White Mountains Insurance Group (WTM)
White Mountains Insurance Group on one page: short interest, daily short volume, fails to deliver, large holders, 13F holders, earnings dates and insider trades. Listed on NYSE, classified by the SEC as fire, marine & casualty insurance.
147K
Short interest
settlement 2026-10-15
7.3
Days to cover
-0.1 days vs prior
75.3%
Short share of volume
2026-11-02
137
Fails to deliver
settlement 2026-10-13
Thu 5 Nov
Next earnings
estimated date
$0
Insider flow, 90 days
0 buys, 0 sells
As of 2026-11-02.
Short interest
FINRA, twice a month. The newest 48 settlements in the table, 48 in the chart. JSONAs of 15 October 2026, short interest in WTM is 146,873 shares, up 11,466 shares over the last month. Over the last 48 readings it ranged from 33,989 shares (29 November 2024) to 146,873 shares (15 October 2026). The latest reading sits at the top of that range. At the reported average volume of 20K shares a day that is 7.3 days to cover.
Embed this chart.The embed keeps its attribution line.
<iframe src="https://xoomar.com/embed/stocks/wtm" width="100%" height="440" style="border:0;max-width:100%" loading="lazy" title="XOOMAR chart"></iframe>
| Settlement | Shares short | Change | Avg daily volume | Days to cover |
|---|---|---|---|---|
| 2026-10-15 | 146,873 | +5.2% | 20,114 | 7.30 |
| 2026-09-30 | 139,645 | +3.1% | 18,801 | 7.43 |
| 2026-09-15 | 135,407 | +2.8% | 21,956 | 6.17 |
| 2026-08-31 | 131,685 | -3.4% | 20,341 | 6.47 |
| 2026-08-14 | 136,316 | -0.5% | 24,045 | 5.67 |
| 2026-07-31 | 136,979 | -1.0% | 16,053 | 8.53 |
| 2026-07-15 | 138,306 | +10.9% | 18,729 | 7.38 |
| 2026-06-30 | 124,761 | +4.6% | 18,170 | 6.87 |
| 2026-06-15 | 119,240 | +31.1% | 26,358 | 4.52 |
| 2026-05-29 | 90,960 | +3.4% | 22,008 | 4.13 |
| 2026-05-15 | 87,955 | +12.7% | 23,809 | 3.69 |
| 2026-04-30 | 78,013 | +8.8% | 13,172 | 5.92 |
| 2026-04-15 | 71,686 | -12.8% | 18,673 | 3.84 |
| 2026-03-31 | 82,241 | -6.1% | 17,934 | 4.59 |
| 2026-03-13 | 87,581 | +16.6% | 21,208 | 4.13 |
| 2026-02-27 | 75,110 | +8.2% | 16,297 | 4.61 |
| 2026-02-13 | 69,433 | -14.7% | 17,824 | 3.90 |
| 2026-01-30 | 81,413 | +12.9% | 15,900 | 5.12 |
| 2026-01-15 | 72,099 | +11.3% | 18,663 | 3.86 |
| 2025-12-31 | 64,771 | -25.6% | 18,242 | 3.55 |
| 2025-12-15 | 87,076 | -20.7% | 21,955 | 3.97 |
| 2025-11-28 | 109,757 | +15.1% | 18,913 | 5.80 |
| 2025-11-14 | 95,355 | -11.6% | 22,756 | 4.19 |
| 2025-10-31 | 107,804 | +14.0% | 25,744 | 4.19 |
| 2025-10-15 | 94,581 | +16.8% | 37,911 | 2.49 |
| 2025-09-30 | 80,962 | +23.6% | 35,139 | 2.30 |
| 2025-09-15 | 65,515 | +1.6% | 35,623 | 1.84 |
| 2025-08-29 | 64,506 | -9.1% | 26,594 | 2.43 |
| 2025-08-15 | 70,931 | +23.7% | 29,744 | 2.38 |
