= = I checked Baidu and found out

There are many definitions of currency mismatch. This definition is better:

Because an equity entity (including a sovereign country , banks, non-financial enterprises and households) have their revenue and expenditure activities denominated in different currencies, and their assets and liabilities have different currency structures, resulting in their net worth or net income (or both) being very sensitive to changes in exchange rates. , that is, a so-called currency mismatch occurs.

In other words, a subject (any country, enterprise, or family) has income and expenditure involving two currencies.

For example, your company is engaged in foreign trade, importing foreign equipment and selling it in China. Joining the Americans requires your company to pay you US dollars and make credit sales to you. Then you owe a bunch of US dollar debts. If you sell these equipment, you will get a bunch of RMB as short-term capital. In this way, the difference between liabilities measured in U.S. dollars and capital measured in people creates a currency mismatch.

Why is currency mismatch bad? Because it brings risks. For example, for your company, if the RMB depreciates, the U.S. debt you owe will become more expensive. The net equity of the company's statements calculated in RMB will decrease. This is the risk.

Take a country as an example. If a country imports foreign equipment and owes a lot of foreign currency debt, then if its own currency depreciates, their foreign debt will be very serious.

Since economies with currency mismatches are very sensitive to exchange rate fluctuations, it is generally recommended to use futures to hedge risks.