Just five months ago, Taiwan's Financial Supervisory Commission nixed American International Group Inc.'s (NYSE:AIG) deal to sell Nan Shan Life Insurance Co. Ltd. to Hong Kong private equity firm Primus Financial Holdings Ltd. and local investment holding company China Strategic Holdings Ltd. Some observers chalked it up to the would-be buyers' lack of insurance experience. So what would lead AIG to believe the regulator would greenlight a sale of Nan Shan to footwear maker Pou Chen Corp. and Taiwanese conglomerate Ruentex Group, which appears to dabble in everything but insurance?

According to a Wednesday report from Taiwan's Central News Agency, the FSC last December issued guidelines that AIG must follow in seeking a Nan Shan buyer that included the requirement that a buyer demonstrate an ability to run an insurance company and commit to operate Nan Shan for the long term.

AIG president and chief executive Robert Benmosche stated that Ruentex "offers strong operational and funding capabilities and possesses a clear ability to satisfy the strict criteria that governed AIG's bid review process."

Ruentex's wide array of businesses includes textile, garment, retail, construction and development, financial, distribution, medical services and education operations, according to the company's website.

A person familiar with the situation pointed to Ruentex's "investments and involvement" in ING Antai Life Insurance Co., formerly Aetna Life Taiwan, which last year merged with local competitor Fubon Financial Holding Co. Ltd. It is unclear what that "involvement" entailed and whether Ruentex is still invested in that business.

David Merkel, principal of Baltimore investment manager Aleph Investments LLC and a former AIG life actuary, said he is "puzzled" by the Ruentex news, due to questions about the buyer's operational ability.

More puzzling is that the deal was made amid reported interest from Fubon Financial and Taiwanese insurer Cathay Financial Holding Co. Ltd. AIG did not confirm those media reports, but disclosed in a regulatory filing that other prospective buyers have approached AIG with unsolicited offers at prices ranging from $2.15 billion to $3 billion.

So, Ruentex's offer was near the bottom of the price range? Even more puzzling.

Merkel said that the only issue that may have steered AIG away from Fubon and Cathay could be concerns that the Taiwanese regulator might be bent on preventing an increase in concentration among Taiwan's top insurers.

Of course, these questions could be partly answered by AIG's statement that the buyer has "expressed its intention to retain the current Nan Shan management team."

Puzzle unsolved until the FSC decides.