Explain the cash first. Generally speaking, the foreign currency cash held by customers or the passbook in which foreign currency cash is deposited is called cash business. Cash refers to the foreign currency transferred from overseas to the customer's passbook through remittance business.

In fact, the most fundamental thing is that as long as it is not transferred from abroad to the passbook through remittance business, it is all cash.

The buying price of cash is lower than that of cash, because a certain handling fee has been charged for remittance from abroad to China, and cash is a foreign currency held by customers themselves, so the buying price of cash is lower than that of cash before.

It's as simple as that, that is, one paid some money before, and then it went up, and the other didn't pay it before, and then it fell.