In the past quarter of a century, the pace of structural change in the equity markets has accelerated dramatically and, as it has, regulation has come to play an increasingly central role in the development of market structure. The purpose of Regulation of U.S. Equity Markets is to consider regulation's contribution to the efficiency of the U.S. equity markets. Sharply different opinions are expressed on the matter, as the discussion ranges from Congressional oversight, to SEC involvement in market structure issues, to the self-regulatory responsibilities of the market centers, most notably, the New York Stock Exchange and the Nasdaq Stock Market.