Burry figured that he could bet against pools of these subprime mortgage loans using an instrument called a "credit default swap," essentially insurance on a corporate loan. Burry persuaded the investment banks to create credit default swaps for the subprime mortgage market.
"As the pools of loans that are underneath these bonds start to default," Lewis says, the investment banks that gambled on the subprime mortgage loans were forced to send Burry money daily as the bonds went bad. "Wall Street firms, they were on the other side of the bets."
And in the clip, they talk about how AIG was where the Wall Street firms got their money.