白山保險集團有限公司
US ˙ NYSE ˙ BMG9618E1075

SecurityWTM / White Mountains Insurance Group, Ltd.
InstitutionMorgan Stanley
Latest Disclosed Ownership76,817 shares
Ownership 3.00%
Morgan Stanley ownership in WTM / White Mountains Insurance Group, Ltd.

2026-02-12 - Morgan Stanley has filed an SCHEDULE 13G/A form with the Securities and Exchange Commission (SEC) disclosing ownership of 76,817 shares of White Mountains Insurance Group, Ltd. (US:WTM). This represents 3.0 percent ownership of the company. In their previous filing dated 2025-11-07 , Morgan Stanley had reported owning 132,638 shares, indicating a decrease of -42.09 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)
2026-02-12 2026-02-12 13G/A 132,638 76,817 -42.09 3.00 -42.31
2025-11-07 2025-11-07 13G/A 159,020 132,638 -16.59 5.20 -16.13
2025-08-07 2025-08-07 13G/A 185,611 159,020 -14.33 6.20 -13.89
2024-02-09 2024-02-09 13G/A 180,369 185,611 2.91 7.20 2.86
2023-02-10 2023-02-10 13G/A 186,905 180,369 -3.50 7.00 12.90
2022-02-11 2022-02-11 13G/A 192,437 186,905 -2.87 6.20 -3.13
2021-12-10 2021-12-10 13G/A 192,437 6.40

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.

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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)
2026-05-15 2026-03-31 13F WHITE MTNS INS GROUP COM G9618E107 59,295 -22,856 -27.82 130,274 -23.69 0.0078
2026-05-27 2025-12-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 82,151 -56,711 -40.84 170,716 -26.45 0.0102
2026-02-13 2025-12-31 13F WHITE MTNS INS GROUP COM G9618E107 82,151 -56,711 170,716 0.0102
2026-05-27 2025-09-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 138,862 -26,202 -15.87 232,114 -21.69 0.0141
2025-11-14 2025-09-30 13F WHITE MTNS INS GROUP COM G9618E107 138,862 -26,202 232,114 0.0141
2025-08-15 2025-06-30 13F WHITE MTNS INS GROUP COM G9618E107 165,064 -5,567 -3.26 296,411 -9.80 0.0193
2025-05-15 2025-03-31 13F WHITE MTNS INS GROUP COM G9618E107 170,631 -7,060 -3.97 328,607 -4.92 0.0235
2025-05-15 2024-12-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 177,691 -1,346 -0.75 345,623 13.81 0.0242
2025-02-14 2024-12-31 13F WHITE MTNS INS GROUP COM G9618E107 177,691 -1,346 345,623 0.0242
2025-05-14 2024-09-30 13F/A-2 WHITE MTNS INS GROUP COM G9618E107 179,037 -5,898 -3.19 303,686 -9.65 0.0220
2025-02-14 2024-09-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 179,037 -5,898 303,686 0.0220
2024-11-14 2024-09-30 13F WHITE MTNS INS GROUP COM G9618E107 179,037 -5,898 303,686 0.0220
2025-05-14 2024-06-30 13F/A-2 WHITE MTNS INS GROUP COM G9618E107 184,935 -595 -0.32 336,113 0.97 0.0260
2024-10-17 2024-06-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 184,935 -595 336,113 0.0260
2024-08-14 2024-06-30 13F WHITE MTNS INS GROUP COM G9618E107 184,935 -595 336,113 0.0260
2024-10-17 2024-03-31 13F/A-2 WHITE MTNS INS GROUP COM G9618E107 185,530 -12,471 -6.30 332,898 11.71 0.0267
