When American International Group Inc. disclosed that it would slice about $2.7 billion, or 3.3percent, off its net worth because of accounting issues, the biggest single chunk stemmed from dealings with an obscure Barbados company.

Details are now emerging about Union Excess Reinsurance Co., including names of some of its investors during the 1990s. Investor lists from then show seven insurers outside the US, including a unit of French insurance titan AXA SA, an insurer tied to Chevron Corp. and two small Bermuda operations, according to people familiar with the lists.

The details shed light on relationships among the companies and individuals with roles at Union Excess. American International Group is a big customer of several Union Excess investors, some of which also have ties to other offshore ventures that have drawn regulatory scrutiny. State and federal authorities investigating AIG?s accounting are interested in Union Excess?s structure. AIG attorneys have said AIG intentionally misled regulators about at least one transaction with Union Excess and about AIG?s control over another offshore firm, Richmond Insurance Co. AIG says it is cooperating with all investigations.

AIG?s transactions with Union Excess account for about $1.1 billion of the expected hit to its net worth. In detailing its accounting woes in recent statements, the big insurer said its ?control over certain transactions undertaken directly or indirectly? with the reinsurer meant it couldn?t treat those deals as reinsurance. Insurers buy reinsurance to spread the risk of losses from the policies they sell. In doing so, insurers move claims liabilities off their own books.

To count as reinsurance, the transaction must transfer significant risk of loss to the reinsurer. In addition, AIG said it should consolidate Union Excess?s results with its own, because of ?certain facts and circumstances related to the formation of Union Excess?, as well as because of ties between Union Excess and Starr International Co., a Bermuda investment company historically run by AIG executives.

Starr provided a guarantee of sorts that protected ?a significant portion of the ownership interests of Union Excess shareholders.? Chevron acquired its Union Excess stake through its merger with Texaco ? which invested through a Bermuda-based insurance unit, Heddington Insurance Ltd., in 1993, the year Union Excess was founded, Chevron spokesman Andy Norman said. Records show Heddington also owned about ten percent of Richmond, another offshore reinsurer whose financial results AIG has said it will consolidate with its own. Heddington?s former president and chief executive is Robert C. Golden, an insurance-industry veteran who previously headed Texaco?s risk operations and served on boards, including at XL Capital Ltd. Mr. Golden also is listed as a one percent owner of Richmond in a 1986 share register obtained by newsletter KYC News.

?Heddington has never used Union Excess for reinsurance purposes,? Mr. Norman said, but it isn?t clear why Heddington invested in Union Excess. Mr. Golden couldn?t be reached to comment yesterday.

Another investor, the people familiar with the investor lists said, has been Western General Insurance Co., a Bermuda-based insurer indirectly owned by Chicago?s Pritzker family, the Hyatt Hotel chain?s owners. Western General?s president and general manager, insurance-industry veteran John L. Marion, served on the boards of both Union Excess and Richmond during the early 1990s, and was a vice president of Richmond, according to biographical material in a prospectus for another company. Mr. Marion didn?t return calls to his office. A person answering Western General?s telephone said the closely held firm doesn?t respond to press inquiries. A Pritzker family attorney couldn?t be reached to comment.

UK insurer Aviva PLC acquired ?passive stakes? in Union Excess and another Barbados reinsurer with ties to AIG ? now-defunct Coral Reinsurance Co. ? in 1994, upon acquiring insurer Abeille from French conglomerate Suez SA, an Aviva spokeswoman said. The Union Excess stake has since been reduced to three percent from six percent, and the Coral stake was ?very small?, she said.

Coral was set up by investment-banking firm Goldman Sachs Group Inc. in the mid-1980s to sell reinsurance to AIG. AIG came under scrutiny from state insurance regulators in the mid-1990s for allegedly undisclosed ties to Coral, a relationship AIG defended as legitimate. But as scrutiny mounted, AIG unwound its ties to Coral. AXA also owns about three percent of Union Excess, acquired in 1995 when it bought an Abeille reinsurance unit, said spokeswoman Clara Rodrigo.

AXA doesn?t currently do business with Union Excess, she said.

Another investor, Overseas Partners Ltd., formerly an offshore reinsurer for United Parcel Service Inc., didn?t return calls; a UPS spokesman declined to comment. A spokesman for Bank of Bermuda, parent to investor Woodbourne Insurance Ltd., declined to comment. A representative for another investor, Antares Ltd., couldn?t be reached.

Bermuda incorporation records say Woodbourne was dissolved in late 2000. AIG, the world?s biggest reinsurance buyer, does business with at least three Union Excess investors. Of $885 million in reinsurance proceeds that Western General was obligated as of December 31 to pay to US insurers, 90 percent was owed to AIG, state regulatory filings show. About 38 percent of such payments from Overseas Partners was owed to AIG, and about 12 percent of Heddington?s, the records show.