从这里查到的：网页链接

“Sometimes after a reorganization, a company will issue new stock that is considered different from the pre-reorganization stock. If this occurs, investors will need to know whether the company has given its shareholders the opportunity to exchange the old stock for new stock, because the old stock will usually be considered useless when the new stock is issued.”

911之后，United Airline也是Chapter11，四年以后（2/1/2006）走出Chapter11，现在网上看到股价历史是2/6/2006开始，所以很有可能旧股真的成了废纸，但是我不确定。只是不明白大家现在还在买卖啥？