WTM · White Mountains Insurance Group Ltd · Shareholders & Ownership

$2,258.49 -35.68 (-1.56%)

Russell 1000 member Rebalance outlook locked

Market Cap

$5.48B

2.39M

Volume · Nov 6 8325 Avg daily vol (3M) 21.77K

Every disclosed holder of WTM in one list: 13F institutions, Schedule 13D and 13G filers, insiders (Forms 3, 4 and 5) and registered funds, each from its own latest filing. Holders nest by CIK and SEC reporting links, never by name, and each is summed once.

How the holder list picks a filing →

Who Owns WTM

13F quarter Sep 30, 2026, combined view: filers that have not filed yet carry their Jun 30, 2026 positions

Holder group	Holders	Shares	% Out	Summed
Institutional (13F)	372	2,213,658	92.75%	Yes
Insiders (Forms 3, 4, 5)	17	77,859	3.26%	Yes
13D/G-only blocks	0	0	0.00%	Yes
Remaining	—	95,306	3.99%	Rest
Registered funds (N-PORT, not summed)	92	409,416	17.15%	No

Shares outstanding: 2,386,823, the issuer's latest cover-page count restated onto today's split basis.

13D/G-only counts each filer's latest 13D or 13G that no 13F report of the listing contains, that names no 13F filer and that no counted insider files. Funds are never summed: their shares sit inside their advisers' 13F reports.

