:: definitions

Traders101.com reproduces this definition here under license for your convenience.

DAT is trading by sending your buy and sell orders directly to the market, rather than via a traditional broker. When people talk about "direct access trading" they usually mean a Level II trading system (e.g. RealTick). With a direct access trading system, a day trader can choose exactly how to route an order. This is either thru an exchange (e.g. CME or NYSE) , a computerised system (ie thru an intermediary electronic communications network - an "ECN"), or a market maker (a 'big' player). The day trader can also send direct orders through a direct access broker, who can execute orders much faster than most online retail brokers such as Ameritrade. As you would imagine, this speed is fairly essential for day traders or those using shorter term trading styles. You will usually pay more for a direct access broker than you would for a standard online retail trading account. Spread betting firms supplying day trading facilities usually charge no commissions, relying on the 'spread' (the difference between the bid and the ask) to make their profit, and to all intents and purposes, such an account is already "direct".