2024-08-16 2024-03-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 185,530 -12,471 332,898 0.0031
2024-05-15 2024-03-31 13F WHITE MTNS INS GROUP COM G9618E107 185,530 -12,471 332,898 0.0267
2024-08-16 2023-12-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 198,001 -4,922 -2.43 297,996 -1.82 0.0263
2024-02-13 2023-12-31 13F WHITE MTNS INS GROUP COM G9618E107 198,001 -4,922 297,996 0.0263
2023-11-15 2023-09-30 13F WHITE MTNS INS GROUP COM G9618E107 202,923 914 0.45 303,512 8.18 0.0309
2023-08-14 2023-06-30 13F WHITE MTNS INS GROUP COM G9618E107 202,009 1,110 0.55 280,574 1.39 0.0277
2023-05-15 2023-03-31 13F WHITE MTNS INS GROUP COM G9618E107 200,899 11,228 5.92 276,736 3.16 0.0297
2023-02-14 2022-12-31 13F WHITE MTNS INS GROUP COM G9618E107 189,671 166,320 712.26 268,257 781.64 0.0305
2022-11-14 2022-09-30 13F WHITE MTNS INS GROUP COM G9618E107 23,351 703 3.10 30,427 7.81 0.0041
2022-10-27 2022-06-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 22,648 18,662 468.19 28,224 523.18 0.0037
2022-08-15 2022-06-30 13F WHITE MTNS INS GROUP COM G9618E107 22,648 18,662 28,224 0.0037
2022-10-27 2022-03-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 3,986 253 6.78 4,529 19.66 0.0006
2022-05-13 2022-03-31 13F WHITE MTNS INS GROUP COM G9618E107 3,986 253 4,529 0.0006
2022-02-14 2021-12-31 13F WHITE MTNS INS GROUP COM G9618E107 3,733 -1,143 -23.44 3,785 -27.45 0.0005
2021-11-15 2021-09-30 13F WHITE MTNS INS GROUP COM G9618E107 4,876 282 6.14 5,217 -1.08 0.0007
2021-08-23 2021-06-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 4,594 -758 -14.16 5,274 -11.60 0.0007
2021-08-16 2021-06-30 13F WHITE MTNS INS GROUP COM G9618E107 4,594 -758 5,274 0.0001
2021-05-17 2021-03-31 13F WHITE MTNS INS GROUP COM G9618E107 5,352 2,547 90.80 5,966 112.62 0.0009
2021-02-16 2020-12-31 13F WHITE MTNS INS GROUP COM G9618E107 2,805 -3,334 -54.31 2,806 -41.32 0.0004
2020-11-13 2020-09-30 13F WHITE MTNS INS GROUP COM G9618E107 6,139 3,256 112.94 4,782 86.80 0.0009
2020-08-14 2020-06-30 13F WHITE MTNS INS GROUP COM G9618E107 2,883 -1,351 -31.91 2,560 -33.54 0.0006
2020-05-26 2020-03-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 4,234 979 30.08 3,852 6.09 0.0010
2020-05-15 2020-03-31 13F WHITE MTNS INS GROUP COM G9618E107 4,234 979 3,852 295.9139
2020-02-14 2019-12-31 13F WHITE MTNS INS GROUP COM G9618E107 3,255 795 32.32 3,631 36.66 0.0008
2019-11-14 2019-09-30 13F WHITE MTNS INS GROUP COM G9618E107 2,460 -28 -1.13 2,657 4.52 0.0007
2019-08-14 2019-06-30 13F WHITE MTNS INS GROUP COM G9618E107 2,488 -101 -3.90 2,542 6.09 0.0007
2019-05-15 2019-03-31 13F WHITE MTNS INS GROUP COM G9618E107 2,589 -2,814 -52.08 2,396 -48.30 0.0007
2019-02-14 2018-12-31 13F WHITE MTNS INS GROUP COM G9618E107 5,403 1,891 53.84 4,634 41.02 0.0014
2019-04-23 2018-09-30 13F/A-2 WHITE MTNS INS GROUP COM G9618E107 3,512 -3,757 -51.69 3,286 -50.14 0.0008
