AMENTUM HOLDINGS INC

Ticker: AMTM CUSIP: 023939101 Class: COM

FRONTIER CAPITAL MANAGEMENT CO LLC's Holding History (CIK: 0000351173)

Note: Option positions (PUT/CALL) are excluded.

Q4 2025

Shares 5,772,976 Value ($000) $167,416 Avg Close $25.56 Range $21.11 - $31.87

Q3 2025

Shares 5,202,680 Value ($000) $124,604 Avg Close $24.35 Range $21.71 - $26.63

Q2 2025

Shares 5,460,743 Value ($000) $128,928 Avg Close $20.90 Range $16.01 - $24.33

Q1 2025

Shares 3,578,732 Value ($000) $65,133 Avg Close $20.37 Range $16.95 - $24.30

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2025	5,772,976	$167,416	$25.56	$21.11 - $31.87
Q3 2025	5,202,680	$124,604	$24.35	$21.71 - $26.63
Q2 2025	5,460,743	$128,928	$20.90	$16.01 - $24.33
Q1 2025	3,578,732	$65,133	$20.37	$16.95 - $24.30