WHITE MOUNTAINS INSURANCE GROUP LTD (WTM)
NYSE · Insurance · Fire, Marine & Casualty Insurance
- Price
- $2,032.01
- Day
- -1.05%
- Market cap
- $4.85B
- P/E
- 4.1
Close 2026-09-23.
The company
Overview The Ark/WM Outrigger segment consists of Ark and WM Outrigger Re. On January 1, 2021, White Mountains acquired a controlling ownership interest in Ark (the “Ark Transaction”). Ark is a specialty property and casualty insurance and reinsurance company that offers a wide range of niche insurance and reinsurance products, including property, specialty, marine & energy, casualty and accident & health. During the fourth quarter of 2022, Ark sponsored the formation of Outrigger Re Ltd., a Bermuda company registered as a special purpose insurer and segregated accounts company, to provide collateralized reinsurance protection on Ark’s Bermuda global property catastrophe excess of loss portfolio written in the 2023 underwriting year. Ark renewed its quota share reinsurance agreement with Outrigger Re Ltd. for the 2024, 2025 and 2026 underwriting years. White Mountains consolidates its segregated account of Outrigger Re Ltd., WM Outrigger Re, in its financial statements. White Mountains’s capital commitment to WM Outrigger Re was $150 million for the 2025 underwriting year, $130 million for the 2024 underwriting year and $205 million for the 2023 underwriting year. WM Outrigger Re is not participating in the 2026 underwriting year; however, WM Outrigger Re remains exposed to losses that occur prior to the expiration of the 2025 underwriting year on June 30, 2026.
From Item 1: Overview.
Institutional holders
Largest positions reported on Form 13F for the quarter ended 2026-06-30, by value.
- DIMENSIONAL FUND ADVISORS LP — $315.3M
- NEUBERGER BERMAN GROUP LLC — $245.07M
- River Road Asset Management, LLC — $240.26M
- VANGUARD PORTFOLIO MANAGEMENT LLC — $232.16M
- VANGUARD CAPITAL MANAGEMENT LLC — $222.85M
- FULLER & THALER ASSET MANAGEMENT, INC. — $211.26M
- COOKE & BIELER LP — $176.49M
- Wallace Capital Management Inc. — $166.01M
Insider trades
Open-market buys and sales filed on Form 4, newest first. Grants, option exercises and tax withholding are left out.
- CAMPBELL REID TARLTON (Director) sold 5,000 shares at $2,050.00 on 2025-12-19
- CAMPBELL REID TARLTON (Director) sold 5,000 shares on 2025-12-19
- Rountree George Manning (Chief Executive Officer) sold 5,000 shares at $2,050.00 on 2025-12-19
- Gelston Philip A (Director) sold 165 shares at $2,048.51 on 2025-12-16
Recent filings
- 4 — 2026-08-31
- 3 — 2026-08-27
- 4 — 2026-08-27
- 8-K — 2026-08-27
- 10-Q — 2026-08-06
- 8-K — 2026-08-06
- 8-K — 2026-06-05
- 4 — 2026-05-22
- 4 — 2026-05-22
- 4 — 2026-05-22