This means Aubrey borrowed a whole bunch of money using his stock as collateral probably to buy boats and ranches and more CHK stock, so when the stock price plummeted by 70% or more like it did, the bankers just sell you out to pay off your loans.

FORBES: Aubrey's Gone Let's Sing A Song

So the Federal Reserve agreed to lend it tens of billions of dollars, taking AIG stock as collateral.

NPR: U.S. Boosts AIG Bailout Package

Big banks and asset managers will have to do a better job of keeping track of margin requirements and the available stock of eligible collateral they have.

ECONOMIST: Collateral management