[7] Amentum was founded in 2020 as a spinout of the Management Services Group of AECOM, consisting of the non-construction parts of the company's federal work as well as its commercial operations and maintenance business.

This came as a result of a process by AECOM to realign its business to focus more clearly on the architect, engineering, and construction market.

[8] Amentum traces its AECOM roots back to several well-known government contracting firms that now form the basis of its current work.

These firms came to be a part of the company by way of AECOM's acquisition of URS Corporation and include EG&G, Washington Group International, Westinghouse Government Services, and Lear Siegler.

[10] On October 1st, 2024, Amentum became a publicly traded company on the NYSE under the ticker symbol "AMTM", becoming a part of the S&P 500.