US-BASED health and life insurance company Cigna said it will cooperate more closely with China Merchants Bank after the lender bought a 50-percent stake in Cigna's China joint venture Cigna & CMC Life Insurance Company.

"China is an important market to us as life insurance penetration is still low," Jason Sadler, president of Cigna Corp's global individual business, said in Shanghai over the weekend.

The insurer will enhance its cooperation with the bank in providing healthcare and life insurance products, Sadler said, as the Chinese become aware about protection from unforeseen illness and accidents.

Steven Sun, general manager and CEO of Cigna & CMC, said its sales of high-end healthcare insurance products doubled annually in 2012.