The Justice Department is requiring health insurers Humana Inc. and Arcadian Management Services Inc. to divest assets of Arcadian's Medicare Advantage business in five states.
The divestiture is a condition of allowing Humana to acquire Arcadian.
The companies have agreed to the move, which is designed to preserve competition for 71,000 residents of 51 counties and parishes in Arizona, Arkansas, Louisiana, Oklahoma and Texas.
The Justice Department says the original transaction would have eliminated competition between Humana and Arcadian, two of few significant sellers of Medicare Advantage plans, in 45 of the 51 counties and parishes.
Congress gave people eligible for Medicare the choice of enrolling in a privately provided Medicare Advantage plan instead of traditional Medicare.
Humana is headquartered in Louisville, Ky., and Arcadian is headquartered in Oakland, Calif.