As the system crashes, There will be a point where they will have to sell their physical assets and even some of their Bitcoin but not all, but even so they will be ahead of other corporations because they will have some Bitcoin left and other corporations won't have any Bitcoin whatsoever.
Discussion
I agree, that certainly could happen and they probably don't have to sell any bitcoin, just let the shareholders get completely wiped out.
However, I think they will sell because of greed and temptation. Someone on Wall Street or the banks will want to get it and spend it.