Ussually, stocks become trash if companies file bankruptcy and shut down. Companies have least obligations to common stock holders. Some people may buy the stocks when the companies almost out of business, e.g. $0.10 to gamble. If the companies can turn around or being bought out by another comapnies, they get huge profits. But usually the companies with serious debts would just close the doors. Then, they open again by using different name to issue stocks and raise tons of moeny again.

Remember Kmart filed the biggest retail bankruptcy ever in the United States in 2002. It released all the bebts and liablitiies. Then, it turned around to use another name Kmart Holding to raise tons of money from issuing new stocks. Later, Kmart meraged with Sears for $11B and shares sky rocketed. Now, SHLD is $178 / share.

It is part of the game in the Wall Street. Big Croporations and lawmakers do control the markets. We are individual investors just have to keep ourselves knowledgeable in order to survive.