| 2025-07-31 | 57,332 | -5.4% | 18,894 | 3.03 |
| 2025-07-15 | 60,625 | +3.7% | 31,742 | 1.91 |
| 2025-06-30 | 58,478 | +8.7% | 22,264 | 2.63 |
| 2025-06-13 | 53,796 | +0.9% | 23,262 | 2.31 |
| 2025-05-30 | 53,327 | -2.9% | 19,708 | 2.71 |
| 2025-05-15 | 54,912 | +2.9% | 11,775 | 4.66 |
| 2025-04-30 | 53,364 | +0.1% | 13,079 | 4.08 |
| 2025-04-15 | 53,283 | -0.8% | 23,867 | 2.23 |
| 2025-03-31 | 53,715 | -22.1% | 14,763 | 3.64 |
| 2025-03-14 | 68,965 | +17.0% | 18,175 | 3.79 |
| 2025-02-28 | 58,923 | +13.6% | 12,497 | 4.71 |
| 2025-02-14 | 51,859 | -1.1% | 12,589 | 4.12 |
| 2025-01-31 | 52,451 | +24.9% | 15,220 | 3.45 |
| 2025-01-15 | 41,993 | -10.3% | 15,288 | 2.75 |
| 2024-12-31 | 46,802 | +30.1% | 13,981 | 3.35 |
| 2024-12-13 | 35,969 | +5.8% | 11,591 | 3.10 |
| 2024-11-29 | 33,989 | -13.8% | 8,097 | 4.20 |
| 2024-11-15 | 39,408 | -9.0% | 15,489 | 2.54 |
| 2024-10-31 | 43,312 | +3.7% | 11,613 | 3.73 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 2 November 2026, the short share of WTM volume is 75.3%, down 10.2 points over the last five sessions. Over the last 30 readings it ranged from 50.6% (30 October 2026) to 85.5% (26 October 2026). The latest reading is 3.7 points above the 30-session average of 71.6%, on 10K shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-11-02 | 8K | 10K | 75.3% | 3 |
| 2026-10-30 | 4K | 9K | 50.6% | 3 |
| 2026-10-29 | 7K | 10K | 66.8% | 2 |
| 2026-10-28 | 8K | 9K | 80.6% | 0 |
| 2026-10-27 | 6K | 8K | 75.6% | 0 |
| 2026-10-26 | 7K | 8K | 85.5% | 0 |
| 2026-10-23 | 6K | 8K | 77.7% | 0 |
| 2026-10-22 | 5K | 8K | 64.7% | 0 |
| 2026-10-21 | 9K | 13K | 66.9% | 3 |
| 2026-10-20 | 7K | 9K | 75.2% | 1 |
| 2026-10-19 | 5K | 7K | 77.8% | 0 |
| 2026-10-16 | 8K | 10K | 75.4% | 0 |
| 2026-10-15 | 9K | 12K | 77.2% | 0 |
| 2026-10-14 | 5K | 6K | 78.9% | 100 |
| 2026-10-13 | 5K | 7K | 67.7% | 5 |
| 2026-10-12 | 9K | 11K | 80.1% | 20 |
| 2026-10-09 | 7K | 9K | 75.2% | 1 |
| 2026-10-08 | 6K | 8K | 75.9% | 0 |
| 2026-10-07 | 6K | 8K | 74.0% | 0 |
| 2026-10-06 | 5K | 6K | 73.7% | 0 |
| 2026-10-05 | 4K | 6K | 63.8% | 0 |
| 2026-10-02 | 4K | 6K | 66.2% | 0 |
| 2026-10-01 | 4K | 7K | 61.9% | 0 |
| 2026-09-30 | 3K | 5K | 68.6% | 0 |
| 2026-09-29 | 4K | 6K | 61.8% | 0 |
| 2026-09-28 | 4K | 7K | 64.9% | 0 |
| 2026-09-25 | 2K | 3K | 70.8% | 0 |
| 2026-09-24 | 3K | 4K | 74.2% | 0 |
| 2026-09-23 | 4K | 6K | 65.0% | 0 |
| 2026-09-22 | 5K | 6K | 76.2% | 0 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 13 October 2026, the fails-to-deliver balance in WTM is 137 shares, up 127 shares over the last settlement date. Over the last 30 readings it ranged from 1 share (18 February 2026) to 2,778 shares (29 December 2025). The latest reading sits at the bottom of that range.
