[yummyfajitas]

The housing bubble was a special case. It was more or less impossible to short until fairly late in the game (i.e. approximately the time when Burry actually did) - the market for CDS was not very liquid until synthetic CDOs came into the picture.

[nissimk]

I'm pretty sure that it's also quite difficult to go short on non publicly traded equity.

[Ankaios]

Are there any swaps or other tools that provide a reasonable mechanism?