NEW YORK (Reuters) - Shares of U.S. health insurer Cigna Corp (CI.N: Quote, Profile, Research) rose 8 percent on Tuesday after it closed its acquisition of Great-West Healthcare and said the deal would boost earnings starting this year.

The acquisition, which Cigna announced in November, will add about 1.4 million members to the company's medical enrollment. Cigna is paying $1.5 billion in cash for Great-West and also plans to inject $400 million to support the business.

The Philadelphia-based company, which did not quantify how much the acquisition will add to earnings, said savings or other deal benefits would stem from managing medical costs, operating expense efficiency and membership growth.

Acquiring Denver-based Great-West will help Cigna gain a stronger foothold in markets in the West and Northwest, while broadening its reach among smaller employers, according to the company.

Cigna will also be able to sell specialty products, such as dental and disability insurance, and disease management programs, to Great-West's mid-size and large customers.

"The deal complements Cigna's traditional focus on larger customers," Wachovia analyst Matt Perry said in a research note. Perry estimated the deal would add 2 cents per share to Cigna's earnings in 2008 and 30 cents per share in 2009.

Cigna shares rose $3.25 to $43.82 in afternoon trading on the New York Stock Exchange, leading a broad upswing among health-insurer stocks.

(Reporting by Lewis Krauskopf, editing by Dave Zimmerman)