White Mountains Insurance Group, Ltd. (WTM) Institutional Ownership & Insider Trading

356 institutions reported holding White Mountains Insurance Group, Ltd. shares in 13F filings for the quarter ended 2026-06-30, according to EquiReason's reading of their SEC filings. 2 insider trades on Form 4 since 2025-10-01.

Source: SEC EDGAR filings · figures as of 2026-06-30 · read by EquiReason

WTMWhite Mountains Insurance Group, Ltd.Follow WTM — free

Insurance - Property & Casualty · Financials

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Market cap: 5.3B
P/E TTM: 4.9
Dividend yield: 0.0%
52-week: —
Next earnings: 9 Nov, in 16 days

Institutions · all 13F filers

quarter to 30 Jun 2026 · filers in both quarters

356 institutions held 92.3% of the shares. Across filers that reported both quarters, shares held changed -1.5%.

Largest moves, shares (millions)

Institutional flow by quarter

net shares added or trimmed, millions · filers in both quarters

Quarter	Holders	Shares held, M	Change	Increased	New	Decreased	Closed
Jun 26	356	2	-1.5%	85	27	128	37
Mar 26	364	2	-6.0%	106	34	101	22
Dec 25	351	2	-0.0%	94	42	116	29
Sep 25	332	2	+1.8%	89	35	92	18
Jun 25	322	2	+0.8%	93	24	95	18
Mar 25	317	2	+1.4%	91	21	91	22
Dec 24	320	2	+1.1%	98	26	66	11
Sep 24	301	2	-10.5%	93	19	70	19

White Mountains Insurance Group, Ltd. — questions

Who owns White Mountains Insurance Group, Ltd. stock?: 356 institutions reported White Mountains Insurance Group, Ltd. shares in 13F filings for the quarter ended 2026-06-30. The largest: DIMENSIONAL FUND ADVISORS LP (6.7%), NEUBERGER BERMAN GROUP LLC (5.0%), BlackRock, Inc. (4.9%).
Are White Mountains Insurance Group, Ltd. insiders buying or selling?: 2 insider trades on Form 4 since 2025-10-01; the full list, with dates, people and plan status, is on this page.

Every figure on this page comes from White Mountains Insurance Group, Ltd.'s own SEC filings — see them on SEC EDGAR. Price data is licensed and shown only inside the product.

How these figures are read: methodology · EquiReason.

Important information. Figures on this page are taken from filings submitted to the U.S. Securities and Exchange Commission (SEC) and processed automatically by EquiReason. They may contain errors, omissions or delays, and EquiReason makes no representation or warranty as to their accuracy, completeness or timeliness. Always verify figures against the original filing on SEC EDGAR before relying on them.

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