The SEC has proposed rescinding Rule 611 of Regulation NMS (Order Protection Rule), which prohibits so-called “trade-throughs” of national market system (NMS) stocks, and Rule 610(e), which requires exchanges to restrict locking and crossing quotations in NMS stocks. The SEC believes that eliminating the rules would have many benefits, including reducing market complexity, improving price discovery and lowering costs for market participants. This article parses the rulemaking release, with commentary on the implications of the proposed changes for hedge fund managers from W. Hardy Callcott, partner at Sidley Austin LLP, and Susan Schroeder, partner at WilmerHale. For more on the NMS, see our three-part series on the SEC’s enhanced order routing disclosures: “How New Disclosures Shed Light on Rebates Paid to Broker-Dealers” (Mar. 28, 2019); “Understanding Rule 606(a) and Rule 606(b)(3) Reports” (Apr. 4, 2019); and “How Fund Managers Should Use These Additional Disclosures Going Forward” (Apr. 11, 2019).