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United States Insurance

White Mountains Insurance Group Ltd (WTM)

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The most recent insider trading activity occurred on December 19, 2025, with a significant sell transaction by the Chief Executive Officer. Prior to this, another sell transaction was recorded on December 16, 2025. Earlier buy transactions by another insider date back to November 17, 2023.
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Ticker: WTM Exchange: NYS
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• Purchase • Sale • Planned purchase • Planned sale Net purchase Net sale Activity signal Earnings
Top insiders
Trades
Rountree George Manning
Chief Executive Officer
1 sale — total 10,250,000 USD
Sale 19 Dec 2025
Value US$1,163,453.74 | Price 295.86 | Shares 64,663
Sale 16 Dec 2025
Value US$3,864,971.98 | Price 15.30 | Shares 90,373
Buy 17 Nov 2023
Value US$353,420.48 | Price 1,484.96 | Shares 238
Buy 17 Nov 2023
Value US$16,317.73 | Price 1,483.43 | Shares 11
Buy 17 Nov 2023
Value US$856,850.52 | Price 1,479.88 | Shares 579
Buy 17 Nov 2023
Value US$177,208.80 | Price 1,476.74 | Shares 120
Buy 17 Nov 2023
Value US$76,759.80 | Price 1,476.15 | Shares 52
Sale 22 Dec 2022
Value US$137,184.00 | Price 1,371.84 | Shares 100
Sale 20 Sep 2022
Value US$280,000.00 | Price 1,400.00 | Shares 200
Sale 20 Sep 2022
Value US$1,323,000.00 | Price 1,400.00 | Shares 945
Sale 31 May 2022
Value US$127,094.00 | Price 1,270.94 | Shares 100
Sale 9 Feb 2021
Value US$376,429.00 | Price 1,117.00 | Shares 337
Sale 9 Feb 2021
Value US$1,323,494.00 | Price 1,138.00 | Shares 1,163
Buy 24 Mar 2020
Value US$39,250.00 | Price 785.00 | Shares 50
Buy 24 Mar 2020
Value US$477,386.00 | Price 782.60 | Shares 610
Buy 24 Mar 2020
Value US$278,850.00 | Price 715.00 | Shares 390
Sale 10 Dec 2019
Value US$221,152.00 | Price 1,105.76 | Shares 200
Sale 8 Aug 2019
Value US$782,652.71 | Price 1,085.51 | Shares 721
Sale 8 Aug 2019
Value US$303,554.79 | Price 1,088.01 | Shares 279
Sale 24 Jun 2019
Value US$10,523.10 | Price 1,052.31 | Shares 10
Sale 24 Jun 2019
Value US$108,047.00 | Price 1,049.00 | Shares 103
Sale 24 Jun 2019
Value US$73,369.80 | Price 1,048.14 | Shares 70
Sale 24 Jun 2019
Value US$687,833.01 | Price 1,046.93 | Shares 657
Sale 24 Jun 2019
Value US$166,320.00 | Price 1,039.50 | Shares 160
Sale 18 Jun 2019
Value US$438,141.67 | Price 1,016.57 | Shares 431
Sale 10 Jun 2019
Value US$301,272.00 | Price 1,004.24 | Shares 300
Sale 10 Jun 2019
Value US$201,080.00 | Price 1,005.40 | Shares 200
Sale 9 May 2019
Value US$58,500.00 | Price 975.00 | Shares 60
Sale 9 May 2019
Value US$840,512.40 | Price 977.34 | Shares 860
Sale 9 May 2019
Value US$78,369.60 | Price 979.62 | Shares 80
Sale 9 May 2019
Value US$81,771.60 | Price 985.20 | Shares 83
Sale 25 Apr 2019
Value US$514,333.60 | Price 928.40 | Shares 554
Planned sale 23 Apr 2019
Value US$633,436.56 | Price 910.11 | Shares 696
Planned sale 16 Apr 2019
