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AMTM — S&P 500 index addition
Amentum Holdings
Sector
Industrials
Announced
Nov 8, 2024
Effective
Nov 15, 2024
Replaced
Added as a Jacobs spin-off
1W after inclusion
-3.1%
-4.4% vs S&P 500
1M after inclusion
-8.5%
-10.2% vs S&P 500
3M after inclusion
-21.4%
-22.7% vs S&P 500
6M after inclusion
-16.7%
-15.1% vs S&P 500
1Y after inclusion
-12.4%
-30.2% vs S&P 500
Indexed performance around the effective date (effective close = 100)
Prices last updated: 2026-09-16 06:30 UTC (9h ago)
Run-up in the 30 days into inclusion: -12.9%
Other stocks added to the S&P 500
- RDDT — Reddit joined on Aug 18, 2026.
- FERG — Ferguson Enterprises joined on Aug 5, 2026.
- HONA — Honeywell Aerospace joined on Jun 29, 2026.
- FLEX — Flex Ltd. joined on Jun 22, 2026.
- MRVL — Marvell Technology joined on Jun 22, 2026.
- FDXF — FedEx Freight joined on Jun 1, 2026.
See the full S&P 500 additions log or the index review calendar.