3 ms·
Not all exchanges do time-based priority. For example, the Philadelphia Stock Exchange (PSX) operated by NASDAQ uses a pro-rata allocation based on order size
by andrewla 15y ago
Not all exchanges do time-based priority. For example, the Philadelphia Stock Exchange (PSX) operated by NASDAQ uses a pro-rata allocation based on order size at a given price level. See rule 3307, "Book Processing", at http://nasdaqomxphlx.cchwallstreet.com/NASDAQOMXPHLXTools/PlatformViewer.asp?selectednode=chp_1_3&manual=%2Fnasdaqomxphlx%2Fphlx%2Fphlx-rulesbrd%2F http://nasdaqomxphlx.cchwallstreet.com/NASDAQOMXPHLXTools/Pl....