Humana and Aetna announced Tuesday morning that they’ve killed their merger, and the insurers have agreed that Aetna will pay Humana the $1 billion breakup fee.

At 4:45 p.m., Humana will release a 2017 earnings forecast and hold a call with investors.

U.S. District Court Judge John D. Bates blocked Hartford, Conn.-based Aetna’s planned acquisition of Louisville-based Humana in late January, citing antitrust concerns. The companies had said they would determine before 11:59 p.m. Wednesday whether to appeal the ruling.

While Humana’s release merely announced the termination of the merger, Aetna CEO Mark Bertolini said in a press release that he still maintains that the merger would have provided better health care to more people at a lower price.

However, he said, “the current environment makes it too challenging to continue pursuing the transaction.

“We are disappointed to take this course of action after 19 months of planning, but both companies need to move forward with their respective strategies in order to continue to meet member expectations. Our mutual respect for our companies’ capabilities has grown throughout this process, and we remain committed to a shared goal of helping drive the shift to a consumer-centric health care system,” Bertolini said.

Aetna said that in mid-March it will redeem for cash $10.2 billion of the remaining debt it had issued to acquire Humana.

As Insider reported Monday, four of the nation’s five biggest insurance giants have hoarded nearly $40 billion in cash and equivalents. The proposed merger of health insurers Anthem and Cigna also had been tied up in court, and just last week a federal judge blocked the deal.  Analysts said the companies could initiate share buybacks to push up their share price or attempt other acquisitions, with both Anthem and Cigna possibly pursuing Humana.

Louisville Mayor Greg Fischer said in a statement that he welcomed a resolution to the proposed merger.

“The work of the Humana associates during this period has been extremely impressive. Humana has been a world-class company throughout its 56-year-history, and I am extremely confident and enthusiastic about its future as an independent company.”

Humana shares fell on the news, and were down 0.38 percent at market close on Tuesday. Aetna’s shares rose 3.1 percent. Broader markets booked gains of about 0.4 percent.