Capital flight usually involves smuggling, corruption, tax evasion and other privately owned illegal assets, so this kind of capital is not controlled by the government. These capital outflows are difficult to predict and accurately measure.

Foreign exchange reserves have the functions of enhancing comprehensive national strength and resisting financial risks. Because capital flight can't accurately measure capital, foreign exchange reserves can't better adjust economic imbalance. The main purpose of foreign exchange reserves is to pay off the balance of payments deficit, which is often used to intervene in the foreign exchange market and maintain the exchange rate of the domestic currency.

If the foreign exchange reserves are unbalanced, it will not be able to maintain the exchange rate of the reformed currency.