If you allow the value to go to zero, shareholders will just turn a blind eye and write the investment off as a loss on their taxes. Writing off a loss on your

If you allow the value to go to zero, shareholders will just turn a blind eye and write the investment off as a loss on their taxes. Writing off a loss on your taxes does not cancel out that loss, it only lessens it a bit. Shareholders still lose lots of money if the company they hold shares in goes bankrupt. Perhaps you already understood that, but your comment makes it sound like you think tax writeoffs mean that shares can go to zero and the shareholders won't ultimately lose anything. This is very much not the case.