| $705M | ||
| $310M | ||
| $248M | ||
| $119M | ||
| $57M | ||
| $51M |
Buys | $0 | 0 | 0 |
Sells | $20,838,004 | 3 | 100 |
| Gelston Philip A | director | 0 | $0 | 1 | $338,004 | $-338,004 |
| CAMPBELL REID TARLTON | director | 0 | $0 | 1 | $10.25M | $-10.25M |
| Rountree George Manning | Chief Executive Officer | 0 | $0 | 1 | $10.25M | $-10.25M |
White Mountains Insurance Group, Ltd., established in 1980 with its headquarters in Hamilton, Bermuda, offers a diverse array of insurance and financial services within the United States. The company's operations are divided into five core segments: HG Global/BAM, Ark, NSM, Kudu, and Other Operations. Through its HG Global/BAM segment, the firm provides guarantees for municipal bonds that fund public initiatives such as educational institutions, utilities, and transportation infrastructure, in addition to offering reinsurance coverage. The Ark segment underwrites an extensive range of reinsurance and insurance products, including property, marine and energy, accident and health, casualty, and various specialty lines. NSM operates as a managing general agent and program administrator, delivering specialized property and casualty insurance for distinct sectors like unique transportation needs, real estate, social services organizations, and pet insurance. Kudu focuses on supplying capital solutions to independent asset and wealth management firms, aiding in generational ownership transitions, management buyouts, growth-oriented acquisitions, and ensuring liquidity for legacy partners, while also extending strategic support to its portfolio companies. Lastly, the Other Operations segment provides travel insurance to consumers via both broker networks and direct channels, and manages investment vehicles and separate accounts for external clients within the insurance-linked securities market, covering catastrophe bonds, collateralized reinsurance investments, and industry loss warranties.
Over the last 12 months, insiders at White Mountains Insurance Group, Ltd. have bought $0 and sold $20.84M worth of White Mountains Insurance Group, Ltd. stock.
On average, over the past 5 years, insiders at White Mountains Insurance Group, Ltd. have bought $1.48M and sold $7.57M worth of stock each year.
There was no buying activity among insiders over the last 12 months.
The last purchase of 1,000 shares for transaction amount of $1.48M was made by Hicks Weston M (director) on 2023‑11‑17.
| 2025-12-19 | Sale | Rountree George Manning | Chief Executive Officer | 5,000 0.1966% | $2,050.00 | $10.25M | +5.18% | |
| 2025-12-19 | Sale | CAMPBELL REID TARLTON | director | 5,000 0.1966% | $2,050.00 | $10.25M | +5.18% | |
| 2025-12-16 | Sale | Gelston Philip A | director | 165 0.0065% | $2,048.51 | $338,004 | +4.90% | |
| 2023-11-17 | Hicks Weston M | director | 1,000 0.0391% | $1,480.56 | $1.48M | +18.36% | ||
