Instinet was trading stocks on computer terminals in 1969. Big institutions used it to trade with each other directly, without a floor broker. Reuters bought it in 1987. By the late 1990s Instinet and newer rivals were taking a large share of Nasdaq trading. In May 2001 Reuters sold part of Instinet to the public. A year later Instinet bought Island, an upstart rival that ran its own electronic market.

Anonymous, and After Hours

Instinet bet that buyers and sellers could find each other through a screen and save on costs. It offered anonymity, which mattered to large investors who did not want to tip off the market. Its model set the pattern for modern stock markets, and many of today's trading venues follow it. It also let institutions trade outside normal exchange hours.

Absorbed by Nasdaq

Instinet priced its IPO at $14.50 a share in May 2001 and listed on Nasdaq. Competition from other electronic networks and falling trading fees squeezed it. In 2005 Nasdaq agreed to buy Instinet Group for about $1.9 billion to get its electronic marketplace. The market Instinet built became part of the exchange it had competed with for years. The brokerage arm went to the private equity firm Silver Lake, and later to Nomura.

Cover: Chicago Stock Exchange Trading Room: Reconstruction at the Art Institute of Chicago, Adler & Sullivan, Architects. Art Institute of Chicago, public domain. Chosen for a stock exchange trading room.