, property and casualty insurance distribution, and other operations. The company has four reportable segments: Ark/WM Outrigger, HG Global, Kudu and Distinguished.
Institutional ownership
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. The largest reported holder was Vanguard, with 238,978 shares worth $495.5 million. Of the 5 largest holders listed below, 2 added shares and 3 reduced their positions during the quarter.
| Institution | Shares | Value | Quarter change |
|---|---|---|---|
| Vanguard | 238,978 | $495M | Reduced 2.12% |
| Dimensional Fund Advisors | 158,954 | $330M | Added 1.49% |
| Neuberger Berman Group | 119,141 | $247M | Reduced 4.47% |
| BlackRock | 117,871 | $244M | Added 4.01% |
| River Road Asset Management | 115,880 | $240M | Reduced 3.85% |
Form 13F is a quarterly report that institutional investment managers with at least $100 million in qualifying securities file with the SEC. It lists long positions as of the last day of the quarter and is due within 45 days of quarter end, so these holdings describe that date rather than today.
Frequently asked questions
What is WTM?
White Mountains Insurance Group Ltd. (WTM) is listed on the New York Stock Exchange, where it has traded since October 23, 1985.
Who are the largest institutional holders of WTM?
In 13F filings for the quarter ended June 30, 2026, the largest reported holders of WTM were Vanguard, Dimensional Fund Advisors and Neuberger Berman Group.
How many institutions own WTM?
343 institutions reported a position in WTM for the quarter ended June 30, 2026, worth $4.6 billion in total.
Did institutions buy or sell WTM last quarter?
Of the 5 largest reported holders, 2 added shares and 3 reduced their positions during the quarter. Every reported holder and its change is on the SentiSense ownership page for WTM.
Every reported institutional holder, plus insider and congressional trades in WTM, on SentiSense.