CFD orders are done on a first-in-first-out basis. Positions that were initiated first would be liquidated first. Assume you bought 5 lots of ABC CFD at $5.69 and another 2 lots at $5.67. When you sell, your positions opened at $5.69 will be liquidated first.
Partially Done Orders
Market orders, which are also known as hit-the-market orders, are subject to fills based on prevailing market volume. If there is not enough volume at that price level, orders will be partially filled at the available volume and the remaining order will be a queue order.
Basics to CFD Trading