WHITE MTNS INS GROUP LTD (G9618E107) Top Institutional Shareholders
WHITE MTNS INS GROUP LTD (G9618E107) is currently reported in institutional portfolios tracked by InsiderSet based on the latest available SEC Form 13F filings for the quarter ended March 31, 2026. The institutional investors covered on this page collectively reported approximately $4.61B in G9618E107 holdings during the latest filing period.
Dimensional Fund Advisors Lp is currently the largest disclosed institutional shareholder of G9618E107 tracked by InsiderSet, reporting ownership valued at approximately $344.08M in its March 31, 2026 SEC Form 13F filing.
The top 10 institutional shareholders tracked on this page collectively account for approximately 53% of the total disclosed G9618E107 value among the investors covered in this analysis. Major shareholders include Dimensional Fund Advisors Lp, Neuberger Berman Group Llc, River Road Asset Management, Llc, and several other long-term asset managers with concentrated positions in WHITE MTNS INS GROUP LTD (G9618E107).
This page ranks the largest institutional G9618E107 shareholders using publicly disclosed SEC Form 13F data, including reported values, estimated current holding values, portfolio allocation percentages, ownership concentration metrics, and historical holding changes across major hedge funds and investment firms.
Institutional Holders
360
Total Reported Value
$4.61B
Largest Holder
Dimensional Fund Advisors Lp
Largest Position
$344.08M
Insider Transactions (90d)
0
Latest Filing Quarter
Q1 2026
New Institutional Positions
71
Funds Exiting Positions
0
| Name | Investor/Manager | Portfolio % | Quantity | Reported Balance | Current Estimated Value | Gain/loss Since Filing | Estimated Portfolio Performance |
|---|---|---|---|---|---|---|---|
| Dimensional Fund Advisors Lp | 0.07% | 156,618 | $344,084,166 | — | — | — | |
| Neuberger Berman Group Llc | 0.21% | 124,715 | $273,993,893 | — | — | — | |
| River Road Asset Management, Llc | 3.00% | 120,519 | $264,775,422 | — | — | — | |
| Vanguard Portfolio Management Llc | 0.01% | 115,553 | $253,865,319 | — | — | — | |
| Blackrock, Inc. | 0.00% | 113,328 | $248,976,061 | — | — | — | |
| Vanguard Capital Management Llc | 0.01% | 109,157 | $239,813,563 | — | — | — | |
| Cooke & Bieler Lp | 2.61% | 104,857 | $230,366,635 | — | — | — | |
| Fuller & Thaler Asset Management, Inc. | 0.77% | 104,561 | $229,715,563 | — | — | — | |
| Fiduciary Management Inc | 2.32% | 85,066 | $186,886,599 | — | — | — | |
| Wallace Capital Management Inc. | 19.88% | 78,795 | $173,109,162 | — | — | — | |
| Morgan Stanley | 0.01% | 59,295 | $130,273,576 | — | — | — | |
| Boston Partners | 0.13% | 57,459 | $126,222,446 | — | — | — | |
| London Co Of Virginia | 0.77% | 57,131 | $125,537,405 | — | — | — | |
| State Street Corp | 0.00% | 49,158 | $107,998,160 | — | — | — | |
| Geode Capital Management, Llc | 0.01% | 42,119 | $92,559,204 | — | — | — | |
| Gendell Jeffrey L | 1.13% | 37,814 | $83,075,845 | — | — | — | |
| Reinhart Partners, Llc. | 2.36% | 37,374 | $82,148,044 | — | — | — | |
| Bank Of America Corp | 0.00% | 28,358 | $62,301,392 | — | — | — | |
| Cannell & Spears Llc | 1.22% | 28,027 | $61,573,306 | — | — | — | |
| Charles Schwab Investment Management Inc | 0.01% | 24,241 | $53,256,507 | — | — | — | |
| Raymond James Financial Inc | 0.02% | 23,951 | $52,619,460 | — | — | — | |
| Mraz, Amerine & Associates, Inc. | 7.18% | 22,179 | $48,726,795 | — | — | — | |
