Acording to good old Investopedia "ONLY NASD MEMBERS THAT FUNCTION AS MARKET MAKERS ARE ALLOWED ACCESSS TO LEVEL III. Here is their definition: Level III This is a trading service consisting of everything in Level II plus the ability to enter quotes, execute orders and send information. This service is restricted to NASD member firms that function as registered market makers. Level III allows you to enter bid/ask quotes as the trades are being executed right in front of you. It is the fastest way to execute a trade and is typically found only on the trading floors of brokerage market makers. It should be noted, the basher side seems to have it "too easy". You can bank they have a corrupt MM giving them access to Level III. Here is the link: http://www.investopedia.com/university/electr...ading7.asp