What does SIP mean for an electronic stock exchange?
Securities Information Processor. They're the ones that
implement "the tape". For example, IBM trades on multiple
exchanges/ECNs. Each exchange/ECN reports bid/ask and prints trades
to a common reporting facility - the SIP. For NYSE,AMEX listed
securites, the SIP is the CTA (Consolidated Tape Association) and
they disseminate this information real-time through the market data
feeds CTS (Consolidated Tape System) and CQS (Consolidated Quote
Syetem). NASDAQ-listed securities have their own SIP and tape
system, as do the options market.