over the counter (OTC) market

1. UK: No OTC market on the pattern of the US exists but unlisted securities are traded on the Alternative Investment Market of the London Stock Exchange (LSE).

2. US: OTC securities trading system in which brokers or dealers (called market makers) negotiate over telephone or computerized networks instead of through a stock exchange. Trading rules for this market are established and enforced by the National Association Of Securities Dealers. In dollar terms, it is the largest securities market in the US. Also called outside market or third market. See also NASDAQ.