Isthmus Partners’s White Mountains Insurance WTM Stock Holding History

Isthmus Partners’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
2025 Q3	–	Sell	-164	Closed	-$294K	–	226
2025 Q2	$294K	Hold	164	–	–	0.03%	188
2025 Q1	$316K	Hold	164	–	–	0.04%	178
2024 Q4	$319K	Hold	164	–	–	0.04%	177
2024 Q3	$278K	Hold	164	–	–	0.03%	179
2024 Q2	$298K	Hold	164	–	–	0.04%	168
2024 Q1	$294K	Hold	164	–	–	0.03%	172
2023 Q4	$247K	Hold	164	–	–	0.03%	184
2023 Q3	$245K	Hold	164	–	–	0.04%	158
2023 Q2	$228K	Hold	164	–	–	0.03%	161
2023 Q1	$226K	Hold	164	–	–	0.03%	160
2022 Q4	$232K	Hold	164	–	–	0.03%	161
2022 Q3	$214K	Buy	+164	New	+$212K	0.04%	158

Other funds holding WTM

Vanguard Group Malvern, Pennsylvania $6.9T AUM 27.45% 1-Year Est. Return

Dimensional Fund Advisors Austin, Texas $481B AUM 30.42% 1-Year Est. Return

Morgan Stanley New York $1.66T AUM 25.57% 1-Year Est. Return

Neuberger Berman Group New York $131B AUM 28.36% 1-Year Est. Return

BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return

RRAM

River Road Asset Management Louisville, Kentucky $8.99B AUM 12.83% 1-Year Est. Return

Fuller & Thaler Asset Management San Mateo, California $29.7B AUM 43.33% 1-Year Est. Return

Cooke & Bieler Philadelphia, Pennsylvania $8.84B AUM 6.92% 1-Year Est. Return

FMI

Fiduciary Management Inc Milwaukee, Wisconsin $8.06B AUM 6.78% 1-Year Est. Return

Boston Partners Boston, Massachusetts $95.5B AUM 28.4% 1-Year Est. Return

Isthmus Partners's WTM Position: Q3 2025 in Review

Isthmus Partners sold out of White Mountains Insurance (WTM) in Q3 2025, closing a stake of 164 shares — an estimated $294K sold.

Isthmus Partners first reported a position in WTM in Q3 2022 and held it in 12 quarters. The position peaked at $319K in Q4 2024. 338 funds tracked by Wall St. Rank hold WTM as of Q3 2025.

Isthmus Partners reported no remaining White Mountains Insurance position as of Q3 2025 after selling out during the quarter.
Isthmus Partners sold 164 White Mountains Insurance shares in Q3 2025, an estimated $294K.
Isthmus Partners first reported a position in White Mountains Insurance in Q3 2022 and held it in 12 quarters.
Isthmus Partners's White Mountains Insurance position peaked at $319K in Q4 2024.
338 funds tracked by Wall St. Rank held White Mountains Insurance as of Q3 2025.

Based on Isthmus Partners's 13F filing for Q3 2025, filed 10 Nov 2025.