Q. Where can I find information on obsolete securities?

Go to Cheetah (formerly IntelliConnect, formerly CCH Internet Research Network).

• From the Cheetah homepage, use the Practice Areas box to select Securities - Federal & International.
• Scroll down until the Capital Changes box is visible, then select Worthless Securities. 
• You can view an alphabetical list or search by company name.

You could also search through All Content by keyword, for example, capital histories AND xerox to find a specific instance of interest.

Go to How can I find out if an old stock certificate has value? - U.S. Securities and Exchange Commission.