Straight Through Processing
(STP)
Also known as: No Dealing Desk, NDD
STP brokers pass client orders straight to liquidity providers (banks, prime brokers, ECNs) with no manual intervention. The broker's revenue comes from a markup added to the raw spread (e.g. 0.3 pips on top of the LP's quote).
STP execution is generally more transparent than dealing-desk (market-maker) execution, with less requoting and less conflict of interest. Pure STP brokers are rare; many hybrid models exist that STP some flow and internalize the rest.