The FIA Principal Traders Group recommended that the Securities and Exchange Commission update its Regulation NMS to help improve the regulatory structure of US equity markets. (Regulation NMS or National Market System was designed by the SEC to assure that investors receive the best price for execution by facilitating competition among individual marketplaces and individual orders.) Specifically, the Group proposed that the SEC eliminate its so-called “trade-through rule” and related prohibitions on locked and cross-markets. (The “trade-through rule” effectively requires all market participants to conduct business with all trading venues that display relevant orders, no matter what their market share; in locked markets the bid and ask price is the same; in crossed markets, the best bid exceeds the best ask price.) The Group claimed this action would reduce the need for “hundreds of exchange order types” that are used to avoid trade-throughs, locks and crosses; eliminate complexity for regulators and brokers; and reduce excessive market fragmentation.