Holders of WTM

One row per holder Every filing By ultimate parent

All 13F Funds Insiders 13D/G Non-US

#	Holder	Shares	% Out	Change	As of	Notes
1	DIMENSIONAL FUND ADVISORS LP 13F CIK 354204 · Registered investment adviser · Sep 30, 2026	160,597	6.73%	+1,643	Sep 30, 2026
1.1	Dimensional U.S. Targeted Value ETF Fund S000070901 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	17,371	0.73%	+97	Jul 31, 2026	Dimensional ETF Trust, not summed
1.2	Dimensional US Small Cap Value ETF Fund S000075151 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	12,998	0.54%	+559	Jul 31, 2026	Dimensional ETF Trust, not summed
1.3	Dimensional U.S. Small Cap ETF Fund S000070906 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	7,718	0.32%	+238	Jul 31, 2026	Dimensional ETF Trust, not summed
1.4	Dimensional U.S. Core Equity 2 ETF Fund S000070903 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	5,391	0.23%	0	Jul 31, 2026	Dimensional ETF Trust, not summed
1.5	Dimensional U.S. Marketwide Value ETF Fund S000075030 · Registered fund · Jul 31, 2026 Dimensional ETF Trust, not summed	1,979	0.08%	+16	Jul 31, 2026	Dimensional ETF Trust, not summed
2	NEUBERGER BERMAN GROUP LLC 13F CIK 1465109 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	119,141	4.99%	-5,574	Jun 30, 2026	carried, not yet filed for the newest quarter
3	BlackRock, Inc. 13F CIK 2012383 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	117,871	4.94%	+4,543	Jun 30, 2026	carried, not yet filed for the newest quarter
3.1	iShares Russell 1000 Value ETF Fund S000004345 · Registered fund · Jun 30, 2026 iShares Trust, not summed	5,395	0.23%	-285	Jun 30, 2026	iShares Trust, not summed
3.2	iShares U.S. Financials ETF Fund S000004323 · Registered fund · Jul 31, 2026 iShares Trust, not summed	1,683	0.07%	+312	Jul 31, 2026	iShares Trust, not summed
3.3	iShares Russell 1000 ETF Fund S000004347 · Registered fund · Jun 30, 2026 iShares Trust, not summed	1,668	0.07%	-39	Jun 30, 2026	iShares Trust, not summed
3.4	iShares U.S. Insurance ETF Fund S000009421 · Registered fund · Jun 30, 2026 iShares Trust, not summed	1,169	0.05%	+80	Jun 30, 2026	iShares Trust, not summed
3.5	iShares Focused Value Factor ETF Fund S000064965 · Registered fund · Jun 30, 2025 iShares Trust, not summed	400	0.02%	+45	Jun 30, 2025	iShares Trust, not summed
4	River Road Asset Management, LLC 13F CIK 1341401 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	115,880	4.86%	-4,639	Jun 30, 2026	carried, not yet filed for the newest quarter
5	VANGUARD PORTFOLIO MANAGEMENT LLC 13F CIK 2100121 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	111,969	4.69%	-3,584	Jun 30, 2026	carried, not yet filed for the newest quarter
6	VANGUARD CAPITAL MANAGEMENT LLC 13F CIK 2100119 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	107,479	4.50%	-1,678	Jun 30, 2026	carried, not yet filed for the newest quarter
7	FULLER & THALER ASSET MANAGEMENT, INC. 13F CIK 1082327 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	101,892	4.27%	-2,669	Jun 30, 2026	carried, not yet filed for the newest quarter
8	COOKE & BIELER LP 13F CIK 24386 · Registered investment adviser · Sep 30, 2026	87,203	3.65%	+2,083	Sep 30, 2026
9	Wallace Capital Management Inc. 13F CIK 1459754 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	80,067	3.35%	+1,272	Jun 30, 2026	carried, not yet filed for the newest quarter
10	VANGUARD TOTAL STOCK MARKET INDEX FUND Fund S000002848 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	74,657	3.13%	-2,233	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
11	FIDUCIARY MANAGEMENT INC /WI/ 13F CIK 764532 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	66,550	2.79%	-18,516	Jun 30, 2026	carried, not yet filed for the newest quarter
12	GENDELL JEFFREY L 13F CIK 1056581 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	59,243	2.48%	+21,429	Jun 30, 2026	carried, not yet filed for the newest quarter
13	Boston Partners 13F CIK 1386060 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	55,569	2.33%	-1,890	Jun 30, 2026	carried, not yet filed for the newest quarter
14	LONDON CO OF VIRGINIA 13F CIK 1259887 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	54,025	2.26%	-3,106	Jun 30, 2026	carried, not yet filed for the newest quarter
15	VANGUARD SMALL-CAP INDEX FUND Fund S000002845 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	53,965	2.26%	-1,955	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
16	STATE STREET CORP 13F CIK 93751 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	50,257	2.11%	+1,099	Jun 30, 2026	carried, not yet filed for the newest quarter
17	GEODE CAPITAL MANAGEMENT, LLC 13F CIK 1214717 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	49,412	2.07%	+7,293	Jun 30, 2026	carried, not yet filed for the newest quarter
18	MORGAN STANLEY 13F CIK 895421 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	46,866	1.96%	-12,429	Jun 30, 2026	carried, not yet filed for the newest quarter
19	REINHART PARTNERS, LLC. 13F CIK 1080298 · Registered investment adviser · Sep 30, 2026	43,959	1.84%	-521	Sep 30, 2026
20	VANGUARD SELECTED VALUE FUND Fund S000004409 · Registered fund · Jul 31, 2026 VANGUARD WHITEHALL FUNDS, not summed	34,926	1.46%	-4,312	Jul 31, 2026	VANGUARD WHITEHALL FUNDS, not summed
21	T. Rowe Price Investment Management, Inc. 13F CIK 1897612 · Investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	34,237	1.43%	-7,276	Jun 30, 2026	carried, not yet filed for the newest quarter
22	VANGUARD SMALL-CAP VALUE INDEX FUND Fund S000002847 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	34,181	1.43%	-1,432	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
