liquidity the order can be partially executed while the rest will be displayed and seen on the marketplace; Market depth can be provided via a special add-in module to show the depth of the market also known as Level 2 – a measure of the size of volume available for transaction purposes for a particular instrument at a particular point of time. The best Offer (ASK) and the best bid are displayed in a table with the size available to buy or sell. Market depth displays orders that are currently in the market. When two orders match (buy and sell orders at the same price), they are filled and disappear from the market depth and the deal is registered in the trade history. Difficulties of true ECN trading for retail traders Price volatility can be greater in comparison to quotes of market makers who may use fluctuations filtering while the NDD model provides direct access to the interbank foreign exchange market. Market makers' quotes are not related to the volume, i.e. orders may be filled at the offered price without any relation to the deal volume. While using the ECN the market presents the liquidity that is currently available, i.e. orders will be executed in the volume available at this certain price. Bid–offer spread can vary significantly with market conditions reflecting actual interbank market prices which can cause problems with stops. Market Makers will typically hold spreads at a fixed level to avoid confusion for retail traders and avoid stops and limits being hit when prices are unstable. Additional order execution latency is introduced due to the necessity of executing the trade with a liquidity provider. See also Foreign exchange market Direct access trading References External links The US Securities and Exchange Commission Investopedia Financial software Financial markets Technical analysis software Electronic trading systems