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-10-13 | 137 | $2086.76 | $286K |
| 2026-10-09 | 10 | $2059.77 | $21K |
| 2026-07-23 | 6 | $2182.32 | $13K |
| 2026-07-21 | 11 | $2211.22 | $24K |
| 2026-07-01 | 2 | $2073.39 | $4K |
| 2026-06-30 | 577 | $2090.94 | $1.2M |
| 2026-06-29 | 48 | $2096.56 | $101K |
| 2026-06-04 | 2 | $2034.02 | $4K |
| 2026-06-03 | 271 | $2050.81 | $556K |
| 2026-05-26 | 1 | $2146.85 | $2K |
| 2026-02-18 | 1 | $2230.83 | $2K |
| 2026-02-03 | 304 | $2056.36 | $625K |
| 2026-02-02 | 394 | $2044.93 | $806K |
| 2026-01-29 | 17 | $2039.19 | $35K |
| 2026-01-28 | 112 | $2052.44 | $230K |
| 2026-01-27 | 4 | $2076.93 | $8K |
| 2026-01-23 | 17 | $2071.97 | $35K |
| 2026-01-20 | 50 | $2056.36 | $103K |
| 2026-01-08 | 32 | $2059.54 | $66K |
| 2026-01-06 | 23 | $2062.86 | $47K |
| 2026-01-05 | 50 | $2041.90 | $102K |
| 2026-01-02 | 29 | $2078.03 | $60K |
| 2025-12-29 | 2,778 | $2062.34 | $5.7M |
| 2025-12-16 | 116 | $2068.17 | $240K |
| 2025-12-10 | 96 | $2018.75 | $194K |
| 2025-12-08 | 41 | $2034.79 | $83K |
| 2025-11-21 | 27 | $1881.61 | $51K |
| 2025-11-20 | 71 | $1889.30 | $134K |
| 2025-11-07 | 119 | $1892.02 | $225K |
| 2025-10-30 | 34 | $1897.99 | $65K |
Insider trades
SEC Form 4, newest first. JSONNo open-market insider trades were reported for WTM in the last 90 days. The most recent filings are listed below. Latest filing: Tanner David Allen (Director) on 2026-08-31.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-08-31 | Tanner David Allen | Director | Gift | 2 | $0.00 | $0 | 2K |
| 2026-08-26 | Klar Stephen | Director | Grant | 113 | $0.00 | $0 | 113 |
| 2026-05-21 | Tanner David Allen | Director | Grant | 135 | $0.00 | $0 | 2K |
| 2026-05-21 | SHANK SUZANNE F. | Director | Grant | 135 | $0.00 | $0 | 1K |
| 2026-05-21 | Hicks Weston M | Director | Grant | 190 | $0.00 | $0 | 3K |
| 2026-05-21 | Gelston Philip A | Director | Grant | 135 | $0.00 | $0 | 2K |
| 2026-05-21 | Dillon Margaret | Director | Grant | 135 | $0.00 | $0 | 1K |
| 2026-05-21 | Chu John | Director | Grant | 135 | $0.00 | $0 | 335 |
| 2026-05-21 | Carlson Peter M | Director | Grant | 135 | $0.00 | $0 | 852 |
| 2026-05-21 | CHOKSI MARY C | Director | Grant | 135 | $0.00 | $0 | 2K |
| 2026-05-21 | CAMPBELL REID TARLTON | Director | Grant | 135 | $0.00 | $0 | 11K |
| 2026-03-19 | SEELIG ROBERT LAWRENCE | EVP & General Counsel | Gift | 50 | $0.00 | $0 | 18K |
| 2026-03-04 | Tanner David Allen | Director | Gift | 225 | $0.00 | $0 | 2K |
| 2026-02-25 | SEELIG ROBERT LAWRENCE | EVP & General Counsel | Grant | 775 | $0.00 | $0 | 3K |
| 2026-02-25 | Papamichael Michael A | Chief Financial Officer | Grant | 500 | $0.00 | $0 | 1K |
| 2026-02-25 | Hildreth Michaela | MD & Chief Accounting Officer | Grant | 600 | $0.00 | $0 | 2K |
| 2026-02-25 | Harrison Giles E | President | Grant | 775 | $0.00 | $0 | 3K |
| 2026-02-25 | Caffrey Liam P | Chief Executive Officer | Grant | 2K | $0.00 | $0 | 4K |
