(Reuters) - U.S. health insurer Cigna Group ( CI ) has revived efforts to merge with smaller rival Humana after abandoning the pursuit late last year, Bloomberg News reported on Friday, citing people familiar with the matter.

The companies have held informal, early discussions recently about a potential deal, the report said.

Shares of Humana were up about 5% in after-hours trading on Friday, while those of Cigna ( CI ) were down about 2%.

Last year, Reuters reported that Cigna ( CI ) ended its attempt to negotiate an acquisition of Humana after the pair failed to agree on a price.

Cigna ( CI ) did not immediately respond to a Reuters request for comment while Humana declined to comment.