Market Maker

A market maker provides liquidity for a particular currency pair and stands ready to buy or sell that currency by displaying a bid and offer price. A market maker takes the opposite side of your trade and has the option of holding that position or partially or fully offsetting it with other dealers, managing their aggregate exposure to the market. Market makers earn their commission from the spread between the bid and offer price.

Forex ECN Broker

ECN is an acronym for Electronic Communications Network. A Forex ECN does not operate a dealing desk but instead provides a marketplace where multiple market makers, banks and traders can enter competing bids and offers into the platform either inside or outside the spread, allowing traders to trade against each other and with multiple counterparties. A trader might open a trade with liquidity provider "A" and close it with liquidity provider "B", or have the trade executed against the bid or offer of another trader. Participants of the ECN send in competing bids and offers into the platform and the combined volume is usually displayed to traders at each price. Orders are matched between counterparties, usually for a small fee.

NDD

An acronym for 'No Dealing Desk'. A no-dealing desk broker uses a matching engine to match up orders between its liquidity providers and their clients. The liquidity providers send in competing bids and offers into the platform, resulting in the best bid and offer being displayed to the trader. A no dealing desk broker may increase the spread instead of charging a commission to their clients.