Mariner
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Mariner’s White Mountains Insurance WTM Stock Holding History

Mariner’s Portfolio WTM Stock Details WTM Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q2 		– Sell
-607
Closed -$1.33M – 3931
2026
Q1 		$1.33M Buy
607
+205
+51% +$439K ﹤0.01% 1763
2025
Q4 		$835K Buy
402
+188
+88% +$368K ﹤0.01% 2074
2025
Q3 		$357K Sell
214
-528
-71% -$942K ﹤0.01% 2677
2025
Q2 		$1.33M Buy
742
+22
+3% +$39.1K ﹤0.01% 1613
2025
Q1 		$1.39M Sell
720
-105
-13% -$198K ﹤0.01% 1459
2024
Q4 		$1.6M Buy
825
+151
+22% +$285K ﹤0.01% 1342
2024
Q3 		$1.14M Buy
674
+74
+12% +$129K ﹤0.01% 1505
2024
Q2 		$1.09M Buy
600
+117
+24% +$207K ﹤0.01% 1446
2024
Q1 		$867K Buy
483
+91
+23% +$153K ﹤0.01% 1615
2023
Q4 		$590K Sell
392
-30
-7% -$44.6K ﹤0.01% 1839
2023
Q3 		$631K Buy
422
+79
+23% +$121K ﹤0.01% 1615
2023
Q2 		$476K Sell
343
-4
-1% -$5.63K ﹤0.01% 1781
2023
Q1 		$478K Buy
347
+7
+2% +$10K ﹤0.01% 1726
2022
Q4 		$481K Buy
340
+26
+8% +$35.2K ﹤0.01% 1674
2022
Q3 		$409K Buy
+314
New +$406K ﹤0.01% 1545
2018
Q4 		– Sell
-479
Closed -$448K – 900
2018
Q3 		$448K Sell
479
-834
-64% -$773K 0.01% 580
2018
Q2 		$1.19M Buy
+1,313
New +$1.16M 0.03% 368

Other funds holding WTM

Dimensional Fund Advisors
Dimensional Fund Advisors Austin, Texas $552B AUM 44.19% 1-Year Est. Return
Neuberger Berman Group
Neuberger Berman Group New York $150B AUM 40.08% 1-Year Est. Return
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
RRAM
River Road Asset Management Louisville, Kentucky $8.99B AUM 12.83% 1-Year Est. Return
Vanguard Portfolio Management
Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
Fuller & Thaler Asset Management
Fuller & Thaler Asset Management San Mateo, California $36.7B AUM 74.15% 1-Year Est. Return
CB
Cooke & Bieler Philadelphia, Pennsylvania $8.65B AUM 9.66% 1-Year Est. Return
WCM
Wallace Capital Management Dallas, Texas $912M AUM 21.45% 1-Year Est. Return
FMI
Fiduciary Management Inc Milwaukee, Wisconsin $7.03B AUM 11.68% 1-Year Est. Return

Mariner's WTM Position: Q2 2026 in Review

Mariner sold out of White Mountains Insurance (WTM) in Q2 2026, closing a stake of 607 shares — an estimated $1.33M sold.

Mariner first reported a position in WTM in Q2 2018 and held it in 17 quarters. The position peaked at $1.6M in Q4 2024. 357 funds tracked by Wall St. Rank hold WTM as of Q2 2026.

  • Mariner reported no remaining White Mountains Insurance position as of Q2 2026 after selling out during the quarter.
  • Mariner sold 607 White Mountains Insurance shares in Q2 2026, an estimated $1.33M.
  • Mariner first reported a position in White Mountains Insurance in Q2 2018 and held it in 17 quarters.
  • Mariner's White Mountains Insurance position peaked at $1.6M in Q4 2024.
  • 357 funds tracked by Wall St. Rank held White Mountains Insurance as of Q2 2026.

Based on Mariner's 13F filing for Q2 2026, filed 13 Aug 2026.