白山保險集團有限公司
US ˙ NYSE ˙ BMG9618E1075

SecurityWTM / White Mountains Insurance Group, Ltd.
InstitutionVanguard Group Inc
Latest Disclosed Ownership0 shares
Ownership 0.00%
Vanguard Group Inc ownership in WTM / White Mountains Insurance Group, Ltd.

2026-03-27 - Vanguard Group Inc has filed an SCHEDULE 13G/A form with the Securities and Exchange Commission (SEC) disclosing ownership of 0 shares of White Mountains Insurance Group, Ltd. (US:WTM). This represents 0.0 percent ownership of the company. In their previous filing dated 2024-02-13 , Vanguard Group Inc had reported owning 253,419 shares, indicating a decrease of -100.00 percent.

Institutional Ownership: 13D/G Filings

This table shows a history of the 13D/G filings made by the investor and/or investor group. Note that the share values in this table are not directly comparable to any numbers shown in the 13F table (if any).

File
Date		Effective
Date		Form Prev
Shares		 Latest
Shares		 ΔShares
(Percent)		 Ownership
(Percent)		 ΔOwnership
(Percent)
2026-03-27 2026-03-27 13G/A 253,419 0 -100.00 0.00 -100.00
2024-02-13 2024-02-13 13G/A 257,153 253,419 -1.45 9.90 -1.10
2023-03-10 2023-03-10 13G/A 253,921 257,153 1.27 10.01 1.52
2023-02-09 2023-02-09 13G/A 279,362 253,921 -9.11 9.86 6.48
2022-02-10 2022-02-10 13G/A 280,939 279,362 -0.56 9.26 2.21
2021-02-10 2021-02-10 13G/A 316,058 280,939 -11.11 9.06 -9.67
2020-03-06 2020-03-06 13G/A 312,836 316,058 1.03 10.03 2.14
2020-02-12 2020-02-12 13G/A 285,301 312,836 9.65 9.82 9.60
2019-02-11 2019-02-11 13G/A 287,826 285,301 -0.88 8.96 16.82
2018-02-08 2018-02-08 13G/A 300,497 287,826 -4.22 7.67 16.57
2017-02-10 2017-02-10 13G/A 306,253 300,497 -1.88 6.58 22.30
2016-02-11 2016-02-11 13G 306,253 5.38

Important Note: One of the primary uses of the 13D/G filings is to evaluate the ability of a firm to control a company (ie, the "beneficial ownership"). To that end, firms are required to report not just direct holdings in companies, but indirect holdings that they control. For investment firms, these indirect holdings can include shares in funds they manage, advisory accounts, and in the case of activist campaigns, pledged votes. Therefore, share counts listed in 13D/G filings can differ significantly than share counts listed in 13F filings.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

Upgrade to unlock premium data and export to Excel .

Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-01-29 2025-12-31 13F WHITE MTNS INS GROUP COM G9618E107 235,698 -11,306 -4.58 489,788 18.63 0.0071
2025-11-07 2025-09-30 13F WHITE MTNS INS GROUP COM G9618E107 247,004 -2,166 -0.87 412,872 -7.73 0.0062
2025-08-11 2025-06-30 13F WHITE MTNS INS GROUP COM G9618E107 249,170 -946 -0.38 447,440 -7.11 0.0072
2025-05-09 2025-03-31 13F WHITE MTNS INS GROUP COM G9618E107 250,116 -1,623 -0.64 481,676 -1.63 0.0087
2025-02-11 2024-12-31 13F WHITE MTNS INS GROUP COM G9618E107 251,739 956 0.38 489,647 15.11 0.0085
2024-11-13 2024-09-30 13F WHITE MTNS INS GROUP COM G9618E107 250,783 -252 -0.10 425,378 -6.77 0.0076
2024-08-13 2024-06-30 13F WHITE MTNS INS GROUP COM G9618E107 251,035 -895 -0.36 456,244 0.93 0.0088
2024-05-10 2024-03-31 13F WHITE MTNS INS GROUP COM G9618E107 251,930 -1,489 -0.59 452,038 18.52 0.0090
2024-03-11 2023-12-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 253,419 26 0.01 381,398 0.63 0.0083
2024-02-14 2023-12-31 13F WHITE MTNS INS GROUP COM G9618E107 253,419 26 381,398 0.0072
2023-12-18 2023-09-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 253,393 -222 -0.09 378,997 7.59 0.0093
2023-11-14 2023-09-30 13F WHITE MTNS INS GROUP COM G9618E107 253,393 -222 378,997 0.0017
2023-08-14 2023-06-30 13F WHITE MTNS INS GROUP COM G9618E107 253,615 -4,362 -1.69 352,248 -0.88 0.0084
2023-07-14 2023-03-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 257,977 4,056 1.60 355,361 -1.05 0.0090
2023-05-15 2023-03-31 13F WHITE MTNS INS GROUP COM G9618E107 257,977 4,056 355,361 0.0019
2023-02-10 2022-12-31 13F WHITE MTNS INS GROUP COM G9618E107 253,921 4,689 1.88 359,128 10.58 0.0098
2022-11-14 2022-09-30 13F WHITE MTNS INS GROUP COM G9618E107 249,232 -30,322 -10.85 324,755 -6.78 0.0096
2022-08-12 2022-06-30 13F WHITE MTNS INS GROUP COM G9618E107 279,554 -1,005 -0.36 348,362 9.28 0.0098
2022-05-13 2022-03-31 13F WHITE MTNS INS GROUP COM G9618E107 280,559 1,197 0.43 318,782 12.55 0.0075
2022-02-14 2021-12-31 13F WHITE MTNS INS GROUP COM G9618E107 279,362 -6,700 -2.34 283,246 -7.43 0.0064
2021-11-12 2021-09-30 13F WHITE MTNS INS GROUP COM G9618E107 286,062 -3,252 -1.12 305,975 -7.88 0.0076
2021-08-13 2021-06-30 13F WHITE MTNS INS GROUP COM G9618E107 289,314 -6,038 -2.04 332,141 0.87 0.0083
2021-05-14 2021-03-31 13F WHITE MTNS INS GROUP COM G9618E107 295,352 14,413 5.13 329,289 17.13 0.0089
2021-02-12 2020-12-31 13F WHITE MTNS INS GROUP COM G9618E107 280,939 3,164 1.14 281,125 29.92 0.0082
2020-11-16 2020-09-30 13F WHITE MTNS INS GROUP COM G9618E107 277,775 -16,089 -5.47 216,386 -17.08 0.0072
2020-08-14 2020-06-30 13F WHITE MTNS INS GROUP COM G9618E107 293,864 -26,999 -8.41 260,942 -10.63 0.0093
2020-05-15 2020-03-31 13F WHITE MTNS INS GROUP COM G9618E107 320,863 8,027 2.57 291,984 -16.33 0.0124
2020-02-14 2019-12-31 13F WHITE MTNS INS GROUP COM G9618E107 312,836 8,986 2.96 348,972 6.34 0.0119
2019-11-14 2019-09-30 13F WHITE MTNS INS GROUP COM G9618E107 303,850 4,622 1.54 328,158 7.36 0.0122
2019-08-14 2019-06-30 13F WHITE MTNS INS GROUP COM G9618E107 299,228 788 0.26 305,650 10.66 0.0115
2019-05-15 2019-03-31 13F WHITE MTNS INS GROUP COM G9618E107 298,440 13,139 4.61 276,201 12.87 0.0108
2019-02-14 2018-12-31 13F WHITE MTNS INS GROUP COM G9618E107 285,301 6,035 2.16 244,700 -6.37 0.0110
2018-12-13 2018-09-30 13F/A-2 WHITE MTNS INS GROUP COM G9618E107 279,266 8,080 2.98 261,356 6.30 0.0102
2018-11-23 2018-09-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 279,266 0 261,356 0.0102
2018-11-14 2018-09-30 13F WHITE MTNS INS GROUP COM G9618E107 279,266 8,080 261,356
2018-08-14 2018-06-30 13F WHITE MTNS INS GROUP COM G9618E107 271,186 -33,930 -11.12 245,860 -2.03 0.0103
2018-05-15 2018-03-31 13F WHITE MTNS INS GROUP COM G9618E107 305,116 17,290 6.01 250,964 2.43 0.0110
2018-02-14 2017-12-31 13F WHITE MTNS INS GROUP COM G9618E107 287,826 13,382 4.88 245,021 4.18 0.0107
2017-11-14 2017-09-30 13F WHITE MTNS INS GROUP COM G9618E107 274,444 -43,948 -13.80 235,198 -14.96 0.0110
2017-08-24 2017-06-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 318,392 4,178 1.33 276,566 0.03 0.0136
2017-08-11 2017-06-30 13F WHITE MTNS INS GROUP COM G9618E107 318,392 4,178 276,566
2017-05-12 2017-03-31 13F WHITE MTNS INS GROUP COM G9618E107 314,214 13,717 4.56 276,471 10.05 0.0142
2017-02-14 2016-12-31 13F WHITE MTNS INS GROUP COM G9618E107 300,497 2,874 0.97 251,231 1.70 0.0140
2016-11-14 2016-09-30 13F WHITE MTNS INS GROUP COM G9618E107 297,623 11,083 3.87 247,027 2.39 0.0145
2016-08-10 2016-06-30 13F WHITE MTNS INS GROUP COM G9618E107 286,540 -27,247 -8.68 241,268 -4.20 0.0150
2016-05-13 2016-03-31 13F WHITE MTNS INS GROUP COM G9618E107 313,787 7,534 2.46 251,846 13.14 0.0163
2016-02-08 2015-12-31 13F WHITE MTNS INS GROUP COM G9618E107 306,253 -1,669 -0.54 222,588 -3.27 0.0150
2015-11-12 2015-09-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 307,922 17,839 6.15 230,111 21.12 0.0098
2015-11-12 2015-09-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 307,922 17,839 230,111 0.0098
2015-08-13 2015-06-30 13F WHITE MTNS INS GROUP COM G9618E107 290,083 10,285 3.68 189,987 -0.80 0.0128
2015-05-15 2015-03-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 279,798 11,807 4.41 191,527 13.42 0.0130
2015-05-14 2015-03-31 13F WHITE MTNS INS GROUP COM G9618E107 279,798 191,527
2015-02-12 2014-12-31 13F WHITE MTNS INS GROUP COM G9618E107 267,991 2,566 0.97 168,863 0.97 0.0122
2014-11-12 2014-09-30 13F WHITE MTNS INS GROUP COM G9618E107 265,425 16,300 6.54 167,237 10.33 0.0130
2014-08-11 2014-06-30 13F WHITE MTNS INS GROUP COM G9618E107 249,125 6,425 2.65 151,578 4.11 0.0119
2014-05-13 2014-03-31 13F WHITE MTNS INS GROUP COM G9618E107 242,700 7,654 3.26 145,596 2.71 0.0122
2014-02-12 2013-12-31 13F WHITE MTNS INS GROUP COM G9618E107 235,046 20,388 9.50 141,752 16.34 0.0125
2013-11-07 2013-09-30 13F WHITE MTNS INS GROUP COM G9618E107 214,658 5,573 2.67 121,844 1.36 0.0119
2013-08-13 2013-06-30 13F WHITE MTNS INS GROUP COM G9618E107 209,085 209,085 120,211 0.0126
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.