| 2026-01-01 | SEELIG ROBERT LAWRENCE | EVP & General Counsel | Tax withholding | 398 | $2078.03 | $827K | 18K |
| 2026-01-01 | Papamichael Michael A | Chief Financial Officer | Tax withholding | 131 | $2078.03 | $272K | 772 |
| 2026-01-01 | Caffrey Liam P | Chief Executive Officer | Tax withholding | 425 | $2078.03 | $883K | 2K |
| 2026-01-01 | Hildreth Michaela | MD & Chief Accounting Officer | Tax withholding | 274 | $2078.03 | $569K | 2K |
| 2025-12-23 | Hildreth Michaela | MD & Chief Accounting Officer | Gift | 60 | $0.00 | $0 | 2K |
| 2025-12-19 | CAMPBELL REID TARLTON | Director | Sell | 5K | $2050.00 | $10.3M | 10K |
| 2025-12-19 | Rountree George Manning | Chief Executive Officer | Sell | 5K | $2050.00 | $10.3M | 14K |
| 2025-12-19 | CAMPBELL REID TARLTON | Director | Sell | 5K | $0.00 | $0 | 10K |
| 2025-12-16 | Gelston Philip A | Director | Sell | 165 | $2048.51 | $338K | 2K |
| 2025-11-25 | CAMPBELL REID TARLTON | Director | Gift | 50 | $0.00 | $0 | 15K |
| 2025-11-10 | Tanner David Allen | Director | Gift | 4 | $0.00 | $0 | 2K |
| 2025-05-22 | CAMPBELL REID TARLTON | Director | Grant | 150 | $0.00 | $0 | 15K |
| 2025-05-22 | Carlson Peter M | Director | Grant | 150 | $0.00 | $0 | 717 |
| 2025-05-22 | CHOKSI MARY C | Director | Grant | 150 | $0.00 | $0 | 2K |
| 2025-05-22 | Dillon Margaret | Director | Grant | 150 | $0.00 | $0 | 945 |
| 2025-05-22 | Gelston Philip A | Director | Grant | 150 | $0.00 | $0 | 2K |
| 2025-05-22 | Hicks Weston M | Director | Grant | 210 | $0.00 | $0 | 3K |
| 2025-05-22 | Tanner David Allen | Director | Grant | 150 | $0.00 | $0 | 2K |
| 2025-05-22 | Yi Steven | Director | Grant | 150 | $0.00 | $0 | 525 |
| 2025-05-22 | SHANK SUZANNE F. | Director | Grant | 150 | $0.00 | $0 | 871 |
| 2025-02-26 | Hildreth Michaela | MD & Chief Accounting Officer | Grant | 625 | $0.00 | $0 | 2K |
| 2025-02-26 | SEELIG ROBERT LAWRENCE | EVP & General Counsel | Grant | 825 | $0.00 | $0 | 3K |
| 2025-02-26 | Harrison Giles E | EVP & Chief Strategy Officer | Grant | 900 | $0.00 | $0 | 2K |
| 2025-02-26 | Caffrey Liam P | EVP& Chief Financial Officer | Grant | 1K | $0.00 | $0 | 3K |
| 2025-02-26 | Rountree George Manning | Chief Executive Officer | Grant | 2K | $0.00 | $0 | 5K |
| 2025-01-01 | Hildreth Michaela | MD & Chief Accounting Officer | Tax withholding | 323 | $1945.06 | $628K | 2K |
| 2025-01-01 | SEELIG ROBERT LAWRENCE | EVP & General Counsel | Tax withholding | 496 | $1945.06 | $965K | 17K |
| 2025-01-01 | Caffrey Liam P | President & CFO | Tax withholding | 420 | $1945.06 | $817K | 830 |
| 2025-01-01 | Rountree George Manning | Chief Executive Officer | Tax withholding | 1K | $1945.06 | $2.1M | 19K |
| 2024-11-29 | Hildreth Michaela | MD & Chief Accounting Officer | Gift | 75 | $0.00 | $0 | 2K |
| 2024-06-10 | Harrison Giles E | EVP & Chief Strategy Officer | Grant | 1K | $0.00 | $0 | 1K |
| 2024-05-23 | Hicks Weston M | Director | Grant | 230 | $0.00 | $0 | 3K |
| 2024-05-23 | CAMPBELL REID TARLTON | Director | Grant | 165 | $0.00 | $0 | 15K |
