The National Market System (NMS) is the national system for trading in the United States.
The System includes all the facilities and entities which are used by broker-dealers to fulfill trade orders for securities. This includes:
The NASDAQ Stock Market, commonly known as the NASDAQ, is an American stock exchange. In terms of market share and volume traded, it is the largest stock exchange in the U.S. The exchange platform is owned by The NASDAQ OMX Group, which also owns the OMX stock market network and several other U.S. stock and options exchanges.
The Federal Deposit Insurance Corporation, the Office of the Comptroller of Currency, the Federal Reserve Board of Governors, and the Federal Open Market Committee all together impact the payment systems used for settlement on securities markets, both directly by regulations and indirectly via monetary policy which affects the value of the dollar.
The Commodity Futures Trading Commission is an important regulator for commodities futures and options.
The U.S. Securities and Exchange Commission is the most important federal regulator of corporate stocks, as well as other securities.
One of the most important elements of the National Market System is that all qualified trades are reported onto a consolidated system.