The DMM Function
A Designated Market Maker (DMM) on the NYSE has specific obligations: providing continuous two-sided quotes in assigned securities, facilitating orderly trading, and managing openings and closings. DMMs are compensated through access to order flow and trading advantages. Citadel Securities is the largest DMM on the NYSE, having expanded through acquisitions including IMC's NYSE market-making unit in 2020.
Wholesale Market Making vs. DMM
Citadel Securities operates in two distinct market-making modes. As a DMM, it has exchange-specific obligations and is directly regulated by NYSE. As a wholesale market maker receiving PFOF, it operates in the off-exchange (OTC) market, subject to FINRA's oversight. The combination of exchange-based DMM activities and off-exchange PFOF market-making gives Citadel unparalleled visibility into order flow across the market.
Information Advantages
A market maker that sees a large fraction of retail order flow — before that flow hits public markets — has significant informational advantages. Knowing the direction and magnitude of retail demand allows a market maker to position itself advantageously. This is not necessarily illegal — market makers are entitled to use their market information — but it raises structural questions about whether retail investors' order information is being used in ways that benefit them or the market maker.
Systemic Importance
Citadel Securities' scale means it is, in effect, systemically important to U.S. equity markets. A major operational failure at Citadel could disrupt market-making in hundreds of securities simultaneously. This systemic importance has not, according to public records, resulted in formal designation as a systemically important financial institution (SIFI) or equivalent regulatory status. In The Ethics Reporter's view, the question of whether Citadel Securities warrants enhanced systemic oversight is a legitimate regulatory question.