What are the main reasons AIG failed?

What are the main reasons AIG failed?

AIG was accruing unpaid debts—collateral it owed its credit default swap partners, but did not have to hand over due to the agreements’ collateral provisions. But when AIG’s credit rating was lowered, those collateral provisions kicked in—and AIG suddenly owed its counterparties a great deal of money. Aug 3, 2015