In addition to common rules of order execution set by a broker, a trade can indicate additional conditions in the "Fill Policy" field of the order placing window:
Fill or Kill This execution policy means that an order can be executed only in the specified volume. If the necessary amount of a financial instrument is currently unavailable in the market, the order will not be executed. The required volume can be filled by several offers available on the market at the moment.
Immediate or Cancel In this case a trader agrees to execute a deal with the volume maximally available in the market within that indicated in the order. In case the order cannot be filled completely, the available volume of the order will be filled, and the remaining volume will be canceled. The possibility of using IOC orders is determined on the trade server.
Return This policy is only used for market (Buy and Sell), limit and stop limit orders. If filled partially, an order with the remaining volume is not canceled, and is processed further. For market orders, the Return policy is used only in the Exchange Execution mode, while for limit and stop limit ones, it is applied in the Market Execution and Exchange Execution modes.
Use of fill policies depending on the execution type can be shown as the following table: