WHITE MOUNTAINS INSURANCE GROUP LTD (WTM) — Institutional Holders, Q2 2026

356 institutional investment managers reported a WTM position on SEC Form 13F-HR for the quarter ended June 30, 2026, with a combined reported value of $4.6B. Every filer is listed below, ranked by position value, 100 per page; this page shows ranks 1 to 100. Put and call option positions are excluded, and a firm filing several lots or share classes is shown once with its total.

← WTM stock profile

WTM in Q2 2026: what funds did

Funds that filed a 13F for both Q1 2026 and Q2 2026, by what they did with the common stock. Share counts are adjusted for any split between the two quarters; dollar figures are the change in shares at this quarter’s price.

New positions

Added to

Trimmed

145

Sold out

Biggest buyers

AMERICAN CENTURY COMPANIESAdded · +22,800 sh+$47.3M
GENDELL JEFFREY LAdded · +21,429 sh+$44.4M
Gotham Asset ManagementAdded · +8,893 sh+$18.4M
Qube Research & Technologies LtdAdded · +8,657 sh+$17.9M
FIRST ADVISORSAdded · +7,546 sh+$15.6M

Biggest sellers

COOKE & BIELERTrimmed · -19,737 sh-$40.9M
FIDUCIARY MANAGEMENTTrimmed · -18,516 sh-$38.4M
MORGAN STANLEYTrimmed · -12,429 sh-$25.8M
SUSQUEHANNA INTERNATIONAL GROUP, LLPSold out · -10,965 sh-$22.7M
Select Equity Group, L.P.Sold out · -10,560 sh-$21.9M