| 2024-05-23 | Carlson Peter M | Director | Grant | 165 | $0.00 | $0 | 1K |
| 2024-05-23 | CHOKSI MARY C | Director | Grant | 165 | $0.00 | $0 | 2K |
| 2024-05-23 | Dillon Margaret | Director | Grant | 165 | $0.00 | $0 | 795 |
| 2024-05-23 | Gelston Philip A | Director | Grant | 165 | $0.00 | $0 | 2K |
| 2024-05-23 | SHANK SUZANNE F. | Director | Grant | 165 | $0.00 | $0 | 721 |
| 2024-05-23 | Tanner David Allen | Director | Grant | 165 | $0.00 | $0 | 2K |
| 2024-05-23 | Yi Steven | Director | Grant | 165 | $0.00 | $0 | 375 |
| 2024-03-21 | CAMPBELL REID TARLTON | Director | Gift | 55 | $0.00 | $0 | 15K |
| 2024-02-22 | CAMPBELL REID TARLTON | Director | Grant | 45 | $0.00 | $0 | 15K |
| 2024-02-22 | Hildreth Michaela | MD & Chief Accounting Officer | Grant | 600 | $0.00 | $0 | 2K |
| 2024-02-22 | SEELIG ROBERT LAWRENCE | EVP & General Counsel | Grant | 900 | $0.00 | $0 | 3K |
| 2024-02-22 | Caffrey Liam P | EVP& Chief Financial Officer | Grant | 1K | $0.00 | $0 | 4K |
| 2024-02-22 | Rountree George Manning | Chief Executive Officer | Grant | 2K | $0.00 | $0 | 7K |
| 2024-01-01 | Hildreth Michaela | MD & Chief Accounting Officer | Tax withholding | 261 | $1505.01 | $393K | 2K |
| 2024-01-01 | SEELIG ROBERT LAWRENCE | EVP & General Counsel | Tax withholding | 399 | $1505.01 | $600K | 17K |
| 2024-01-01 | CAMPBELL REID TARLTON | President | Tax withholding | 710 | $1505.01 | $1.1M | 15K |
| 2024-01-01 | Rountree George Manning | Chief Executive Officer | Tax withholding | 1K | $1505.01 | $1.6M | 17K |
| 2023-12-01 | Hildreth Michaela | MD & Chief Accounting Officer | Gift | 100 | $0.00 | $0 | 2K |
| 2023-11-17 | Hicks Weston M | Director | Buy | 579 | $1479.88 | $857K | 2K |
| 2023-11-17 | Hicks Weston M | Director | Buy | 52 | $1476.15 | $77K | 1K |
| 2023-11-17 | Hicks Weston M | Director | Buy | 120 | $1476.74 | $177K | 1K |
| 2023-11-17 | Hicks Weston M | Director | Buy | 238 | $1484.96 | $353K | 2K |
| 2023-11-17 | Hicks Weston M | Director | Buy | 11 | $1483.43 | $16K | 2K |
| 2023-05-25 | Yi Steven | Director | Grant | 180 | $0.00 | $0 | 210 |
| 2023-05-25 | Hicks Weston M | Director | Grant | 250 | $0.00 | $0 | 1K |
| 2023-05-25 | CHOKSI MARY C | Director | Grant | 180 | $0.00 | $0 | 2K |
| 2023-05-25 | Gelston Philip A | Director | Grant | 180 | $0.00 | $0 | 1K |
| 2023-05-25 | SHANK SUZANNE F. | Director | Grant | 180 | $0.00 | $0 | 556 |
| 2023-05-25 | Tanner David Allen | Director | Grant | 180 | $0.00 | $0 | 2K |
| 2023-05-25 | Dillon Margaret | Director | Grant | 180 | $0.00 | $0 | 630 |
| 2023-05-25 | Carlson Peter M | Director | Grant | 180 | $0.00 | $0 | 968 |
| 2023-02-22 | Hicks Weston M | Director | Grant | 56 | $0.00 | $0 | 1K |
| 2023-02-22 | Hildreth Michaela | MD & Chief Accounting Officer | Grant | 600 | $0.00 | $0 | 2K |
| 2023-02-22 | SEELIG ROBERT LAWRENCE | EVP & General Counsel | Grant | 1K | $0.00 | $0 | 3K |
| 2023-02-22 | Caffrey Liam P | EVP& Chief Financial Officer | Grant | 1K | $0.00 | $0 | 3K |