Value US$323,166.60 | Price 912.90 | Shares 354
Sale 12 Apr 2019
Value US$536,415.75 | Price 916.95 | Shares 585
Planned sale 10 Apr 2019
Value US$376,975.88 | Price 914.99 | Shares 412
Planned sale 4 Apr 2019
Value US$840,521.50 | Price 923.65 | Shares 910
Sale 2 Apr 2019
Value US$334,850.00 | Price 925.00 | Shares 362
Planned sale 1 Apr 2019
Value US$787,375.80 | Price 924.15 | Shares 852
Planned sale 27 Mar 2019
Value US$554,518.66 | Price 922.66 | Shares 601
Buy 26 Mar 2019
Value US$454,637.70 | Price 918.46 | Shares 495
Buy 26 Mar 2019
Value US$4,585.25 | Price 917.05 | Shares 5
Sale 26 Mar 2019
Value US$366,680.00 | Price 916.70 | Shares 400
Planned sale 22 Mar 2019
Value US$648,026.00 | Price 914.00 | Shares 709
Planned sale 19 Mar 2019
Value US$882,650.34 | Price 925.21 | Shares 954
Planned sale 13 Mar 2019
Value US$572,910.14 | Price 907.94 | Shares 631
Sale 12 Mar 2019
Value US$382,952.56 | Price 903.19 | Shares 424
Sale 12 Mar 2019
Value US$255,874.45 | Price 904.15 | Shares 283
Sale 12 Mar 2019
Value US$362,000.00 | Price 905.00 | Shares 400
Sale 12 Mar 2019
Value US$146,188.00 | Price 908.00 | Shares 161
Sale 11 Mar 2019
Value US$816,732.00 | Price 907.48 | Shares 900
Sale 11 Mar 2019
Value US$522,368.70 | Price 910.05 | Shares 574
Sale 11 Mar 2019
Value US$12,754.84 | Price 911.06 | Shares 14
Sale 11 Mar 2019
Value US$10,948.80 | Price 912.40 | Shares 12
Sale 11 Mar 2019
Value US$55,815.00 | Price 915.00 | Shares 61
Sale 11 Mar 2019
Value US$175,906.56 | Price 916.18 | Shares 192
Sale 11 Mar 2019
Value US$193,487.00 | Price 917.00 | Shares 211
Sale 11 Mar 2019
Value US$117,582.08 | Price 918.61 | Shares 128
Sale 6 Mar 2019
Value US$958,490.00 | Price 958.49 | Shares 1,000
Sale 5 Mar 2019
Value US$803,683.08 | Price 949.98 | Shares 846
Sale 5 Mar 2019
Value US$8,550.99 | Price 950.11 | Shares 9
Sale 5 Mar 2019
Value US$47,512.50 | Price 950.25 | Shares 50
Sale 5 Mar 2019
Value US$77,982.00 | Price 951.00 | Shares 82
Sale 5 Mar 2019
Value US$12,364.30 | Price 951.10 | Shares 13
Sale 20 Dec 2018
Value US$84,539.00 | Price 845.39 | Shares 100
Sale 20 Dec 2018
Value US$84,630.00 | Price 846.30 | Shares 100
Sale 15 May 2018
Value US$89,206.00 | Price 892.06 | Shares 100
Sale 15 May 2018
Value US$4,465.85 | Price 893.17 | Shares 5
Sale 15 May 2018
Value US$84,852.10 | Price 893.18 | Shares 95
Sale 15 May 2018
Value US$89,310.00 | Price 893.10 | Shares 100
Sale 15 May 2018
Value US$178,252.00 | Price 891.26 | Shares 200
Sale 15 May 2018
Value US$89,125.00 | Price 891.25 | Shares 100
Sale 15 May 2018
Value US$88,920.00 | Price 889.20 | Shares 100
Sale 15 May 2018
Value US$88,942.00 | Price 889.42 | Shares 100
Sale 15 May 2018
Value US$88,822.00 | Price 888.22 | Shares 100
Abbreviations B: Buy, S: Sell, PP: Planned purchase, PlS: Planned sale, PrS: Proposed sale, O: Option / Other
Notification date Transaction date B/S Transaction type Insider and/or position Nb. shares
Price
Value 		Number of shares Price Value Details
2025-12-22 2025-12-19 S Sale
1.4
Rountree George Manning

