Trade Execution Activities

Once an order is entered, it must be routed to a venue for execution. This section covers the differences between exchanges, over-the-counter (OTC) markets, and alternative trading systems, along with the rules around trading halts.


Exchange vs. OTC vs. ATS Execution

VenueHow Orders Are MatchedKey Feature
Exchange (NYSE, Nasdaq exchange)Centralized order book; auction-based matchingPrice/time priority; transparent pre-trade quotes
OTCDealer-to-dealer negotiation or electronic quotation systemsDealers trade from inventory; negotiated prices
Alternative Trading System (ATS)Electronic matching of buy/sell ordersNot an exchange; has subscribers, not members; no regulatory responsibilities

Alternative Trading Systems (Regulation ATS)

  • An ATS brings together multiple buyers and sellers electronically but is not a self-regulatory organization (SRO)
  • ATSs must register as broker-dealers and comply with FINRA rules
  • Dark pools are a type of ATS that do not display pre-trade quotes (no visible bid/ask), designed for large institutional trades to minimize market impact
  • ATSs must register with the SEC on Form ATS at least 20 days before beginning operations
  • All ATS trades in listed securities must be reported to a FINRA Trade Reporting Facility (TRF) and published on the consolidated tape
  • FINRA publishes weekly ATS trading data after a delay for transparency

Key distinction: An ATS has subscribers, not members. Unlike an exchange, it has no regulatory responsibilities over its subscribers.

Think of it this way: An exchange is like a formal auction house with rules, a governing board, and licensed members. An ATS is more like a private matching service: it connects buyers and sellers electronically, but it does not police their behavior the way an exchange does.

Exam Tip: Gotchas

  • An ATS is NOT an exchange and is NOT a self-regulatory organization (SRO). It has subscribers, not members.
  • Dark pools are a type of ATS. They do not display pre-trade quotes, but trades in listed securities still must be reported to the consolidated tape via a FINRA Trade Reporting Facility (TRF).

Trading Halts (FINRA Rules 6120/6121)

  • FINRA may halt OTC trading in any National Market System (NMS) stock when exchanges halt trading
  • Halts may occur due to:
    • Pending material news
    • Regulatory concerns
    • Extraordinary market volatility

Prohibition During Trading Halts (FINRA Rule 5260)

During a trading halt, members may not:

  • Execute transactions in the halted security
  • Publish quotations for the halted security
  • Publish indications of interest in the halted security

Violations may result in disciplinary action.

Exam Tip: Gotchas

  • During a trading halt, all three activities are prohibited: executing transactions, publishing quotations, and publishing indications of interest. The exam may test whether you know that indications of interest are also banned (not just trades and quotes).