| 2023-02-22 | Rountree George Manning | Chief Executive Officer | Grant | 2K | $0.00 | $0 | 7K |
| 2023-01-01 | Hildreth Michaela | MD & Chief Accounting Officer | Tax withholding | 176 | $1414.33 | $249K | 2K |
| 2023-01-01 | SEELIG ROBERT LAWRENCE | EVP & General Counsel | Tax withholding | 359 | $1414.33 | $508K | 16K |
| 2023-01-01 | CAMPBELL REID TARLTON | President | Tax withholding | 710 | $1414.33 | $1.0M | 14K |
| 2023-01-01 | Rountree George Manning | Chief Executive Officer | Tax withholding | 1K | $1414.33 | $1.5M | 16K |
| 2022-12-28 | Hildreth Michaela | MD & Chief Accounting Officer | Gift | 53 | $0.00 | $0 | 1K |
| 2022-12-28 | DAVIS MORGAN W | Director | Gift | 200 | $0.00 | $0 | 7K |
| 2022-12-22 | Hildreth Michaela | MD & Chief Accounting Officer | Sell | 100 | $1371.84 | $137K | 1K |
| 2022-09-20 | DAVIS MORGAN W | Director | Sell | 945 | $1400.00 | $1.3M | 7K |
| 2022-09-20 | Carlson Peter M | Director | Sell | 200 | $1400.00 | $280K | 788 |
| 2022-06-01 | CAMPBELL REID TARLTON | President | Gift | 100 | $0.00 | $0 | 13K |
| 2022-05-31 | Hildreth Michaela | MD & Chief Accounting Officer | Sell | 100 | $1270.94 | $127K | 2K |
| 2022-05-26 | SHANK SUZANNE F. | Director | Grant | 225 | $0.00 | $0 | 376 |
| 2022-05-26 | Tanner David Allen | Director | Grant | 225 | $0.00 | $0 | 2K |
Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are rarer.
Large holders (13D and 13G)
One row per reporting person with its latest filing, newest first. JSON1 holder reports 5% or more of WTM in its latest filing, on Schedule 13G (passive). The holder is Vanguard Capital Management at 5.2% of the class (127,993 shares), filed 2026-04-30 for an event on 2026-03-31.
| Filed | Form | Holder | Shares | Of class | Event |
|---|---|---|---|---|---|
| 2026-05-07 | 13G/Ano. 1 | Neuberger Berman Group LLCparent holding company | 122K | 4.9% | 2026-04-30 |
| 2026-05-07 | 13G/Ano. 1 | Neuberger Berman Investment Advisers LLCinvestment adviser | 118K | 4.8% | 2026-04-30 |
| 2026-04-30 | 13G | Vanguard Capital Managementinvestment adviser | 128K | 5.2% | 2026-03-31 |
| 2026-03-27 | 13G/Ano. 11 | The Vanguard Groupinvestment adviser | 0 | 0.0% | 2026-03-13 |
| 2026-02-12 | 13G/Ano. 7 | Morgan Stanleyparent holding company, corporation | 77K | 3.0% | 2025-12-31 |
13F holders
Tracked managers holding WTM at their latest 13F. JSON4 of the 30 tracked managers held WTM at their latest 13F, $40.1M in total at quarter-end prices. Citadel Advisors is the largest at $14.8M (0.0% of its portfolio) as of 2026-06-30. Over the prior quarter 1 added shares and 3 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| Citadel Advisors | 2026-06-30 | 7K | $14.8M | 0.00% | +5K |
| D. E. Shaw & Co. | 2026-06-30 | 7K | $13.7M | 0.01% | -2K |
| AQR Capital Management | 2026-06-30 | 5K | $11.3M | 0.00% | -2K |
| Millennium Management | 2026-06-30 | 143 | $296K | 0.00% | -244 |
Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.
