White Mountains Insurance Group, Ltd.
US ˙ NYSE ˙ BMG9618E1075

SecurityWTM / White Mountains Insurance Group, Ltd.
InstitutionDimensional Fund Advisors Lp
Latest Disclosed Ownership161,957 shares
Ownership 6.30%
Dimensional Fund Advisors Lp ownership in WTM / White Mountains Insurance Group, Ltd.

2024-02-09 - Dimensional Fund Advisors Lp has filed an SC 13G/A form with the Securities and Exchange Commission (SEC) disclosing ownership of 161,957 shares of White Mountains Insurance Group, Ltd. (US:WTM). This represents 6.3 percent ownership of the company. In their previous filing dated 2023-02-10 , Dimensional Fund Advisors Lp had reported owning 160,079 shares, indicating an increase of 1.17 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)
2024-02-09 2024-02-09 13G/A 160,079 161,957 1.17 6.30 1.61
2023-02-10 2023-02-10 13G 160,079 6.20

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)
2026-05-07 2026-03-31 13F WHITE MTNS INS GROUP COM G9618E107 156,618 14 0.01 344,084 5.73 0.0154
2026-02-12 2025-12-31 13F WHITE MTNS INS GROUP COM G9618E107 156,604 -613 -0.39 325,428 23.83 0.0683
2025-11-12 2025-09-30 13F WHITE MTNS INS GROUP COM G9618E107 157,217 1,464 0.94 262,792 -6.04 0.0564
2025-08-12 2025-06-30 13F WHITE MTNS INS GROUP COM G9618E107 155,753 -864 -0.55 279,687 -7.27 0.0648
2025-05-13 2025-03-31 13F WHITE MTNS INS GROUP COM G9618E107 156,617 -778 -0.49 301,609 -1.48 0.0750
2025-02-13 2024-12-31 13F WHITE MTNS INS GROUP COM G9618E107 157,395 -1,139 -0.72 306,140 13.85 0.0735
2024-11-07 2024-09-30 13F WHITE MTNS INS GROUP COM G9618E107 158,534 -1,027 -0.64 268,907 -7.27 0.0652
2024-08-09 2024-06-30 13F WHITE MTNS INS GROUP COM G9618E107 159,561 -2,357 -1.46 289,987 -0.19 0.0757
2024-05-10 2024-03-31 13F WHITE MTNS INS GROUP COM G9618E107 161,918 -39 -0.02 290,529 19.19 0.0787
2024-02-07 2023-12-31 13F WHITE MTNS INS GROUP COM G9618E107 161,957 1,464 0.91 243,745 1.54 0.0712
2023-11-09 2023-09-30 13F WHITE MTNS INS GROUP COM G9618E107 160,493 1,868 1.18 240,051 8.96 0.0787
2023-08-09 2023-06-30 13F WHITE MTNS INS GROUP COM G9618E107 158,625 -1,313 -0.82 220,315 0.00 0.0702
2023-05-12 2023-03-31 13F WHITE MTNS INS GROUP COM G9618E107 159,938 -141 -0.09 220,313 97,383.63 0.0742
2023-02-09 2022-12-31 13F WHITE MTNS INS GROUP COM G9618E107 160,079 -886 -0.55 226 -99.89 0.0669
2022-11-10 2022-09-30 13F WHITE MTNS INS GROUP COM G9618E107 160,965 561 0.35 209,740 4.93 0.0805
2022-08-12 2022-06-30 13F WHITE MTNS INS GROUP COM G9618E107 160,404 5,851 3.79 199,882 13.82 0.0717
2022-05-13 2022-03-31 13F WHITE MTNS INS GROUP COM G9618E107 154,553 5,051 3.38 175,605 15.85 0.0541
2022-02-09 2021-12-31 13F WHITE MTNS INS GROUP COM G9618E107 149,502 -611 -0.41 151,580 -5.60 0.0458
2021-11-12 2021-09-30 13F WHITE MTNS INS GROUP COM G9618E107 150,113 6,541 4.56 160,565 -2.58 0.0517
2021-08-12 2021-06-30 13F WHITE MTNS INS GROUP COM G9618E107 143,572 9,274 6.91 164,825 10.08 0.0522
2021-05-14 2021-03-31 13F WHITE MTNS INS GROUP COM G9618E107 134,298 -1,625 -1.20 149,729 10.09 0.0495
2021-03-08 2020-12-31 13F/A-2 WHITE MTNS INS GROUP COM G9618E107 135,923 -2,103 -1.52 136,012 26.50 0.0491
2021-02-11 2020-12-31 13F WHITE MTNS INS GROUP COM G9618E107 135,923 -2,103 136,012 49,120.3050
