Cigna (NYSE:) and Humana (NYSE:) are in talks to combine in a stock-and-cash deal, the Wall Street Journal reported Wednesday afternoon citing people familiar with the matter. A deal to merge could be finalized by the end of the year, it was added.

The news sent shares of both health-insurance companies lower in mid-day trading, with Cigna last trading down 5.9% and Humana down 1.5%.

If an agreement is reached, the merged company would rival UnitedHealth Group (NYSE:) and CVS Health (NYSE:) in size.

Cigna had revenue of about $181 billion last year, while Humana posted revenue of $93 billion.

In 2015, Cigna and Humana considered merging, yet Humana opted for a deal with Aetna. However, this alliance faced antitrust issues and was blocked by a judge. Consequently, Aetna was acquired by CVS in 2018. Another attempt to merge Cigna with Anthem, rebranded as Elevance Health Inc (NYSE:), also fell through due to an unfavorable antitrust ruling.

To alleviate antitrust worries, Cigna is considering selling its current Medicare Advantage division, potentially bringing in billions through this divestment.