White Mountains Insurance WTM Institutional Ownership

NYSE WTM

$2,104.75 +5.79 (+0.28%)

At close: Sep 2, 2026 · 4:04 PM EDT

Institutions by Trading Activity

353 Institutions

Increased 137 38.8%

Unchanged 75 21.2%

Reduced 141 39.9%

Ownership Statistics

13F · as of 30 Jun, 2026

Institutional Ownership

90.02%

▼-0.66 pp QoQ

Shares Held by Institutions

2.20Mn

of 2.44Mn outstanding

▲+3.07% QoQ

Shares Outstanding

2.44Mn

243.41K held outside 13F filers

Institutional Investors

353

filed 13F for Jun 2026

▼-11 vs prior quarter

Net Shares Added (QoQ)

+65.49K

accumulated since last quarter

Value of Holdings

$4.61Bn

reported market value

Shares Owned by Institutions

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Shares Purchased/Sold by Institutions

Accumulated Distributed

Latest quarter —

Net over range —

Accumulating quarters —

Ownership Summary

Quarter ending 30 Jun, 2026

White Mountains Insurance Group Ltd (NYSE:WTM) is held by 353 institutional investors per 13F filings through June 2026.

They owned 90.0% of outstanding stock in June 2026, down from 90.7% the prior quarter.
They increased total shares held in WTM by 3.07% quarter over quarter, and investors in White Mountains Insurance increased 9.97% from a year ago.
During the quarter, 137 of these 353 funds increased positions in WTM, 141 reduced exposure, and 75 held steady.
The aggregate institutional position in White Mountains Insurance amounted to 2.2Mn shares as of June 2026, up by 65.49K shares quarter on quarter, and down 140.19K shares year over year.
As of June 30, 2026, DIMENSIONAL FUND ADVISORS LP held the largest stake in White Mountains Insurance with 158.95K shares, accounting for 6.52% of total shares outstanding.
The biggest buyers of White Mountains Insurance for the quarter ending June 2026 included NORGES BANK (27.96K), Sixth Street Partners Management Company, L.P. (23.5K), AMERICAN CENTURY COMPANIES INC (22.8K), GENDELL JEFFREY L (21.43K), BOUSSARD & GAVAUDAN GESTION SAS (11.68K).
The largest sales of WTM for the quarter ending June 2026 came from COOKE & BIELER LP (19.74K), FIDUCIARY MANAGEMENT INC /WI/ (18.52K), Morgan Stanley (12.43K), Raymond James Financial Inc (9.12K), UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC (7.76K).
White Mountains Insurance's 10 largest shareholders as of June 2026 include DIMENSIONAL FUND ADVISORS LP (158.95K), Neuberger Berman Group LLC (119.14K), BlackRock, Inc. (117.85K), River Road Asset Management, LLC (115.88K), VANGUARD PORTFOLIO MANAGEMENT LLC (111.97K), VANGUARD CAPITAL MANAGEMENT LLC (107.48K), FULLER & THALER ASSET MANAGEMENT, INC. (101.89K), COOKE & BIELER LP (85.12K), Wallace Capital Management Inc. (80.07K), FIDUCIARY MANAGEMENT INC /WI/ (66.55K) per Business Quant data.

Form 13F Holdings

353 Institutional Holders

Report period 30 Jun, 2026

Total shares held 2.20Mn

Of outstanding 90.02%

#	Institution	CIK	Shares Held	% of Outstanding	Change (QoQ)	Change (%)	Value (USD)
1	DIMENSIONAL FUND ADVISORS LP	0000354204	158,954	6.52%	▲2,336	+1.49%	$329.58Mn
2	Neuberger Berman Group LLC	0001465109	119,141	4.88%	▼5,574	-4.47%	$247.03Mn
3	BlackRock, Inc.	0002012383	117,849	4.83%	▲4,521	+3.99%	$244.35Mn
4	River Road Asset Management, LLC	0001341401	115,880	4.75%	▼4,639	-3.85%	$240.26Mn
5	VANGUARD PORTFOLIO MANAGEMENT LLC	0002100121	111,969	4.59%	▼3,584	-3.10%	$232.16Mn
6	VANGUARD CAPITAL MANAGEMENT LLC	0002100119	107,479	4.41%	▼1,678	-1.54%	$222.85Mn
7	FULLER & THALER ASSET MANAGEMENT, INC.	0001082327	101,892	4.18%	▼2,669	-2.55%	$211.26Mn
8	COOKE & BIELER LP	0000024386	85,120	3.49%	▼19,737	-18.82%	$176.49Mn
9	Wallace Capital Management Inc.	0001459754	80,067	3.28%	▲1,272	+1.61%	$166.01Mn
10	FIDUCIARY MANAGEMENT INC /WI/	0000764532	66,550	2.73%	▼18,516	-21.77%	$137.98Mn
11	GENDELL JEFFREY L	0001056581	59,243	2.43%	▲21,429	+56.67%	$122.83Mn
12	Boston Partners	0001386060	55,569	2.28%	▼1,890	-3.29%	$115.28Mn
13	LONDON CO OF VIRGINIA	0001259887	54,025	2.21%	▼3,106	-5.44%	$112.08Mn
14	State Street Corp	0000093751	50,257	2.06%	▲1,099	+2.24%	$104.20Mn
15	GEODE CAPITAL MANAGEMENT, LLC	0001214717	49,412	2.03%	▲7,293	+17.32%	$102.47Mn
16	Morgan Stanley	0000895421	46,866	1.92%	▼12,429	-20.96%	$97.18Mn
17	REINHART PARTNERS, LLC.	0001080298	44,480	1.82%	▲7,106	+19.01%	$92.27Mn
18	T. Rowe Price Investment Management, Inc.	0001897612	34,237	1.40%	▼7,276	-17.53%	$70.99K
19	LORD, ABBETT & CO. LLC	0000728100	32,829	1.35%	▼281	-0.85%	$68.07K
20	AMERICAN CENTURY COMPANIES INC	0000748054	31,108	1.28%	▲22,800	+274.43%	$64.50Mn

Showing 1 to 20 of 353 holders