Cigna Corp. announced Wednesday it completed its purchase of Medicare Advantage plans from Arcadian and Humana in Arkansas, Oklahoma and Texas.

Starting Jan. 1, about 4,500 Medicare Advantage customers who had Humana or Arcadian now have Cigna coverage, which includes HealthSpring. The acquisition includes 35 new counties in and around Amarillo, Texas; Longview-Marshall, Texas; Texarkana, Texas; and Fort Smith, Ark.

The deal was announced in June. Terms of the agreement, including the price, were not disclosed.

The federal government required Humana to sell the Medicare Advantage plans as part of approval for buying Arcadian Management Services. Cigna will offer the new customers Medicare Advantage plans through its subsidiary HealthSpring, which the Bloomfield-based health insurer acquired in January for $3.8 billion.

Humana's divestiture also opens up Arkansas and Oklahoma as a new market to HealthSpring for the first time. HealthSpring already has about 94,000 Medicare Advantage customers in Texas in 51 counties and it will add 10 more. Separately, the company has a Medicaid business in Texas.