This is a deal that the broker (see) doesn't close on the same day, but carries it over to the next. So when a new trading session (see) starts, the broker closes the deal and then opens it again. This is called a "swap" (see), it earned the broker commission for the transfering it through the night. So your transaction is closed at the market price, and opened at either the purchase price (Ask - see) or the sale price (Bid - see). These prices are always different from what you can see in the terminal, by exactly the amount of commission that taken by the broker. If you don't want to ever pay this commission, before opening an account, put a tick in the “No swap account” box.
Trading in financial markets involves substantial risks, including complete possible loss of investment capital. This activity is not suitable for all investors. High leverage increases the risk (Risk Disclosure).