Chief Executive Officer

Executive Director
64,663 -13.9%
295.86
US$1,163,454 		64,663 -13.9% 295.86 US$1,163,454
2025-12-16 2025-12-16 S Sale
1.0
Gelston Philip A
Non-Executive Director
90,373 +20.0%
15.30
US$3,864,972 		90,373 +20.0% 15.30 US$3,864,972
2023-11-20 2023-11-17 B Purchase
2.4
Hicks Weston M
Non-Executive Director
84,147 -27.6%
209.24
US$608,608 		84,147 -27.6% 209.24 US$608,608
2023-11-20 2023-11-17 B Purchase
2.4
Hicks Weston M
Non-Executive Director
11 +0.5%
1,483.43
US$16,318 		11 +0.5% 1,483.43 US$16,318
2023-11-20 2023-11-17 B Purchase
2.4
Hicks Weston M
Non-Executive Director
579 +39.2%
1,479.88
US$856,851 		579 +39.2% 1,479.88 US$856,851
2023-11-20 2023-11-17 B Purchase
2.4
Hicks Weston M
Non-Executive Director
120 +8.8%
1,476.74
US$177,209 		120 +8.8% 1,476.74 US$177,209
2023-11-20 2023-11-17 B Purchase
2.4
Hicks Weston M
Non-Executive Director
52 +4.0%
1,476.15
US$76,760 		52 +4.0% 1,476.15 US$76,760
2022-12-27 2022-12-22 S Sale
1.9
Hildreth Michaela

MD & Chief Accounting Officer

Officer
100 -6.4%
1,371.84
US$137,184 		100 -6.4% 1,371.84 US$137,184
2022-09-22 2022-09-20 S Sale
2.8
Carlson Peter M
Non-Executive Director
200 -20.2%
1,400.00
US$280,000 		200 -20.2% 1,400.00 US$280,000
2022-09-22 2022-09-20 S Sale
2.7
DAVIS MORGAN W
Non-Executive Director
945 -12.0%
1,400.00
US$1,323,000 		945 -12.0% 1,400.00 US$1,323,000
2022-06-01 2022-05-31 S Sale
1.9
Hildreth Michaela

MD & Chief Accounting Officer

Officer
100 -6.0%
1,270.94
US$127,094 		100 -6.0% 1,270.94 US$127,094
2021-02-11 2021-02-09 S Sale
2.7
DAVIS MORGAN W
Non-Executive Director
337 -32.0%
1,117.00
US$376,429 		337 -32.0% 1,117.00 US$376,429
2021-02-11 2021-02-09 S Sale
2.7
DAVIS MORGAN W
Non-Executive Director
1,163 -52.5%
1,138.00
US$1,323,494 		1,163 -52.5% 1,138.00 US$1,323,494
2020-03-25 2020-03-24 B Purchase
2.7
DAVIS MORGAN W
Non-Executive Director
50 +0.7%
785.00
US$39,250 		50 +0.7% 785.00 US$39,250
2020-03-25 2020-03-24 B Purchase
2.7
DAVIS MORGAN W
Non-Executive Director
610 +8.7%
782.60
US$477,386 		610 +8.7% 782.60 US$477,386
2020-03-25 2020-03-24 B Purchase
2.7
DAVIS MORGAN W
Non-Executive Director
390 +5.9%
715.00
US$278,850 		390 +5.9% 715.00 US$278,850
2019-12-11 2019-12-10 S Sale SMITH LOWNDES ANDREW Non-Executive Director
200 -15.4%
1,105.76
US$221,152 		200 -15.4% 1,105.76 US$221,152
2019-08-09 2019-08-08 S Sale SMITH LOWNDES ANDREW Non-Executive Director
721 -35.6%
1,085.51
US$782,653 		721 -35.6% 1,085.51 US$782,653
2019-08-09 2019-08-08 S Sale SMITH LOWNDES ANDREW Non-Executive Director
279 -12.1%
1,088.01
US$303,555 		279 -12.1% 1,088.01 US$303,555
2019-06-26 2019-06-24 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel
10 -0.1%
1,052.31
US$10,523 		10 -0.1% 1,052.31 US$10,523
2019-06-26 2019-06-24 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel
103 -0.9%
1,049.00
US$108,047 		103 -0.9% 1,049.00 US$108,047
2019-06-26 2019-06-24 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel
70 -0.6%
1,048.14
US$73,370 		70 -0.6% 1,048.14 US$73,370
2019-06-26 2019-06-24 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel
657 -5.3%
1,046.93
US$687,833 		657 -5.3% 1,046.93 US$687,833
2019-06-26 2019-06-24 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel
160 -1.3%
1,039.50
US$166,320 		160 -1.3% 1,039.50 US$166,320
2019-06-20 2019-06-18 S Sale
1.0
PALMER JESS BRIAN

