National market system plan

A national market system plan (or NMS plan) is a structured method of transmitting securities transactions in real-time. In the United States, national market systems are governed by section 11A of the Securities Exchange Act of 1934.

In addition to processing the transactions themselves, these plans also emit the price, volume data, and regulatory auditing information^[1]^[2] for these transactions. Information on each securities trade is sent to a central network at the Securities Industry Automation Corporation (SIAC) where it is then distributed, consolidated with other trades on the same "tape".

There are three major tapes in the United States: Tape A and Tape B (which together are called the "Consolidated Tape"), and Tape C.

^ "The Consolidated Audit Trail". catnmsplan.com. Retrieved 31 May 2017.
^ Michaels, Dave (15 Nov 2016). "SEC Approves Consolidated Audit Trail to Detect Market Manipulation". The Wall Street Journal. Dow Jones & Company, Inc. Retrieved 31 May 2017.

[catnmsplan-com-1] "The Consolidated Audit Trail". catnmsplan.com. Retrieved 31 May 2017.

[2] Michaels, Dave (15 Nov 2016). "SEC Approves Consolidated Audit Trail to Detect Market Manipulation". The Wall Street Journal. Dow Jones & Company, Inc. Retrieved 31 May 2017.

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