What a NYSE DMM Does
A NYSE Designated Market Maker is assigned specific securities and has obligations in those securities: maintaining continuous two-sided quotes, facilitating orderly openings and closings, managing price discovery during imbalanced conditions, and providing liquidity during volatile periods. In exchange, DMMs receive preferential access to order flow in their assigned securities.
The IMC Acquisition
In October 2020, Citadel Securities announced its acquisition of IMC's NYSE market-making unit. This acquisition expanded Citadel's DMM portfolio substantially, making it the largest DMM on the NYSE. The acquisition was part of Citadel's strategy to expand its exchange-based market-making alongside its off-exchange PFOF operations.
DMM Obligations During Volatility
NYSE DMMs are expected to provide stabilizing quotes during volatile trading — buying when others are selling and selling when others are buying. During opening and closing auctions, DMMs play a critical role in establishing reference prices. The quality of DMM performance during volatile periods directly affects market quality in their assigned securities.
Concentration of DMM Capacity
With Citadel Securities as the largest NYSE DMM, a significant fraction of NYSE-listed securities depend on Citadel for their exchange-based liquidity provision. This concentration means that Citadel's operational reliability is important not just for retail market-making but for the functioning of the NYSE itself in assigned securities.