Behind Insurer’s Crisis: Caught in a Web of Risk

Days later, federal officials, who had let Lehman die and initially balked at tossing a lifeline to A.I.G., ended up bailing out the insurer for $85 billion.

Their message was simple: Lehman was expendable. But if A.I.G. unspooled, so could some of the mightiest enterprises in the world.

A Goldman spokesman said in an interview that the firm was never imperiled by A.I.G.’s troubles and that Mr. Blankfein participated in the Fed discussions to safeguard the entire financial system, not his firm’s own interests.

Yet an exploration of A.I.G.’s demise and its relationships with firms like Goldman offers important insights into the mystifying, virally connected — and astonishingly fragile — financial world that began to implode in recent weeks.