What this page is
White Mountains Insurance Group in the regulatory record
Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page puts those series for one ticker on one URL, with planned sales, large holders, 13F holders and financials beside them, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.
Each section has its own history table, a one-line summary of the latest figures and its own JSON and CSV links, and says when its source last updated.
This page follows White Mountains Insurance Group (WTM), SEC CIK 776867, listed on NYSE, classified by the SEC as fire, marine & casualty insurance. The cross-market tables live on the short interest and insider transactions hubs.
Source and updates
- Short interest
- FINRA consolidated short interestSource: FINRA.Twice a month, about eight business days after settlement. Latest 2026-10-15.JSON and CSV
- Daily short volume
- FINRA Reg SHO daily filesSource: FINRA.Every trading day, the morning after FINRA posts it. Latest 2026-11-02.JSON and CSV
- Fails to deliver
- SEC fails-to-deliver dataSource: SEC.Twice a month, a few weeks after the half month ends. Latest 2026-10-13.JSON and CSV
- Large holders
- SEC EDGAR Schedule 13D and 13GSource: SEC.New filings appear shortly after the SEC posts them. A 13D is due within five business days of crossing 5%; a 13G follows the passive schedule. Latest 2026-05-07.JSON and CSV
- 13F holders
- SEC EDGAR Form 13F-HRSource: SEC.Quarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
- Earnings dates
- SEC EDGAR 8-K filings (Item 2.02)Source: SEC.Twice a day. Reported dates come from the company's 8-K filings; the next date is marked as an estimate until the 8-K arrives. Latest 2026-08-06.JSON and CSV
- Insider trades
- SEC EDGAR Form 4Source: SEC.New filings appear shortly after the SEC posts them; they're due two business days after the trade. Latest 2026-08-31.JSON and CSV
- Company record
- EDGAR filing index for CIK 776867Ticker, name and exchange from the SEC's company list, refreshed weekly.
- Rate limits
- 10 requests a minute without a key, 30 with a free key from a free account.
How to read it
- Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
- Insider buys next to a large short position are rare and stand out; insider sells next to one are common and mean little.
- Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.
Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.
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Datasets
Frequently Asked Questions
How much of WTM is sold short?
146,873 shares were held short at the 2026-10-15 settlement, 7.3 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.
What is WTM's daily short volume?
On 2026-11-02, 7,832 of the 10,403 WTM shares reported to FINRA were sold short, 75.3% of the day's reported volume. Short volume is a flow for one day, not a position.
Does WTM have fails to deliver?
The SEC's latest file shows 137 WTM shares failed to deliver at settlement 2026-10-13. Fails are reported per settlement date and published twice a month with a lag.
Are WTM insiders buying or selling?
No open-market insider trades were reported for WTM in the last 90 days. The most recent filings are listed below. Latest filing: Tanner David Allen (Director) on 2026-08-31.
Who owns 5% or more of WTM?
1 holder reports 5% or more of WTM in its latest filing, on Schedule 13G (passive). The holder is Vanguard Capital Management at 5.2% of the class (127,993 shares), filed 2026-04-30 for an event on 2026-03-31.
Which tracked 13F managers own WTM?
4 of the 30 tracked 13F managers held WTM shares at their latest filing, $40.1M in all. The largest: Ken Griffin's Citadel Advisors (7K shares, $14.8M), D. E. Shaw & Co. (7K shares, $13.7M), Cliff Asness's AQR Capital Management (5K shares, $11.3M), Izzy Englander's Millennium Management (143 shares, $296K).
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.