The Illinois Department of Insurance approved Hartford, Conn.-based Aetna's $34 billion acquisition of Louisville, Ky.-based Humana Thursday.
The department's Acting Director Anne Melissa Dowling determined the acquisition would not impede Medicare Advantage plan competition, as members could still purchase traditional Medicare if dissatisfied with combined Aetna-Humana Medicare plans.
The U.S. Department of Justice has the final say in the deal, and is also reviewing how the combined Medicare Advantage business could affect the elderly and disabled, Reuters reported.
Aetna announced plans to acquire Humana in July 2015. Seventeen out of the 20 required states have approved the transaction, an Aetna spokesperson told Reuters.
Recently, the California Department of Managed Health approved the deal and the Missouri Department of Insurance's preliminary order did not.
Aetna's acquisition of Humana is slated to be completed by the second half of 2016.