I wonder if IB will include AMEX routing on BEST execution for Nasdaq NMS stocks. If so, it could get real slow. Amex's Plan for New Listings Will Tread Upon Nasdaq Turf Tue Apr 9, 1:54 AM ET The American Stock Exchange is planning to begin trading 120 of the top Nasdaq Stock Market-listed companies on its own trading floor, Tuesday's Wall Street Journal reported. Though Amex lists and trades the Nasdaq-100 Index Tracking Stock -- popularly known as the QQQ, after its trading symbol -- this is the first full-scale move by the Amex into Nasdaq listing territory. The Amex is trying to increase revenue at the expense of its corporate sibling. The Amex maneuver marks yet another twist in its increasingly awkward relationship with Nasdaq. Both markets are owned by the National Association of Securities Dealers. Nasdaq has spent the past several years orchestrating a spinoff from the NASD. And as Amex hunts for an exit strategy of its own, the two markets have returned to their former roles as rivals for listing stocks and attracting stock order flow. A Nasdaq spokesman declined to comment on the Amex initiative. Under the Amex move, the stocks to be traded include the components of the Nasdaq 100, as well as 20 other frequently traded issues. Amex hopes to begin the new trading, which makes use of a regulatory option allowing markets to trade securities they don't list, on May 20 . The Amex is attempting to take advantage of a difficult time for Nasdaq traders, many of whom have seen their revenue erode since the implementation last spring of decimalized trading of U.S. stocks. That change diminished the gap between buy and sell orders for a stock at a given time, thus shrinking the pool from which traders capture revenue. Wall Street Journal Staff Reporter Kate Kelly contributed to this report.