683 Capital Management’s Amentum Holdings AMTM Stock Holding History

683 Capital Management’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 Q2	$22.7M	Buy	1,100,000 +325,000	+42%	+$7.86M	1.12%	24
2026 Q1	$20.2M	Sell	775,000 -60,000	-7%	-$1.88M	1.05%	23
2025 Q4	$24.2M	Sell	835,000 -440,000	-35%	-$11.2M	1.05%	20
2025 Q3	$30.5M	Sell	1,275,000 -355,000	-22%	-$8.64M	1.6%	16
2025 Q2	$38.5M	Buy	1,630,000 +617,000	+61%	+$12.9M	2.53%	10
2025 Q1	$18.4M	Buy	1,013,000 +588,000	+138%	+$12M	1.27%	22
2024 Q4	$8.94M	Buy	+425,000	New	+$11M	0.55%	46

Other funds holding AMTM

American Securities New York $3.75B AUM 23.12% 1-Year Est. Return

Invesco Atlanta, Georgia $1.26T AUM 61.52% 1-Year Est. Return

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

Primecap Management Pasadena, California $169B AUM 114.72% 1-Year Est. Return

Vanguard Portfolio Management Malvern, Pennsylvania $2.22T AUM

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

Dimensional Fund Advisors Austin, Texas $552B AUM 44.19% 1-Year Est. Return

State Street Boston, Massachusetts $3.37T AUM 44.26% 1-Year Est. Return

FCM

Frontier Capital Management Boston, Massachusetts $10.7B AUM 67.78% 1-Year Est. Return

683 Capital Management's AMTM Position: Q2 2026 in Review

683 Capital Management increased its Amentum Holdings (AMTM) stake by 42% in Q2 2026, buying an estimated $7.86M and bringing the position to 1,100,000 shares worth $22.7M. The position accounts for 1.12% of the portfolio, ranked #24.

683 Capital Management first reported a position in AMTM in Q4 2024 and has held it in 7 quarters since. The position peaked at $38.5M in Q2 2025. 460 funds tracked by Wall St. Rank hold AMTM as of Q2 2026.

683 Capital Management held 1,100,000 shares of Amentum Holdings worth $22.7M as of Q2 2026.
683 Capital Management bought 325,000 Amentum Holdings shares in Q2 2026, an estimated $7.86M.
Amentum Holdings made up 1.12% of 683 Capital Management's portfolio in Q2 2026, its #24 holding.
683 Capital Management first reported a position in Amentum Holdings in Q4 2024 and has held it in 7 quarters since.
683 Capital Management's Amentum Holdings position peaked at $38.5M in Q2 2025.
460 funds tracked by Wall St. Rank held Amentum Holdings as of Q2 2026.

Based on 683 Capital Management's 13F filing for Q2 2026, filed 14 Aug 2026.