WTM 13F holders ranked 1–100 of 356

Institutional investors reporting a position in WHITE MOUNTAINS INSURANCE GROUP LTD on SEC Form 13F-HR for Q2 2026, ranked by reported value.
#	Institution	Shares	Value	% of portfolio	QoQShares vs Q1 2026
1	DIMENSIONAL FUND ADVISORS#1 · 158,954 sh	158,954	$329.6M	0.06%	+1.5%
2	Neuberger Berman Group#2 · 119,141 sh	119,141	$247.0M	0.16%	-4.5%
3	BlackRock#3 · 117,871 sh	117,871	$244.4M	<0.01%	+4.0%
4	River Road Asset Management#4 · 115,880 sh	115,880	$240.3M	2.67%	-3.8%
5	VANGUARD PORTFOLIO MANAGEMENT#5 · 111,969 sh	111,969	$232.2M	0.01%	-3.1%
6	VANGUARD CAPITAL MANAGEMENT#6 · 107,479 sh	107,479	$222.8M	<0.01%	-1.5%
7	FULLER & THALER ASSET MANAGEMENT#7 · 101,892 sh	101,892	$211.3M	0.58%	-2.6%
8	COOKE & BIELER#8 · 85,120 sh	85,120	$176.5M	—	-18.8%
9	Wallace Capital Management#9 · 80,067 sh	80,067	$166.0M	18.20%	+1.6%
10	FIDUCIARY MANAGEMENT#10 · 66,550 sh	66,550	$138.0M	1.96%	-21.8%
11	GENDELL JEFFREY L#11 · 59,243 sh	59,243	$122.8M	1.08%	+56.7%
12	Boston Partners#12 · 55,569 sh	55,569	$115.3M	0.10%	-3.3%
13	LONDON OF VIRGINIA#13 · 54,025 sh	54,025	$112.1M	0.64%	-5.4%
14	STATE STREET#14 · 50,257 sh	50,257	$104.2M	<0.01%	+2.2%
15	GEODE CAPITAL MANAGEMENT#15 · 49,412 sh	49,412	$102.5M	<0.01%	+17.3%
16	MORGAN STANLEY#16 · 46,866 sh	46,866	$97.2M	<0.01%	-21.0%
17	REINHART PARTNERS#17 · 44,480 sh	44,480	$92.3M	—	+19.0%
18	T. Rowe Price Investment Management#18 · 34,237 sh	34,237	$71.0M	0.05%	-17.5%
19	LORD, ABBETT#19 · 32,829 sh	32,829	$68.1M	0.19%	-0.8%
20	AMERICAN CENTURY COMPANIES#20 · 31,108 sh	31,108	$64.5M	0.03%	+274.4%
21	NORGES BANK#21 · 27,956 sh	27,956	$58.0M	<0.01%	—
22	Spears Abacus Advisors#22 · 27,577 sh	27,577	$57.2M	1.02%	-1.6%
23	BANK OF AMERICA#23 · 25,028 sh	25,028	$51.9M	<0.01%	-11.7%
24	CHARLES SCHWAB INVESTMENT MANAGEMENT#24 · 23,505 sh	23,505	$48.7M	<0.01%	-3.0%
25	Mraz, Amerine & Associates#25 · 22,218 sh	22,218	$46.1M	6.61%	+0.2%
26	Allspring Global Investments#26 · 18,116 sh	18,116	$37.4M	0.06%	-2.7%
27	Gotham Asset Management#27 · 17,940 sh	17,940	$37.2M	0.09%	+98.3%
28	BROWN ADVISORY#28 · 17,722 sh	17,722	$36.7M	0.06%	-0.7%
29	JANE STREET GROUP#29 · 17,226 sh	17,226	$35.7M	<0.01%	+24.8%
30	SOUTHEASTERN ASSET MANAGEMENT#30 · 17,104 sh	17,104	$35.5M	1.85%	-9.3%
31	UBS Group AG#31 · 16,198 sh	16,198	$33.6M	<0.01%	+55.1%
32	VANGUARD FIDUCIARY#32 · 15,319 sh	15,319	$31.8M	<0.01%	+0.9%
33	RAYMOND JAMES FINANCIAL#33 · 14,833 sh	14,833	$30.8M	<0.01%	-38.1%
34	NORTHERN#34 · 14,571 sh	14,571	$30.2M	<0.01%	-6.0%
35	WELLINGTON MANAGEMENT GROUP LLP#35 · 14,532 sh	14,532	$30.1M	<0.01%	-2.4%
36	ENVESTNET ASSET MANAGEMENT#36 · 13,838 sh	13,838	$28.7M	<0.01%	-11.1%
37	Quantinno Capital Management#37 · 12,624 sh	12,624	$26.2M	0.03%	+29.0%
38	ELKHORN PARTNERS LIMITED PARTNERSHIP#38 · 12,320 sh	12,320	$25.5M	21.89%	-3.0%
39	HORIZON KINETICS ASSET MANAGEMENT#39 · 12,206 sh	12,206	$25.3M	0.29%	-6.9%
40	GOLDMAN SACHS GROUP#40 · 12,151 sh	12,151	$25.2M	<0.01%	-23.0%
41	BOUSSARD & GAVAUDAN GESTION SAS#41 · 11,679 sh	11,679	$24.5M	1.23%	—
42	VICTORY CAPITAL MANAGEMENT#42 · 10,684 sh	10,684	$22.2M	0.01%	-4.1%
43	FIRST ADVISORS#43 · 10,604 sh	10,604	$22.0M	0.01%	+246.8%
44	Qube Research & Technologies Ltd#44 · 9,673 sh	9,673	$20.1M	0.02%	+852.1%
45	SPEECE THORSON CAPITAL GROUP#45 · 9,215 sh	9,215	$19.1M	4.08%	-1.9%
46	WELLS FARGO & COMPANY#46 · 8,710 sh	8,710	$18.1M	<0.01%	-0.8%
47	Bank of New York Mellon#47 · 8,412 sh	8,412	$17.4M	<0.01%	-0.4%
