NEW YORK (Bloomberg) — American International Group Inc. investors trying to derail a US takeover of the insurer may demand a shareholder vote on the $85 billion deal, said a person familiar with the situation.

The investors decided at a New York meeting yesterday to ask AIG for data so they can raise money and keep the U.S. from taking a 79.9 percent stake, said the person, who declined to be identified because talks were private. Maurice (Hank) Greenberg, AIG's ex-chief executive officer, and representatives for Eli Broad, Shelby Davis of Davis Selected Advisers LP and Bill Miller of Legg Mason Inc. attended, said the person.

The insurer, crippled by losses tied to the worst US housing slump since the Great Depression, agreed on September 16 to turn over control to the government in exchange for a federal loan of as much as $85 billion. The original terms said the US would get warrants equal to a 79.9 percent stake, and that shareholder approval would be sought. A new description filed on September 19 omitted any mention of warrants or a shareholder vote.

The investors "discussed possible alternatives that may exist that could relieve the taxpayers' burden while protecting" AIG's customers, policyholders and employees, said Mickey Kantor, a lawyer for the shareholders, in a statement yesterday. "These discussions will continue."

The group is advised by Roger Altman, CEO of Evercore Partners Inc., and may ask AIG for information on its balance sheet, the person said. AIG, the largest US insurer by assets, climbed 87 cents, or 23 percent, to $4.72 in New York Stock Exchange trading.

The shareholders want to make sure that if New York-based AIG pays off its federal loan within the two-year limit, the company will keep or recover the controlling equity stake, the person said. About 35 people, including representatives from Dodge & Cox, met yesterday at the offices of law firm Mayer Brown, where Kantor is a partner.

New York Comptroller Thomas DiNapoli's office was to be represented because the state held 10.8 million AIG shares in a retirement fund as of September 12, his spokesman Jim Fuchs said before the gathering.

"To pull this off strikes me as terrifically tricky," said James Cox, a professor at Duke University who specialises in securities law. "A defensive takeover by investors of their own firm, on this scale, has never happened before."