2018-11-20 2018-09-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 3,512 0 3,286 0.0008
2018-11-14 2018-09-30 13F WHITE MTNS INS GROUP COM G9618E107 3,512 -3,757 3,286
2019-04-23 2018-06-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 7,269 4,437 156.67 6,590 182.95 0.0018
2018-08-14 2018-06-30 13F WHITE MTNS INS GROUP COM G9618E107 7,269 4,437 6,590
2019-04-23 2018-03-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 2,832 552 24.21 2,329 20.05 0.0006
2018-05-14 2018-03-31 13F WHITE MTNS INS GROUP COM G9618E107 2,832 552 2,329
2019-04-23 2017-12-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 2,280 88 4.01 1,940 3.30 0.0005
2018-02-14 2017-12-31 13F WHITE MTNS INS GROUP COM G9618E107 2,280 88 1,940
2017-11-14 2017-09-30 13F WHITE MTNS INS GROUP COM G9618E107 2,192 -6,632 -75.16 1,878 -75.50 0.0006
2017-08-11 2017-06-30 13F WHITE MTNS INS GROUP COM G9618E107 8,824 233 2.71 7,664 1.39 0.0023
2017-05-22 2017-03-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 8,591 1,873 27.88 7,559 34.57 0.0023
2017-05-12 2017-03-31 13F WHITE MTNS INS GROUP COM G9618E107 8,591 7,559
2017-02-22 2016-12-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 6,718 4,780 246.65 5,617 249.10 0.0018
2017-02-13 2016-12-31 13F WHITE MTNS INS GROUP COM G9618E107 6,718 5,617
2016-11-10 2016-09-30 13F WHITE MTNS INS GROUP COM G9618E107 1,938 -1,094 -36.08 1,609 -36.98 0.0005
2016-08-12 2016-06-30 13F WHITE MTNS INS GROUP COM G9618E107 3,032 -4 -0.13 2,553 4.80 0.0009
2016-05-12 2016-03-31 13F WHITE MTNS INS GROUP COM G9618E107 3,036 -711 -18.98 2,436 -10.54 0.0009
2016-02-09 2015-12-31 13F WHITE MTNS INS GROUP COM G9618E107 3,747 1,211 47.75 2,723 43.69 0.0010
2016-02-08 2015-09-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 2,536 -339 -11.79 1,895 0.69 0.0007
2015-11-09 2015-09-30 13F WHITE MTNS INS GROUP COM G9618E107 2,536 1,895
2015-08-12 2015-06-30 13F WHITE MTNS INS GROUP COM G9618E107 2,875 989 52.44 1,882 45.78 0.0007
2015-05-14 2015-03-31 13F WHITE MTNS INS GROUP COM G9618E107 1,886 -1,153 -37.94 1,291 -32.58 0.0005
2015-02-13 2014-12-31 13F WHITE MTNS INS GROUP COM G9618E107 3,039 -1,868 -38.07 1,915 -38.09 0.0007
2014-12-16 2014-09-30 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 4,907 3,478 243.39 3,093 255.52 0.0012
2014-11-14 2014-09-30 13F WHITE MTNS INS GROUP COM G9618E107 4,907 3,093
2014-08-12 2014-06-30 13F WHITE MTNS INS GROUP COM G9618E107 1,429 -11,708 -89.12 870 -88.96 0.0015
2014-05-13 2014-03-31 13F WHITE MTNS INS GROUP COM G9618E107 13,137 8,523 184.72 7,880 183.15 0.0033
2014-02-13 2013-12-31 13F WHITE MTNS INS GROUP COM G9618E107 4,614 -773 -14.35 2,783 -9.02 0.0012
2013-11-13 2013-09-30 13F WHITE MOUNTAINS INSURAN COM G9618E107 5,387 -1,210 -18.34 3,059 -19.35 0.0014
2013-08-08 2013-06-30 13F WHITE MOUNTAINS INSURAN COM G9618E107 6,597 6,597 3,793 0.0019
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.