On Monday, U.S. District Judge John Bates blocked Hartford, Conn.-based Aetna's proposed $37 billion takeover of Louisville, Ky.-based Humana.
Here are five things to know.
1. The judge wrote the proposed acquisition "is likely to substantially lessen competition in the sale of individual Medicare Advantage plans in 364 counties identified in the complaint and in the sale of individual commercial insurance on the public exchanges in three counties in Florida identified in the complaint," Hartford Courant reports.
2. Judge Bates determined Medicare Advantage and traditional Medicare should not be considered the same market. He said the deal violates antitrust laws as Aetna and Humana would have a monopolistic Medicare Advantage market share.
3. Aetna spokesperson T.J. Crawford said in a statement to Bloomberg, "We're reviewing the opinion now and giving serious consideration to an appeal after putting forward a compelling case." A response from Humana was not immediately available, according to the report.
4. Under the merger agreement, Aetna owes Humana a $1 billion breakup fee.
5. Aetna and Humana shares had dropped more than 2 percent Monday following the decision. Long Beach, Calif.-based Molina Healthcare, which would have gained assets divested by Aetna and Humana to counter the Justice Department's antitrust arguments, dropped about 2 percent as well.