Over the counter securities trade on a Bulletin Board offered by the National Association of Security Dealers. If the stock is on the bulletin board, it will have a ".ob" suffix.
OTC Bulletin Board
An electronic listing of over-the-counter securities on NASDAQ. The OTCBB lists several thousand securities, including stocks, bonds, ADRs, and others. Since 1999, the SEC has required all companies listed on the OTCBB to report their financial information.