2020-11-12 2020-09-30 13F WHITE MTNS INS GROUP COM G9618E107 138,026 -836 -0.60 107,521 -12.80 0.0456
2020-08-13 2020-06-30 13F WHITE MTNS INS GROUP COM G9618E107 138,862 -1,599 -1.14 123,304 -3.53 0.0542
2020-05-14 2020-03-31 13F WHITE MTNS INS GROUP COM G9618E107 140,461 1,357 0.98 127,819 -17.63 0.0666
2020-02-14 2019-12-31 13F WHITE MTNS INS GROUP COM G9618E107 139,104 123 0.09 155,173 3.38 0.0566
2019-11-12 2019-09-30 13F WHITE MTNS INS GROUP COM G9618E107 138,981 8,998 6.92 150,098 13.05 0.0583
2019-08-13 2019-06-30 13F WHITE MTNS INS GROUP COM G9618E107 129,983 8,919 7.37 132,772 18.50 0.0516
2019-08-12 2019-03-31 13F/A-2 WHITE MTNS INS GROUP COM G9618E107 121,064 -749 -0.61 112,042 7.24 0.0446
2019-05-10 2019-03-31 13F WHITE MTNS INS GROUP COM G9618E107 121,064 -749 112,042
2019-02-26 2018-12-31 13F/A-1 WHITE MTNS INS GROUP COM G9618E107 121,813 1,552 1.29 104,478 -7.17 0.0473
2019-02-13 2018-12-31 13F WHITE MTNS INS GROUP COM G9618E107 121,813 1,552 104,478
2018-11-13 2018-09-30 13F WHITE MTNS INS GROUP COM G9618E107 120,261 6,751 5.95 112,547 9.37 0.0428
2018-08-10 2018-06-30 13F WHITE MTNS INS GROUP COM G9618E107 113,510 22,927 25.31 102,908 38.12 0.0410
2018-05-11 2018-03-31 13F WHITE MTNS INS GROUP COM G9618E107 90,583 23,995 36.04 74,506 31.44 0.0311
2018-02-12 2017-12-31 13F WHITE MTNS INS GROUP COM G9618E107 66,588 4,769 7.71 56,685 7.00 0.0235
2017-11-13 2017-09-30 13F WHITE MTNS INS GROUP COM G9618E107 61,819 596 0.97 52,978 -0.38 0.0232
2017-08-11 2017-06-30 13F WHITE MTNS INS GROUP COM G9618E107 61,223 2,319 3.94 53,181 2.61 0.0246
2017-05-12 2017-03-31 13F WHITE MTNS INS GROUP COM G9618E107 58,904 3,097 5.55 51,829 11.08 0.0248
2017-02-09 2016-12-31 13F WHITE MTNS INS GROUP COM G9618E107 55,807 5,673 11.32 46,658 12.13 0.0233
2016-11-10 2016-09-30 13F WHITE MTNS INS GROUP COM G9618E107 50,134 4,264 9.30 41,610 7.74 0.0225
2016-08-09 2016-06-30 13F WHITE MTNS INS GROUP COM G9618E107 45,870 324 0.71 38,621 5.65 0.0222
2016-05-13 2016-03-31 13F WHITE MTNS INS GROUP COM G9618E107 45,546 156 0.34 36,556 10.81 0.0219
2016-02-10 2015-12-31 13F WHITE MTNS INS GROUP COM G9618E107 45,390 9,845 27.70 32,991 24.19 0.0206
2015-11-13 2015-09-30 13F WHITE MTNS INS GROUP COM G9618E107 35,545 3,288 10.19 26,565 25.74 0.0174
2015-08-14 2015-06-30 13F WHITE MTNS INS GROUP COM G9618E107 32,257 4,140 14.72 21,127 9.77 0.0129
2015-05-14 2015-03-31 13F WHITE MTNS INS GROUP COM G9618E107 28,117 2,750 10.84 19,246 20.39 0.0122
2015-02-06 2014-12-31 13F WHITE MTNS INS GROUP COM G9618E107 25,367 5,600 28.33 15,986 28.35 0.0105
2014-11-13 2014-09-30 13F WHITE MTNS INS GROUP COM G9618E107 19,767 6,651 50.71 12,455 56.08 0.0088
2014-08-08 2014-06-30 13F WHITE MTNS INS GROUP COM G9618E107 13,116 6,400 95.29 7,980 98.06 0.0055
2014-05-14 2014-03-31 13F WHITE MTNS INS GROUP COM G9618E107 6,716 0 0.00 4,029 -0.52 0.0030
2014-02-12 2013-12-31 13F WHITE MTNS INS GROUP COM G9618E107 6,716 0 0.00 4,050 6.24 0.0032
2013-11-13 2013-09-30 13F WHITE MTNS INS GROUP COM G9618E107 6,716 0 0.00 3,812 -1.27 0.0033
2013-08-15 2013-06-30 13F WHITE MTNS INS GROUP COM G9618E107 6,716 6,716 3,861 0.0036
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.