The Securities and Exchange Commission ("Commission" or "SEC") is amending Regulation National Market System ("Regulation NMS") under the Securities Exchange Act of 1934 ("Exchange Act") to modernize the national market system for the collection, consolidation, and dissemination of information with respect to quotations for and transactions in national market system ("NMS") stocks ("NMS information"). Specifically, the Commission is expanding the content of NMS information that is required to be collected, consolidated, and disseminated as part of the national market system under Regulation NMS and is amending the method by which such NMS information is collected, calculated, and disseminated by fostering a competitive environment for the dissemination of NMS information via a decentralized consolidation model with competing consolidators.