48	SEI INVESTMENTS#48 · 8,108 sh	8,108	$16.8M	0.01%	-26.9%
49	GW&K Investment Management#49 · 7,839 sh	7,839	$16.3M	0.13%	-1.1%
50	THOMPSON SIEGEL & WALMSLEY#50 · 7,656 sh	7,656	$15.9M	0.28%	+6.2%
51	ARROWSTREET CAPITAL, LIMITED PARTNERSHIP#51 · 7,284 sh	7,284	$15.1M	<0.01%	+280.8%
52	CITADEL ADVISORS#52 · 7,136 sh	7,136	$14.8M	<0.01%	+174.1%
53	HOTCHKIS & WILEY CAPITAL MANAGEMENT#53 · 6,788 sh	6,788	$14.1M	0.04%	+12.2%
54	ROYCE & ASSOCIATES#54 · 6,781 sh	6,781	$14.1M	0.11%	+5.0%
55	HRT FINANCIAL#55 · 6,760 sh	6,760	$14.0M	0.04%	+184.6%
56	D. E. Shaw#56 · 6,618 sh	6,618	$13.7M	<0.01%	-25.7%
57	Edgestream Partners, L.P.#57 · 6,578 sh	6,578	$13.6M	0.41%	+110.2%
58	JPMORGAN CHASE#58 · 5,410 sh	5,410	$11.5M	<0.01%	+110.8%
59	AQR CAPITAL MANAGEMENT#59 · 5,450 sh	5,450	$11.3M	<0.01%	-29.6%
60	CALIFORNIA PUBLIC EMPLOYEES RETIREMENT SYSTEM#60 · 5,248 sh	5,248	$10.9M	<0.01%	-18.2%
61	Williams Jones Wealth Management#61 · 5,193 sh	5,193	$10.8M	0.12%	0.0%
62	Swiss National Bank#62 · 4,826 sh	4,826	$10.0M	<0.01%	-4.2%
63	WINMILL#63 · 4,800 sh	4,800	$10.0M	2.20%	New
64	FRANKLIN RESOURCES#64 · 4,178 sh	4,178	$8.7M	<0.01%	-12.9%
65	Phocas Financial#65 · 4,078 sh	4,078	$8.5M	1.17%	-5.0%
66	RHUMBLINE ADVISERS#66 · 3,898 sh	3,898	$8.1M	<0.01%	-5.7%
67	Creative Planning#67 · 3,861 sh	3,861	$8.0M	<0.01%	-4.6%
68	Nuveen#68 · 3,679 sh	3,679	$7.6M	<0.01%	-14.6%
69	Invesco Ltd.#69 · 3,497 sh	3,497	$7.3M	<0.01%	+17.9%
70	LEE DANNER & BASS#70 · 3,253 sh	3,253	$6.7M	0.39%	+1.6%
71	AMERIPRISE FINANCIAL#71 · 2,852 sh	2,852	$5.9M	<0.01%	-0.5%
72	NEW YORK STATE COMMON RETIREMENT FUND#72 · 2,532 sh	2,532	$5.2M	<0.01%	+0.8%
73	Triad Investment Management#73 · 2,471 sh	2,471	$5.1M	—	-67.6%
74	VANGUARD ASSET MANAGEMENT, Ltd#74 · 2,392 sh	2,392	$5.0M	<0.01%	+2.9%
75	Russell Investments Group, Ltd.#75 · 2,369 sh	2,369	$4.9M	<0.01%	+107.4%
76	STATE BOARD OF ADMINISTRATION OF FLORIDA RETIREMENT SYSTEM#76 · 2,351 sh	2,351	$4.9M	<0.01%	+4.0%
77	PRICE T ROWE ASSOCIATES#77 · 2,335 sh	2,335	$4.8M	<0.01%	+5.6%
78	Legal & General Group Plc#78 · 2,257 sh	2,257	$4.7M	<0.01%	-6.3%
79	Robeco Institutional Asset Management B.V.#79 · 2,184 sh	2,184	$4.5M	—	+0.2%
80	Regency Capital Management \DE#80 · 2,146 sh	2,146	$4.4M	1.77%	+39.8%
81	DAVENPORT#81 · 2,123 sh	2,123	$4.4M	—	0.0%
82	BRADLEY FOSTER & SARGENT#82 · 1,899 sh	1,899	$3.9M	0.06%	New
83	PARSONS CAPITAL MANAGEMENT#83 · 1,887 sh	1,887	$3.9M	0.18%	-0.1%
84	Lighthouse Investment Partners#84 · 1,868 sh	1,868	$3.9M	0.11%	New
85	Cerity Partners#85 · 1,797 sh	1,797	$3.7M	<0.01%	-3.7%
86	Union Bankshares#86 · 1,765 sh	1,765	$3.7M	0.06%	0.0%
87	MML INVESTORS SERVICES#87 · 1,741 sh	1,741	$3.6M	<0.01%	-29.2%
88	AGF MANAGEMENT LTD#88 · 1,696 sh	1,696	$3.5M	0.01%	-0.4%
89	XTX Topco Ltd#89 · 1,644 sh	1,644	$3.4M	0.04%	+557.6%
90	Toroso Investments#90 · 1,578 sh	1,578	$3.3M	<0.01%	+17.1%
91	Focus Partners Wealth#91 · 1,553 sh	1,553	$3.2M	<0.01%	+37.6%
92	ExodusPoint Capital Management#92 · 1,443 sh	1,443	$3.0M	0.02%	+136.2%
93	OPPENHEIMER ASSET MANAGEMENT#93 · 1,356 sh	1,356	$2.8M	0.03%	-8.4%
94	LPL Financial#94 · 1,318 sh	1,318	$2.7M	<0.01%	-5.5%
95	HighTower Advisors#95 · 1,316 sh	1,316	$2.7M	<0.01%	-9.1%
96	ROYAL BANK OF CANADA#96 · 1,237 sh	1,237	$2.6M	<0.01%	+3.5%
97	STIFEL FINANCIAL#97 · 1,235 sh	1,235	$2.6M	<0.01%	-4.6%
98	WCM INVESTMENT MANAGEMENT#98 · 1,197 sh	1,197	$2.5M	<0.01%	-80.0%
99	1834 INVESTMENT ADVISORS#99 · 1,176 sh	1,176	$2.4M	—	0.0%
100	BNP PARIBAS FINANCIAL MARKETS#100 · 1,169 sh	1,169	$2.4M	<0.01%	-82.3%

