Depending on the interest rates of the two currencies involved, the forward foreign exchange rate:
In error, your dealer enters a trade whereby he buys GBP 8,000,000.00 against USD at 1.5500, but manages to cover it at the same rate. When the initial mistaken trade is cancelled, however, the rate has since changed to 1.5200. What is the effect on P&L?
What risks arise from not receiving the securities purchased or not receiving payment for securities sold?