Explainer-Why prior mega health insurer deals like the possible Cigna/Humana merger failed

WASHINGTON (Reuters) - U.S. health insurers Cigna and Humana are in talks to merge, a potential deal likely to face aggressive scrutiny from the U.S. Justice Department (DOJ) if antitrust history with similarly sized deals is any indication. The deal could exceed $60 billion in value.

The DOJ in 2017 successfully stopped Anthem, now Elevance Health, from buying Cigna for $54 billion, and thwarted Aetna's plan to purchase rival Humana for $34 billion. Here's a look at what happened with those deals first announced in 2015.

WHAT WAS THE RATIONALE FOR THE PROPOSED MERGERS?

Aetna, Humana, Anthem and Cigna cited the Affordable Care Act, popularly known as Obamacare, which was passed by Congress in 2010 to significantly expand access to affordable health insurance. They said aspects of the new law meant their industry needed to consolidate to cope with the costs of expanding coverage.

WHAT DID THE JUSTICE DEPARTMENT SAY IN ITS COMPLAINTS?

In each of the two complaints filed in federal court in Washington in 2016, the Justice Department noted the other deal and the extraordinary consolidation that was being planned for the industry. It asked federal judges to order each transaction stopped.