(Reuters) – Humana Inc. is considering selling itself after receiving multiple expressions of takeover interest, a person familiar with the matter said on Friday, highlighting the potential for further consolidation in the U.S. health insurance industry.

Humana is working with investment bank Goldman Sachs Group Inc on the potential sale, the person said, asking not to be identified because the matter is confidential.

The Wall Street Journal first reported on the sale process and said competitors Aetna Inc. and Cigna Corp. are among those that have held preliminary merger discussions with Humana.

Humana, whose shares rose as much as 23% on the news, could not be immediately reached for comment. Goldman Sachs, Cigna and Aetna declined to comment.

Speculation that there will be consolidation among the five publicly traded health insurers has increased in recent weeks, as executives from companies such as Aetna and Anthem Inc. have said they are interested in doing large deals.

Humana had a market value of $26.72 billion as of Thursday’s close. The Louisville, Kentucky-based company specializes in Medicare health insurance and drug plans for the elderly and disabled.

The company’s top shareholders include Glenview Capital Management, which in the past has pushed for change at hospital operator Health Management Associates Inc.

Some of the company’s shareholders had privately called on the company in recent months to explore a sale, people familiar with the matter said this week. They asked not to be identified because those discussions were confidential.

The Justice Department, which reviews insurance mergers, will scrutinize any deal coming out of these talks city-by-city to see if the combined company would have a monopoly in any metropolitan area, said Andre Barlow, a veteran of the Justice Department now at Washington law firm Doyle, Barlow and Mazard P.L.L.C.

“Humana is going to be selling itself to another mega player and the antitrust division has shown itself to be interested in scrutinizing mega mergers. The deal could be met with some resistance,” said Mr. Barlow. “It’s not like they block everything but they have scrutinized these mega deals.”