| Longleaf Partners | Mason Hawkins | 2.04% | 18,864 | $41,443,454 | — | — | — |
| Allspring Global Investments Holdings, Llc | 0.07% | 18,612 | $40,545,125 | — | — | — | |
| Brown Advisory Inc | 0.06% | 17,844 | $39,204,871 | — | — | — | |
| Goldman Sachs Group Inc | 0.00% | 15,783 | $34,674,639 | — | — | — | |
| Envestnet Asset Management Inc | 0.01% | 15,563 | $34,191,207 | — | — | — | |
| Northern Trust Corp | 0.00% | 15,495 | $34,041,895 | — | — | — | |
| Vanguard Fiduciary Trust Co | 0.01% | 15,186 | $33,363,035 | — | — | — | |
| Wellington Management Group Llp | 0.01% | 14,884 | $32,699,553 | — | — | — | |
| Boussard & Gavaudan Investment Management Llp | 2.97% | 13,975 | $30,968,600 | — | — | — | |
| Jane Street Group, Llc | 0.03% | 13,808 | $30,335,624 | — | — | — | |
| Horizon Kinetics Asset Management Llc | 0.31% | 13,112 | $28,806,544 | — | — | — | |
| Elkhorn Partners Limited Partnership | 17.76% | 12,700 | $27,901,392 | — | — | — | |
| Victory Capital Management Inc | 0.02% | 11,145 | $24,485,119 | — | — | — | |
| Sei Investments Co | 0.02% | 11,098 | $24,381,869 | — | — | — | |
| Susquehanna International Group, Llp | 0.03% | 10,965 | $24,089,666 | — | — | — | |
| Select Equity Group, L.P. | 0.12% | 10,560 | $23,199,898 | — | — | — | |
| Ubs Group Ag | 0.00% | 10,441 | $22,938,460 | — | — | — | |
| Quantinno Capital Management Lp | 0.04% | 9,784 | $21,495,096 | — | — | — | |
| Gotham Asset Management, Llc | 0.06% | 9,047 | $19,875,897 | — | — | — | |
| D. E. Shaw & Co., Inc. | 0.02% | 8,910 | $19,574,914 | — | — | — | |
| Wells Fargo & Company/Mn | 0.00% | 8,782 | $19,292,758 | — | — | — | |
| Bank Of New York Mellon Corp | 0.00% | 8,444 | $18,550,130 | — | — | — | |
| American Century Companies Inc | 0.01% | 8,308 | $18,252,344 | — | — | — | |
| Ubs Am, A Distinct Business Unit Of Ubs Asset Management Americas Llc | 0.00% | 7,826 | $17,193,410 | — | — | — | |
| Aqr Capital Management Llc | 0.01% | 7,738 | $17,000,160 | — | — | — | |
| Triad Investment Management | 6.05% | 7,627 | $16,427,100 | — | — | — | |
| Bnp Paribas Financial Markets | 0.01% | 6,623 | $14,550,466 | — | — | — | |
| Royce & Associates Lp | 0.14% | 6,460 | $14,192,362 | — | — | — |
Frequently asked questions about G9618E107
Who owns the most G9618E107 stock?
The largest holders of G9618E107 are typically major institutional investors such as asset managers and hedge funds reporting on Form 13F. The table above ranks tracked superinvestors by reported position size using the latest available filings for WHITE MTNS INS GROUP LTD (G9618E107).
Is G9618E107 widely held by superinvestors?
Many widely followed stocks like G9618E107 appear across numerous superinvestor portfolios because of liquidity, index inclusion, and fundamentals. The holder count and table above show how broadly G9618E107 is represented among the institutional managers we track.
What do “Current Estimated Value”, “Gain/loss Since Filing”, and “Estimated Portfolio Performance” mean?
Current Estimated Value is reported share quantity from the latest 13F times our most recent split-adjusted U.S. session close. Gain/loss Since Filing is that estimate minus the reported 13F dollar value; Estimated Portfolio Performance is that difference as a percent of the reported value. Green means the estimate is above the filing value; red means below (not purchase cost). If many filers share the same implied filing price per share, the performance % may match across rows. These are not official fund marks or live quotes.