China Life Insurance Co, the nation's largest insurer, delayed marketing what would be the world's biggest initial stock offer this year, because US regulators haven't cleared the US.5 billion sale, people involved said.

　　Regulators want more information to improve disclosure in the insurer's prospectus, the people said, without giving details. China Life plans to sell at least 25 percent of its stock in Hong Kong and New York by mid-December.

　　"The schedule is pretty tight now and a further delay means the sale may not be completed this year," said Roy Chan, chief representative of DLAsgroupsin Shanghai, a law firm that advises companies on listing and acquisitions. "The company should have expected an onerous US regulatory process due to differences in accounting standards and ways to calculate reserves."

　　The United States has been trying to improve the disclosure of information to investors and corporate governance by companies after clamping down on investment banks for publishing biased research related to share offers they arranged. China's Ping An Insurance Co, China Life's closest rival, dropped a New York listing option as it wants to seek a quicker route to raise funds, bankers involved said in May.

　　China Life, which controls three-quarters of the nation's life insurance market, aims to file its public application to the Securities and Exchange Commission this week. That depends on whether the company can satisfy the US regulator's requirements with the additional information, the people said.

　　"I'm surprised this should come up at this stage," said Wei Yen, a China financial analyst at Moody's Investors Service in Hong Kong. "The plan was to do the sale quickly. If they have accounting issues, that can take a long time to resolve."

　　Officials at the four arrangers of the sale declined to comment. IPR Asia, which was hired by China Life to handle communications for the sale, also declined to comment. Henry Law, a spokesman for the Hong Kong stock exchange, declined to comment and the US regulator wasn't available to comment.

　　Ping An, China's No 2 life insurer, delayed its initial public sale of as much as US.5 billion until next year because it's yet to win approval from the government, which wants state-owned China Life to sell shares first, the bankers said earlier.