In general, dealer markets are represented physically only by phone, fax, and internet lines; i.e., there is no single physical trading floor or centralized marketplace. Dealers buy and sell for themselves, at their own risk. Dealer markets in stocks and long-term debt are called over-the-counter (OTC) markets. Today a significant fraction of the market for stock and almost all of the market for long-term debt have no central location; the many dealers are connected electronically.

In 1971, the National Association of Securities Dealers (NASD) made available to dealers and brokers an electronic quotation system called NASDAQ. There are roughly three times as many companies on Nasdaq as there are on NYSE, but they tend to be much smaller in size and trade less actively. There are exceptions, of course. Both Microsoft and Intel trade OTC, for example. Nonetheless. the total value of Nasdaq stocks is only about 20 percent of the total value of NYSE stocks.