Designated Market Maker/ DMM
Definition - What does Designated Market Maker/ DMM mean?
A member of an exchange responsible for maintaining a fair and orderly market in the securities for which they are the designated market maker / DMM and for executing orders left with them.
Testopedia explains Designated Market Maker/ DMM
The NYSE began calling the Specialists in securities designated market markers when the exchange implemented its hybrid trading system. This trading platform combines the advantages of the specialist system, where a live person monitors the trading activity, with the technological advantages of computer based trading.