| 2022-12-22 | Sale | Hildreth Michaela | MD & Chief Accounting Officer | 100 0.0039% | $1,371.84 | $137,184 | +6.01% | |
| 2022-09-20 | Sale | DAVIS MORGAN W | director | 945 0.037% | $1,400.00 | $1.32M | +1.56% | |
| 2022-09-20 | Sale | Carlson Peter M | director | 200 0.0078% | $1,400.00 | $280,000 | +1.56% | |
| 2022-05-31 | Sale | Hildreth Michaela | MD & Chief Accounting Officer | 100 0.004% | $1,270.94 | $127,094 | +9.65% | |
| 2021-02-09 | Sale | DAVIS MORGAN W | director | 1,500 0.0588% | $1,133.28 | $1.7M | -0.01% | |
| 2020-03-24 | DAVIS MORGAN W | director | 1,050 0.0375% | $757.61 | $795,486 | +10.98% | ||
| 2019-12-10 | Sale | SMITH LOWNDES ANDREW | director | 200 0.0077% | $1,105.76 | $221,152 | -18.24% | |
| 2019-08-08 | Sale | SMITH LOWNDES ANDREW | director | 1,000 0.0389% | $1,086.21 | $1.09M | -1.63% | |
| 2019-06-24 | Sale | SEELIG ROBERT LAWRENCE | EVP & General Counsel | 1,000 0.0394% | $1,046.09 | $1.05M | +3.87% | |
| 2019-06-18 | Sale | PALMER JESS BRIAN | Chief Accounting Officer | 431 0.0167% | $1,016.57 | $438,142 | +5.26% | |
| 2019-06-10 | Sale | SMITH LOWNDES ANDREW | director | 500 0.0195% | $1,004.70 | $502,352 | +6.75% | |
| 2019-05-09 | Sale | SEELIG ROBERT LAWRENCE | EVP & General Counsel | 1,083 0.0421% | $977.98 | $1.06M | +9.70% | |
| 2019-04-25 | Sale | DAVIS MORGAN W | director | 554 0.0215% | $928.40 | $514,334 | +15.48% | |
| 2019-04-23 | Sale | DAVIS MORGAN W | director | 696 0.0266% | $910.11 | $633,437 | +15.64% | |
| 2019-04-16 | Sale | DAVIS MORGAN W | director | 354 0.0138% | $912.90 | $323,167 | +17.35% | |
| 2019-04-12 | Sale | DAVIS MORGAN W | director | 585 0.0228% | $916.95 | $536,416 | +17.35% |
| Rountree George Manning | Chief Executive Officer | 13809 0.5576% | $27.68M | 0 | 4 | |
| CAMPBELL REID TARLTON | director | 10440 0.4215% | $20.93M | 0 | 9 | |
| Gelston Philip A | director | 1568 0.0633% | $3.14M | 0 | 1 | |
| BYRNE MARK JAMES | director | 222156 8.9699% | $445.37M | 1 | 0 | +17.4% |
| BERKSHIRE HATHAWAY INC | 10 percent owner | 89279 3.6048% | $178.98M | 0 | 1 | |
| BERKOWITZ BRUCE R | director | 70500 2.8466% | $141.34M | 0 | 1 | |
| KEMP KARL THOMAS | director | 60314 2.4353% | $120.92M | 0 | 9 | |
| GILLESPIE JOHN DAVIES | director | 50000 2.0188% | $100.24M | 0 | 3 | |
| SEELIG ROBERT LAWRENCE | EVP & General Counsel | 11523 0.4653% | $23.1M | 8 | 5 | +18.15% |
| BARRETTE RAYMOND JOSEPH RENE | Chief Executive Officer | 7999 0.323% | $16.04M | 26 | 9 | +30.75% |
| DAVIS MORGAN W | director | 6909 0.279% | $13.85M | 4 | 22 | +37.52% |
| WATERS ALLAN LEWIS | CEO - WTM Re | 6372 0.2573% | $12.77M | 3 | 0 | <0.0001% |
| BYRNE JOHN JOSEPH | director | 4325 0.1746% | $8.67M | 2 | 4 | +18.31% |
| Brouillette Yves | director | 3717 0.1501% | $7.45M | 3 | 2 | +39.72% |
| Hicks Weston M | director | 2306 0.0931% | $4.62M | 1 | 0 | +18.36% |
