Because unfortunately, there are a lot of people who don't understand what a bankruptcy filing means. Once a company files, regardless of whether its Chapter. 7 or 11, the stock is worthless. People think they can scoop up shares for pennies, in the hopes that some savior appears and bails the company out. There are no possibilities of that, once the filing takes place. If you still hold stock at this point, I suggest you get whatever you can for it before the SEC suspends trading.