The U.S. Securities and Exchange Commission has approved the Archipelago Exchange as the first fully electronic national securities exchange in the United States since in 1976.

The SEC approved a proposal of the Pacific Exchange Inc. to establish the Archipelago Exchange as its new, electronic communications and trading facility.

The all-electronic ArcaEx facility will operate in place of the trading floor of the PCX’s subsidiary, PCX Equities Inc., with ArcaEx market makers replacing the traditional floor specialists. The ArcaEx facility is the first fully electronic national securities exchange since the Cincinnati Stock Exchange developed its trading system in 1976.

ArcaEx will feature three trading sessions each day: an early session, a core session, and a late trading session. Members and other users of ArcaEx will submit orders to an electronic file of orders, known as the Arca Book, where all trades will be executed at prices equal to or better than the national best bid or offer.

The Archipelago Exchange LLC owns and operates ArcaEx. The PCX currently has a 10% ownership interest in it, and is responsible for the trading that will take place through ArcaEx, including surveillance.