Corizon, a health care provider for correctional facilities, forms out of the $250-million merger of Brentwood-based America Service Group with Valitas Health Services, each of which operates a correctional health care subsidiary (Prison Health Services [PHS] and Correctional Medical Services, respectively).

The combined company will rebrand as Corizon, a provider of health care services to more than 400 of prisons, jails and other correctional facilities around the country.

PHS CEO Rich Hallworth navigates the merger and leads the new company until 2013.