Funds that sold out of WTM in Q2 2026 (45)

Held WTM at the end of Q1 2026 and filed a Q2 2026 13F without it. Not in the list above, because they no longer hold it. Largest prior position first.

Institutions that held WTM in Q1 2026 and reported no position in Q2 2026.
Institution	Shares sold	Value in Q1 2026
SUSQUEHANNA INTERNATIONAL GROUP, LLP10,965 sh	10,965	$24.1M
Select Equity Group, L.P.10,560 sh	10,560	$23.2M
MARSHALL WACE, LLP3,878 sh	3,878	$8.5M
RENAISSANCE TECHNOLOGIES2,611 sh	2,611	$5.7M
DARK FOREST CAPITAL MANAGEMENT2,255 sh	2,255	$5.0M
DIVERSIFIED MANAGEMENT1,158 sh	1,158	$2.5M
Capula Management Ltd921 sh	921	$2.0M
Fieldview Capital Management729 sh	729	$1.6M
Mariner607 sh	607	$1.3M
AMG National Bank571 sh	571	$1.3M
Entropy Technologies470 sh	470	$1.0M
Main Street Financial Solutions439 sh	439	$963.4K
Bridgewater Associates414 sh	414	$909.5K
NATIXIS356 sh	356	$782.1K
Caprock Group340 sh	340	$747.0K
Private Advisor Group213 sh	213	$468.0K
Evercore Wealth Management200 sh	200	$439.4K
BROWN BROTHERS HARRIMAN199 sh	199	$437.2K
IEQ CAPITAL198 sh	198	$435.0K
State of Wyoming179 sh	179	$393.3K
UNITED CAPITAL FINANCIAL ADVISORS166 sh	166	$364.7K
KEYBANK NATIONAL ASSOCIATION161 sh	161	$353.7K
ZACKS INVESTMENT MANAGEMENT157 sh	157	$344.9K
CreativeOne Wealth150 sh	150	$329.5K
Chapman Investment Management143 sh	143	$314.2K
CIBC Asset Management124 sh	124	$272.4K
Weiss Asset Management120 sh	120	$263.6K
Catalyst Funds Management Pty Ltd110 sh	110	$241.7K
SAGESPRING WEALTH PARTNERS101 sh	101	$221.2K
Focus Partners Advisor Solutions99 sh	99	$217.5K
Connecticut Capital Management Group94 sh	94	$206.5K
MAI Capital Management81 sh	81	$178.0K
Anchor Investment Management50 sh	50	$109.8K
Advisory Services Network37 sh	37	$81.3K
Opal Wealth Advisors20 sh	20	$43.9K
CX Institutional19 sh	19	$42.0K
Global Assets Advisory15 sh	15	$33.0K
Hillsdale Investment Management8 sh	8	$17.6K
Root Financial Partners4 sh	4	$8.8K
Parkside Financial Bank3 sh	3	$6.6K
Crewe Advisors3 sh	3	$6.6K
TWIN PEAKS WEALTH ADVISORS3 sh	3	$6.6K
SHP Wealth Management1 sh	1	$2.2K
Bare Financial Services1 sh	1	$2.2K
FIRST HORIZON NATIONAL1 sh	1	$2.2K

Source: Form 13F-HR filings on SEC EDGAR, Q2 2026. Values are as reported by each manager at quarter end. “% of portfolio” is the position’s share of the manager’s total reported 13F value for the same quarter. “New” means the manager filed a 13F for Q1 2026 without this position; a dash means no comparison is available. Where a manager’s own filing is internally inconsistent its value is withheld and it is listed last. 13F data shows reported holdings, not recommendations.