The New York Stock Exchange (NYSE) filed rule changes that propose a significant transformation of its current market structure. Among other things, the rule proposals would redefine the role of specialists on NYSE by creating a new category of Designated Market Makers (DMMs) and formally eliminating the specialist category. The rule changes would also increase market participants’ ability to post hidden liquidity on the NYSE trading platform and would modify certain key aspects of the current NYSE rules dealing with priority and parity.