China Pacific Insurance, the mainland's third largest insurer, is set to raise up to US$6 billion by listing its shares in Shanghai and Hong Kong, people familiar with the situation said.

The initial public offering (IPO) of mainland A shares is expected to occur as early as next month, with an H-share listing targeted for March next year.

People familiar with the situation said that each listing would raise up to US$3 billion although the A-share portion - representing about 12 percent of the group's enlarged share capital - is tipped to be "slightly bigger" than that of the H share.

The estimated size of the capital raising, of a company launched just six years ago, highlights the dramatic surge in the mainland's equity markets since the life and general insurer first signalled its intention to list two years ago. People close to the situation anticipated last year that a sole Hong Kong listing would raise about US$1 billion.

Over the past year, regulators have encouraged companies to list on the domestic market instead of overseas, in an effort to mop up investor liquidity which has propelled the flagship Shanghai index sixfold since 2005. The listing of the state-owned insurer will deliver a handsome paper profit for a consortium led by Carlyle Group, the US private equity firm, which two years ago acquired a 25 per cent in the group's life assurance arm for US$410 million.

The consortium this year agreed to swap its existing stake and invest an unspecified additional sum in return for a 19.9 percent holding at group level, a move which cleared the path for a listing.

UBS will help to arrange both the A and H-share listings, with Credit Suisse involved in just the Hong Kong offering.

Both investment banks declined to comment.

Founded in 2001, China Pacific's life assurance subsidiary has quickly become the third biggest company in the sector, behind China Life and Ping An, both of which have been listed in Hong Kong for several years.

Shares in China Life more than doubled on their first day of trading in Shanghai in January this year, while the A shares of Ping An have almost quadrupled since it listed in March raising US$5.2 billion.