23	LORD, ABBETT & CO. LLC 13F CIK 728100 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	32,829	1.38%	-281	Jun 30, 2026	carried, not yet filed for the newest quarter
24	Avantis U.S. Small Cap Value ETF Fund S000066459 · Registered fund · Aug 31, 2026 American Century ETF Trust, not summed	32,024	1.34%	+7,433	Aug 31, 2026	American Century ETF Trust, not summed
25	AMERICAN CENTURY COMPANIES INC 13F CIK 748054 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	31,108	1.30%	+22,800	Jun 30, 2026	carried, not yet filed for the newest quarter
26	VANGUARD EXTENDED MARKET INDEX FUND Fund S000002841 · Registered fund · Jun 30, 2026 VANGUARD INDEX FUNDS, not summed	28,016	1.17%	+707	Jun 30, 2026	VANGUARD INDEX FUNDS, not summed
27	NORGES BANK 13F CIK 1374170 · Non-US institution · Jun 30, 2026 carried, not yet filed for the newest quarter	27,956	1.17%	—	Jun 30, 2026	carried, not yet filed for the newest quarter
28	Cannell & Spears LLC 13F CIK 1426319 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	27,577	1.16%	-450	Jun 30, 2026	carried, not yet filed for the newest quarter
29	BANK OF AMERICA CORP /DE/ 13F CIK 70858 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	25,028	1.05%	-3,330	Jun 30, 2026	carried, not yet filed for the newest quarter
30	CHARLES SCHWAB INVESTMENT MANAGEMENT INC 13F CIK 884546 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	23,505	0.98%	-736	Jun 30, 2026	carried, not yet filed for the newest quarter
31	Mraz, Amerine & Associates, Inc. 13F CIK 1542324 · Registered investment adviser · Sep 30, 2026	22,147	0.93%	-71	Sep 30, 2026
32	SEELIG ROBERT LAWRENCE Insider CIK 1188198 · Mar 19, 2026 EVP & General Counsel, issuer-wide	20,944	0.88%	-50	Mar 19, 2026	EVP & General Counsel, issuer-wide
33	Allspring Global Investments Holdings, LLC 13F CIK 1890906 · Holding company · Sep 30, 2026	20,229	0.85%	+2,113	Sep 30, 2026
34	Rountree George Manning Insider CIK 1457475 · Dec 19, 2025 Director, Chief Executive Officer, issuer-wide	19,356	0.81%	-4,998	Dec 19, 2025	Director, Chief Executive Officer, issuer-wide
35	Gotham Asset Management, LLC 13F CIK 1510387 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	17,940	0.75%	+8,893	Jun 30, 2026	carried, not yet filed for the newest quarter
36	BROWN ADVISORY INC 13F CIK 1345929 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	17,722	0.74%	-122	Jun 30, 2026	carried, not yet filed for the newest quarter
37	JANE STREET GROUP, LLC 13F CIK 1595888 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	17,226	0.72%	+3,418	Jun 30, 2026	carried, not yet filed for the newest quarter
38	SOUTHEASTERN ASSET MANAGEMENT INC/TN/ 13F CIK 807985 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	17,104	0.72%	-1,760	Jun 30, 2026	carried, not yet filed for the newest quarter
38.1	Longleaf Partners Small Cap Fund Fund S000009312 · Registered fund · Jun 30, 2026 Longleaf Partners Funds Trust, not summed	15,233	0.64%	0	Jun 30, 2026	Longleaf Partners Funds Trust, not summed
39	UBS Group AG 13F CIK 1610520 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	16,198	0.68%	+5,757	Jun 30, 2026	carried, not yet filed for the newest quarter
40	VANGUARD FIDUCIARY TRUST CO 13F CIK 933478 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	15,319	0.64%	+133	Jun 30, 2026	carried, not yet filed for the newest quarter
41	RAYMOND JAMES FINANCIAL INC 13F CIK 720005 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	14,833	0.62%	-9,118	Jun 30, 2026	carried, not yet filed for the newest quarter
42	NORTHERN TRUST CORP 13F CIK 73124 · Bank · Jun 30, 2026 carried, not yet filed for the newest quarter	14,571	0.61%	-924	Jun 30, 2026	carried, not yet filed for the newest quarter
43	WELLINGTON MANAGEMENT GROUP LLP 13F CIK 902219 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	14,532	0.61%	-352	Jun 30, 2026	carried, not yet filed for the newest quarter
44	ENVESTNET ASSET MANAGEMENT INC 13F CIK 1407543 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	13,838	0.58%	-1,725	Jun 30, 2026	carried, not yet filed for the newest quarter
45	Quantinno Capital Management LP 13F CIK 1759654 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	12,624	0.53%	+2,840	Jun 30, 2026	carried, not yet filed for the newest quarter
46	ELKHORN PARTNERS LIMITED PARTNERSHIP 13F CIK 928400 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	12,320	0.52%	-380	Jun 30, 2026	carried, not yet filed for the newest quarter
47	HORIZON KINETICS ASSET MANAGEMENT LLC 13F CIK 1056823 · Registered investment adviser · Jun 30, 2026 carried, not yet filed for the newest quarter	12,206	0.51%	-906	Jun 30, 2026	carried, not yet filed for the newest quarter
48	GOLDMAN SACHS GROUP INC 13F CIK 886982 · Holding company · Jun 30, 2026 carried, not yet filed for the newest quarter	12,151	0.51%	-3,632	Jun 30, 2026	carried, not yet filed for the newest quarter
49	BOUSSARD & GAVAUDAN GESTION SAS 13F CIK 1569001 · Unknown · Jun 30, 2026 carried, not yet filed for the newest quarter	11,679	0.49%	—	Jun 30, 2026	carried, not yet filed for the newest quarter
50	VANGUARD GLOBAL MINIMUM VOLATILITY FUND Fund S000043242 · Registered fund · Jul 31, 2026 VANGUARD WHITEHALL FUNDS, not summed	11,312	0.47%	0	Jul 31, 2026	VANGUARD WHITEHALL FUNDS, not summed

7 more nested rows are not shown here; Every filing lists them all.

Shares are restated onto today's split basis. Change compares each row with the same holder's previous filing in the same source; a dash means there is none to compare. Nested 13D/G, insider and fund rows are not summed, since a 13F report already holds them.

Showing 1–50 of 444 holders

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Key facts CIK 776867 CUSIP G9618E107 13F (30d) 173 filings 145 filers Visit website Investor relations