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.
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".
The UTP SIP handles Tape C securities and provides two feeds, the UQDF for quotes and the NBBO and the UTDF for trades.
Tape C contains stocks listed on NASDAQ, and is overseen by the UTP Plsn.