Sometimes it's not always clear what happened to a stock after it stopped being traded. Mergers, dissolutions and name changes can throw you off the trail. There are several print and database resources that can help determine whether or not your shares have value.
Each state has a Secretary of State which tracks the companies that are incorporated or operating within its borders and their history. If you know which state your company was incorporated in you can search their databases for information.
Some states do not post detailed information online either by law or due to technological constraints. You may have to go in person to view the records or you may have to pay a fee for that office to find/scan the records for you.
Linked below is the Secretary of the Commonwealth on Massachusetts Corporations division. The Secretary of the Commonwealth provides ample information in regards to company information:
How long the records are available in each state varies. The Secretary of the Commonwealth has digitized its card catalog of older companies. Linked below is the Corporate Card Catalog:
The Capital Changes Reporter will give you a comprehensive history of many companies and their securities. This resource requires that you make an account and is not available remotely. Search by company name.
Additional resources are at Kirstein Business Library and Innovation Center, Lower Level of the Johnson Building, Central Library at Copley Square.
Directory of Obsolete Securities (Financial Information, Inc.)
This book includes company information from 1926 through the present.
Fifteen volumes spanning over one hundred years of securities information, this source lists the name of the obsolete company, the state in which it was incorporated, and the year in which the stock became worthless. Occasionally, an explanation is provided for a stock’s demise. [Note: Updates have been made at irregular intervals since 1926, resulting in a tricky indexing structure]. Some Canadian stocks can also be found in these manuals.]