Used for listed equity securities. System used in an auction market, in which the first bid or offer price is executed before other bid and offer prices, even if subsequent orders are larger. NYSE rules stipulate that the bid made first should be executed first, or if two bids came in at once, the bid for the large number of shares receives "priority." The bid not executed is then turned to the broker, who informs the customer that the trade was not completed because there was stock ahead. See: Standing.