| Hildreth Michaela | MD & Chief Accounting Officer | 1463 0.0591% | $2.93M | 0 | 2 | |
| PALMER JESS BRIAN | Chief Accounting Officer | 1189 0.048% | $2.38M | 0 | 3 | |
| SMITH LOWNDES ANDREW | director | 1102 0.0445% | $2.21M | 1 | 5 | +4.91% |
| Oberting Kernan V | Managing Director | 836 0.0338% | $1.68M | 0 | 3 | |
| Carlson Peter M | director | 788 0.0318% | $1.58M | 0 | 1 | |
| Tanner David Allen | director | 688 0.0278% | $1.38M | 1 | 0 | +16.12% |
| HOLIDAY EDITH E | director | 200 0.0081% | $400,952.00 | 1 | 0 | +21.47% |
| COCHRAN ROBERT PHILLIPS | director | 0 0% | $0 | 0 | 3 | |
| FASS STEVE ELLIOTT | director | 0 0% | $0 | 0 | 1 | |
| BEAULIEU DENNIS PAUL | Secretary & Treasurer | 0 0% | $0 | 0 | 1 | |
| RITCHIE JAMES JOSEPH | CFO, OneBeacon Insurance Group | 0 0% | $0 | 0 | 1 | |
| Tolman Gary Charles | Pres & CEO - Esurance | 0 0% | $0 | 3 | 1 | <0.0001% |
| Frinquelli Angelo Michael | director | 0 0% | $0 | 8 | 1 | +13.09% |
$153,003,434 | 109 | 11.98% | $10.91B | |
$25,342,934 | 101 | -6.52% | $1.43B | |
$4,309,045 | 97 | 6.81% | $2.01B | |
$9,113,360 | 92 | 7.43% | $4.8B | |
$10,864,380 | 68 | 8.54% | $22.72B | |
White Mountains Insurance Group, Ltd. (WTM) | $33,778,786 | 61 | 22.18% | $4.97B |
$620,622,916 | 56 | 15.87% | $7.2B | |
$8,525,067 | 50 | 4.60% | $2.01B | |
$32,326,727 | 49 | 20.05% | $5.6B | |
$774,000,000 | 39 | 26.65% | $11.89B | |
$7,343,423 | 25 | 6.77% | $6.73B | |
$112,415,853 | 24 | 11.03% | $22.01B | |
$3,919,230 | 23 | 9.61% | $5.4B | |
$3,522,142 | 11 | 53.32% | $6.99B | |
$622,842 | 8 | 22.22% | $2.88B | |
$640,644 | 6 | 3.88% | $1.92B | |
$1,477,495 | 5 | 55.81% | $4.12B | |
$62,561,064 | 5 | 12.40% | $3.65B | |
$39,552 | 2 | 23.44% | $1.9B |
| Increased Positions | 159 | +39.45% | 112,304 | +4.75% |
| Decreased Positions | 167 | -41.44% | 224,018 | -9.48% |
| New Positions | 52 | New | 48,776 | New |
| Sold Out Positions | 36 | Sold Out | 18,705 | Sold Out |
| Total Postitions | 395 | -1.99% | 2M | -4.73% |
| Vanguard Group Inc | $504,357.00 | 12.35% | 247,004 | -2,166 | -0.87% | 2025-09-30 |
| Dimensional Fund Advisors Lp | $321,021.00 | 7.86% | 157,217 | +1,464 | +0.94% | 2025-09-30 |
| Morgan Stanley | $283,542.00 | 6.94% | 138,862 | -26,202 | -15.87% | 2025-09-30 |
| Neuberger Berman Group Llc | $234,849.00 | 5.75% | 115,015 | +31,316 | +37.41% | 2025-09-30 |
| Blackrock, Inc. | $229,875.00 | 5.63% | 112,579 | -579 | -0.51% | 2025-09-30 |
| River Road Asset Management, Llc | $223,768.00 | 5.48% | 109,588 | -304 | -0.28% | 2025-09-30 |
| Fuller & Thaler Asset Management, Inc. | $220,711.00 | 5.41% | 108,091 | +7,107 | +7.04% | 2025-09-30 |
| Cooke & Bieler Lp | $220,221.00 | 5.39% | 107,851 | +31,070 | +40.47% | 2025-09-30 |
| Fiduciary Management Inc /Wi/ | $192,721.00 | 4.72% | 94,383 | +22,905 | +32.05% | 2025-09-30 |
| Boston Partners | $172,428.00 | 4.22% | 84,445 | -4,949 | -5.54% | 2025-09-30 |