Chief Accounting Officer
431 -26.6%
1,016.57
US$438,142 		431 -26.6% 1,016.57 US$438,142
2019-06-10 2019-06-10 S Sale
3.0
SMITH LOWNDES ANDREW
300 -11.5%
1,004.24
US$301,272 		300 -11.5% 1,004.24 US$301,272
2019-06-10 2019-06-10 S Sale
3.0
SMITH LOWNDES ANDREW
200 -7.1%
1,005.40
US$201,080 		200 -7.1% 1,005.40 US$201,080
2019-05-10 2019-05-09 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
60 -0.5%
975.00
US$58,500 		60 -0.5% 975.00 US$58,500
2019-05-10 2019-05-09 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
860 -6.4%
977.34
US$840,512 		860 -6.4% 977.34 US$840,512
2019-05-10 2019-05-09 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
80 -0.6%
979.62
US$78,370 		80 -0.6% 979.62 US$78,370
2019-05-10 2019-05-09 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
83 -0.6%
985.20
US$81,772 		83 -0.6% 985.20 US$81,772
2019-04-25 2019-04-25 S Sale
2.7
DAVIS MORGAN W
554 -15.6%
928.40
US$514,334 		554 -15.6% 928.40 US$514,334
2019-04-25 2019-04-23 PlS Planned sale
2.7
DAVIS MORGAN W
696 -16.4%
910.11
US$633,437 		696 -16.4% 910.11 US$633,437
2019-04-17 2019-04-16 PlS Planned sale
2.7
DAVIS MORGAN W
354 -7.7%
912.90
US$323,167 		354 -7.7% 912.90 US$323,167
2019-04-12 2019-04-12 S Sale
2.7
DAVIS MORGAN W
585 -11.3%
916.95
US$536,416 		585 -11.3% 916.95 US$536,416
2019-04-12 2019-04-10 PlS Planned sale
2.7
DAVIS MORGAN W
412 -7.4%
914.99
US$376,976 		412 -7.4% 914.99 US$376,976
2019-04-05 2019-04-04 PlS Planned sale
2.7
DAVIS MORGAN W
910 -14.0%
923.65
US$840,522 		910 -14.0% 923.65 US$840,522
2019-04-02 2019-04-02 S Sale
2.7
DAVIS MORGAN W
362 -5.3%
925.00
US$334,850 		362 -5.3% 925.00 US$334,850
2019-04-02 2019-04-01 PlS Planned sale
2.7
DAVIS MORGAN W
852 -11.0%
924.15
US$787,376 		852 -11.0% 924.15 US$787,376
2019-03-28 2019-03-27 PlS Planned sale
2.7
DAVIS MORGAN W
601 -7.2%
922.66
US$554,519 		601 -7.2% 922.66 US$554,519
2019-03-27 2019-03-26 B Purchase
2.9
Tanner David Allen
Non-Executive Director
495 +256.5%
918.46
US$454,638 		495 +256.5% 918.46 US$454,638
2019-03-27 2019-03-26 B Purchase
2.9
Tanner David Allen
Non-Executive Director
5 +2.7%
917.05
US$4,585 		5 +2.7% 917.05 US$4,585
2019-03-26 2019-03-26 S Sale
3.0
SMITH LOWNDES ANDREW
400 -13.6%
916.70
US$366,680 		400 -13.6% 916.70 US$366,680
2019-03-25 2019-03-22 PlS Planned sale
2.7
DAVIS MORGAN W
709 -7.8%
914.00
US$648,026 		709 -7.8% 914.00 US$648,026
2019-03-20 2019-03-19 PlS Planned sale
2.7
DAVIS MORGAN W
Non-Executive Director
954 -9.6%
925.21
US$882,650 		954 -9.6% 925.21 US$882,650
2019-03-14 2019-03-13 PlS Planned sale
2.7
DAVIS MORGAN W
Non-Executive Director
631 -5.9%
907.94
US$572,910 		631 -5.9% 907.94 US$572,910
2019-03-13 2019-03-12 S Sale
1.3
Brouillette Yves
Non-Executive Director
424 -10.2%
903.19
US$382,953 		424 -10.2% 903.19 US$382,953
2019-03-13 2019-03-12 S Sale
1.3
Brouillette Yves
Non-Executive Director
283 -6.4%
904.15
US$255,874 		283 -6.4% 904.15 US$255,874
2019-03-13 2019-03-12 S Sale
1.3
Brouillette Yves
Non-Executive Director
400 -8.3%
905.00
US$362,000 		400 -8.3% 905.00 US$362,000
2019-03-13 2019-03-12 S Sale
1.3
Brouillette Yves
Non-Executive Director
161 -3.2%
908.00
US$146,188 		161 -3.2% 908.00 US$146,188
2019-03-13 2019-03-11 S Sale
1.3
Brouillette Yves
Non-Executive Director
900 -15.3%
907.48
US$816,732 		900 -15.3% 907.48 US$816,732
2019-03-13 2019-03-11 S Sale
1.3
Brouillette Yves
Non-Executive Director
574 -8.9%
910.05
US$522,369 		574 -8.9% 910.05 US$522,369
2019-03-13 2019-03-11 S Sale
1.3
Brouillette Yves
Non-Executive Director
14 -0.2%
911.06
US$12,755 		14 -0.2% 911.06 US$12,755
2019-03-13 2019-03-11 S Sale
1.3
Brouillette Yves
Non-Executive Director
12 -0.2%
912.40
US$10,949 		12 -0.2% 912.40 US$10,949
2019-03-13 2019-03-11 S Sale
1.3
Brouillette Yves
Non-Executive Director
61 -0.9%
915.00
US$55,815 		61 -0.9% 915.00 US$55,815
2019-03-13 2019-03-11 S Sale
1.3
Brouillette Yves
Non-Executive Director
192 -2.8%
916.18
US$175,907 		192 -2.8% 916.18 US$175,907
2019-03-13 2019-03-11 S Sale
1.3
Brouillette Yves
Non-Executive Director
211 -3.0%
917.00
US$193,487 		211 -3.0% 917.00 US$193,487
2019-03-13 2019-03-11 S Sale
1.3
Brouillette Yves
Non-Executive Director
128 -1.8%
918.61
US$117,582 		128 -1.8% 918.61 US$117,582
2019-03-07 2019-03-06 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
1,000 -6.8%
958.49
US$958,490 		1,000 -6.8% 958.49 US$958,490
2019-03-07 2019-03-05 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
846 -5.5%
949.98
US$803,683 		846 -5.5% 949.98 US$803,683
2019-03-07 2019-03-05 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
9 -0.1%
950.11
US$8,551 		9 -0.1% 950.11 US$8,551
2019-03-07 2019-03-05 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
50 -0.3%
950.25
US$47,512 		50 -0.3% 950.25 US$47,512
2019-03-07 2019-03-05 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
82 -0.5%
951.00
US$77,982 		82 -0.5% 951.00 US$77,982
2019-03-07 2019-03-05 S Sale
2.0
SEELIG ROBERT LAWRENCE

