Hedge Funds.

A market you and I can't play.

This is where rich guys buy insurance at 2% that a certain investment bond won't lose money , with money they don't have. (hey its deregulated)

2% of a billion is 20 million.

Then later they sell insurance on an investment bond (after rumors are spread) at an even higher rate of 4% to insure the "suspicious" investment bond.

They have hedged their bet coming and going, up or down.

Selling short: Betting that a company will fail in the most pure sense of gambling.