Which of the following are examples of trading systems?

• A. Electronic communications networks (ECN)
• B. Dark pools and lit pools
• C. Electronic communications networks (ECN), crossing networks and call markets
• D. Over-the-counter markets

Answer: (C)

Trading systems are the mechanisms that match buy and sell orders. An ECN is an electronic system that automatically matches orders on a centralized network. A crossing network is another type of trading system that matches orders internally, often for large blocks, without exposing them to the broader market. A call market is an auction-based trading system that gathers orders and executes at a single price at a specific time. Together, these three represent formal ways to match trades across different formats (electronic matching, internal crosses, and auction-based matching).

Dark pools and lit pools describe types of trading venues, but the question focuses on representative systems, and over-the-counter markets are bilateral, dealer-driven trades rather than centralized trading systems.