EVP & General Counsel

Officer
13 -0.1%
951.10
US$12,364 		13 -0.1% 951.10 US$12,364
2018-12-21 2018-12-20 S Sale SMITH LOWNDES ANDREW Non-Executive Director
100 -3.3%
845.39
US$84,539 		100 -3.3% 845.39 US$84,539
2018-12-21 2018-12-20 S Sale SMITH LOWNDES ANDREW Non-Executive Director
100 -3.2%
846.30
US$84,630 		100 -3.2% 846.30 US$84,630
2018-05-16 2018-05-15 S Sale DAVIS MORGAN W Non-Executive Director
100 -0.6%
892.06
US$89,206 		100 -0.6% 892.06 US$89,206
2018-05-16 2018-05-15 S Sale DAVIS MORGAN W Non-Executive Director
5 -0.0%
893.17
US$4,466 		5 -0.0% 893.17 US$4,466
2018-05-16 2018-05-15 S Sale DAVIS MORGAN W Non-Executive Director
95 -0.5%
893.18
US$84,852 		95 -0.5% 893.18 US$84,852
2018-05-16 2018-05-15 S Sale DAVIS MORGAN W Non-Executive Director
100 -0.6%
893.10
US$89,310 		100 -0.6% 893.10 US$89,310
2018-05-16 2018-05-15 S Sale DAVIS MORGAN W Non-Executive Director
200 -1.1%
891.26
US$178,252 		200 -1.1% 891.26 US$178,252
2018-05-16 2018-05-15 S Sale DAVIS MORGAN W Non-Executive Director
100 -0.6%
891.25
US$89,125 		100 -0.6% 891.25 US$89,125
2018-05-16 2018-05-15 S Sale DAVIS MORGAN W Non-Executive Director
100 -0.6%
889.20
US$88,920 		100 -0.6% 889.20 US$88,920
2018-05-16 2018-05-15 S Sale DAVIS MORGAN W Non-Executive Director
100 -0.6%
889.42
US$88,942 		100 -0.6% 889.42 US$88,942
2018-05-16 2018-05-15 S Sale DAVIS MORGAN W Non-Executive Director
100 -0.6%
888.22
US$88,822 		100 -0.6% 888.22 US$88,822
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