Jane Street’s Amentum Holdings AMTM Stock Holding History

Jane Street’s Portfolio AMTM Stock Details AMTM Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2026 Q3	$3.99M	Buy	220,300 +82,600	+60%	+$1.73M	﹤0.01%	4055
2026 Q2	$2.85M	Sell	137,700 -1,600	-1%	-$38.7K	﹤0.01%	4592
2026 Q1	$3.63M	Buy	139,300 +64,100	+85%	+$2.01M	﹤0.01%	4011
2025 Q4	$2.18M	Sell	75,200 -19,120	-20%	-$489K	﹤0.01%	4651
2025 Q3	$2.26M	Sell	94,320 -1,624	-2%	-$39.5K	﹤0.01%	4715
2025 Q2	$2.27M	Sell	95,944 -241,556	-72%	-$5.05M	﹤0.01%	4232
2025 Q1	$6.14M	Buy	337,500 +173,000	+105%	+$3.52M	﹤0.01%	2617
2024 Q4	$3.46M	Buy	+164,500	New	+$4.25M	﹤0.01%	3204

Other funds holding AMTM

American Securities New York $2.69B AUM 8.08% 1-Year Est. Return

Invesco Atlanta, Georgia $1.27T AUM 50.62% 1-Year Est. Return

BlackRock New York $6.79T AUM 37.06% 1-Year Est. Return

Primecap Management Pasadena, California $161B AUM 86.05% 1-Year Est. Return

Vanguard Portfolio Management Malvern, Pennsylvania $2.21T AUM

Dimensional Fund Advisors Austin, Texas $551B AUM 33.95% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.76T AUM

Fidelity Investments Boston, Massachusetts $2.32T AUM 44.66% 1-Year Est. Return

State Street Boston, Massachusetts $3.44T AUM 36.12% 1-Year Est. Return

Thompson Siegel & Walmsley Richmond, Virginia $5.37B AUM 3.99% 1-Year Est. Return

Jane Street's AMTM Position: Q3 2026 in Review

Jane Street reduced its Amentum Holdings (AMTM) stake by 95% in Q3 2026, selling an estimated $6.81M and leaving 18,504 shares worth $335K. The position accounts for ﹤0.01% of the portfolio, ranked #8903.

Jane Street first reported a position in AMTM in Q3 2024 and has held it in 8 quarters since. The position peaked at $11M in Q1 2025. 360 funds tracked by Wall St. Rank hold AMTM as of Q3 2026.

Jane Street held 18,504 shares of Amentum Holdings worth $335K as of Q3 2026.
Jane Street sold 325,183 Amentum Holdings shares in Q3 2026, an estimated $6.81M.
Amentum Holdings made up ﹤0.01% of Jane Street's portfolio in Q3 2026, its #8903 holding.
Jane Street first reported a position in Amentum Holdings in Q3 2024 and has held it in 8 quarters since.
Jane Street's Amentum Holdings position peaked at $11M in Q1 2025.
360 funds tracked by Wall St. Rank held Amentum Holdings as of Q3 2026.

Based on Jane Street's 13F filing for Q3 2026, filed 12 Nov 2026.