This paper explores whether MiFID and Reg NMS could be accepted as equivalents by regulators on both sides of the Atlantic. Apart from many similarities, the most important one being that the main purpose of both measures is to enforce best execution in equity trading, there are many differences as well in the definition of best execution, the structures of the markets, and the role and powers of supervisory authorities. It calls upon the European Commission to make a detailed comparison between both measures and to take the opportunity to negotiate a mutual recognition agreement with the US.