The growth ambitions of China's insurers could be hindered by some of the companies' opaque structures when they pursue acquisitions in international markets, a banker at Citigroup Inc. said.

"It is not that straightforward with Chinese companies," Gautam Chawla, co-head of the global insurance group at Citigroup Inc., said Wednesday at a conference in New York held by Reactions magazine. "The level of transparency that we are used to is not the same level of transparency that they are used to."

Anbang Insurance Group Co. withdrew an application in May to buy Des Moines, Iowa-based Fidelity & Guaranty Life. New York's watchdog had reservations about Anbang's ownership structure and how it would fund reserves, people familiar with the application said that month. Anbang has renewed discussions with regulators to win approval for the $1.6 billion deal, according to people with knowledge of the talks. Anbang has said it is committed to completing the deal.

More-established companies from Japan have had an easier time pushing into the world's largest economy. Sumitomo Life Insurance Co., Tokio Marine Holdings Inc. and Dai-ichi Life Insurance Co. have all announced acquisitions in the past two years to expand in the U.S.

"The Japanese companies are well known globally," Chawla said. "They're well known with the regulators."

While a variety of companies from China have been expanding globally, insurers may expect more difficulty, according to the banker. He said potential sellers may spend more time before agreeing to a deal with a Chinese company so that they can make sure that the would-be buyer will win approval.

"Investing in a regulated industry like insurance is very different," he said.