2010/9/1 賣出4份Future at 1.8690
2010/9/1 買入250000英鎊 at 1.8654
Future 盈虧 = (1.8690-1.8425)*62,500*4 = 6625
SPOT 盈虧 = (1.8420 - 1.8654)*250,000 = -5,850
最後結果 盈虧 = 6625 - 5850 = 775
合約數 = 250,000/62,500 = 4