If the purchase of a foreign currency is greater than the sale, its "foreign exchange trading" subject is the credit balance, commonly known as "long position"; Conversely, if the purchase is less than the sale, the "foreign exchange trading" account is the debit balance, commonly known as "short". When the exchange rate of a foreign currency against RMB shows an upward trend, for banks, foreign currency "bulls" will benefit and "bears" will suffer losses; On the contrary, if the exchange rate shows a downward trend, "bears" are favorable and "bulls" are unfavorable.