Aetna will purchase Coventry Health Care in a $7.3 billion deal, including Coventry debt, that will allow the health care benefit company to bolster its Medicare and Medicaid rolls.

Coventry stockholders will receive $27.30 in cash and 0.3885 Aetna shares per Coventry share, or $42.08 per Coventry share based on Aetna’s Aug. 17 closing price. The deal is expected to close in mid-2013.