Designated market maker (DMM)
Also known as: specialist
A designated market maker (DMM) is a firm on the New York Stock Exchange responsible for maintaining a fair and orderly market in its assigned stocks. DMMs quote continuous two-sided markets and manage the opening and closing auctions.
A designated market maker (DMM) is an exchange member firm assigned to specific stocks on the New York Stock Exchange, with an obligation to maintain a fair and orderly market in those securities. Each NYSE-listed stock has exactly one DMM, though a DMM firm typically handles many stocks. The role evolved from the exchange's original "specialist" system, and older exam materials sometimes still use that term.
DMMs quote two-sided markets — a bid and an offer — throughout the trading day and are expected to commit their own capital when buying or selling interest is out of balance. By stepping in as buyer when sellers dominate and as seller when buyers dominate, the DMM dampens temporary price swings. DMMs also run the opening and closing auctions that set each stock's official opening and closing prices, matching accumulated orders at a single price.
Most NYSE volume is handled electronically through the exchange's order-matching systems (historically known as the Super Display Book), so the DMM's job centers on supplying liquidity and managing auctions rather than manually pairing every order. This differs from NASDAQ, a dealer market where many competing market makers quote each security instead of a single assigned firm.
The Series 7, Series 65, and Series 66 exams test how the secondary markets are organized. Know that the NYSE is an auction market with one DMM per stock responsible for fair and orderly trading, while NASDAQ relies on multiple competing market makers quoting bids and offers electronically.
Key takeaways
- A DMM is the NYSE member firm assigned to maintain a fair and orderly market in specific listed stocks.
- Each NYSE stock has one DMM; the role replaced the older specialist system.
- DMMs quote continuous two-sided markets, commit capital to offset order imbalances, and run the opening and closing auctions.
- On exams, contrast the NYSE's single-DMM auction market with NASDAQ's multiple competing market makers.