According to the NYSE only Broker Dealers are allowed to have membership and membership is a pre-requisite to be a MM at NYSE. https://www.nyse.com/markets/nyse-arca/membership
https://www.nyse.com/publicdocs/nyse/markets/nyse/NYSE_Exchanges_Market_Maker_Orientation.pdf
https://www.nyse.com/publicdocs/nyse/markets/nyse/NYSE_Exchanges_Market_Maker_Orientation.pdf
