All companies can go bankrupt at any moment. I picked up some GM on a whim and a bet it will go up and it has.
Chrysler had no stockholders which made BK easier to jump in and out of, there is much more at stake for Ford and GM being hundreds of thousands of jobs directly and rippled.
Actually I bought a stock at $.50, it went bankrupt but traded in the $.03 range until someone bought the shell and ran it up to $2.00 (now it's at .50 again, but I got out at $1.50).
Sometimes the manure turns into compost.