A. We turned to the Securities and Exchange Commission (SEC) for help with this question <www.sec.gov/>. According to the SEC, old stock certificates may be valuable even if the company name has vanished from the market; the company may have merged with another one or changed its name. The SEC recommends these reference guides, available in many libraries (or in your stockbroker's office), to trace the "family tree" of old stocks:

• Financial Stock Guide Service (Financial Information, Inc., 30 Montgomery St., Box 473, Jersey City, NJ 07303): Comprehensive guide published since 1927, including a directory of actively traded stocks and obsolete securities plus a brief profile of companies whose original identities have been lost.