Primecap Management’s Amentum Holdings AMTM Stock Holding History

Primecap 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	$254M	Buy	12,285,504 +200,210	+2%	+$4.84M	0.15%	105
2026 Q1	$315M	Sell	12,085,294 -41,633	-0.3%	-$1.31M	0.25%	81
2025 Q4	$352M	Buy	12,126,927 +208,341	+2%	+$5.33M	0.27%	80
2025 Q3	$285M	Sell	11,918,586 -112,070	-0.9%	-$2.73M	0.22%	89
2025 Q2	$284M	Buy	12,030,656 +1,969,067	+20%	+$41.2M	0.23%	84
2025 Q1	$183M	Buy	10,061,589 +3,647,210	+57%	+$74.3M	0.15%	100
2024 Q4	$135M	Buy	6,414,379 +1,143,097	+22%	+$29.5M	0.1%	125
2024 Q3	$170M	Buy	+5,271,282	New	+$150M	0.13%	109

Other funds holding AMTM

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

BlackRock New York $6.73T AUM 46.02% 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

TCA

Troluce Capital Advisors Dorado, Puerto Rico $971M AUM 2.27% 1-Year Est. Return

Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return

Primecap Management's AMTM Position: Q2 2026 in Review

Primecap Management increased its Amentum Holdings (AMTM) stake by 1.7% in Q2 2026, buying an estimated $4.84M and bringing the position to 12,285,504 shares worth $254M. The position accounts for 0.15% of the portfolio, ranked #105.

Primecap Management first reported a position in AMTM in Q3 2024 and has held it in 8 quarters since. The position peaked at $352M in Q4 2025. 458 funds tracked by Wall St. Rank hold AMTM as of Q2 2026.

Primecap Management held 12,285,504 shares of Amentum Holdings worth $254M as of Q2 2026.
Primecap Management bought 200,210 Amentum Holdings shares in Q2 2026, an estimated $4.84M.
Amentum Holdings made up 0.15% of Primecap Management's portfolio in Q2 2026, its #105 holding.
Primecap Management first reported a position in Amentum Holdings in Q3 2024 and has held it in 8 quarters since.
Primecap Management's Amentum Holdings position peaked at $352M in Q4 2025.
458 funds tracked by Wall St. Rank held Amentum Holdings as of Q2 2026.

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