The currency that can be widely circulated in the world is foreign exchange. For example, Peru's secret currency cannot be widely traded internationally, so it does not belong to foreign exchange. However, US dollars, Japanese yen, euros and Swiss francs (Swiss francs) can be exchanged in international financial banks.

There are certain risks in storing foreign currency. If a currency circulates abroad, its circulation rate will decrease, and the quantity in its official circulation area will also decrease. In this case, its official central bank will be forced to increase the number, which will lead to the devaluation of the currency under certain conditions. For example, in 2002, the dollar depreciated 15% against the euro in a short time, which led to the depreciation of the euro zone's dollar foreign exchange reserves.

Investors can predict the future trend by reading the news and invest in this currency through currency traders. If the facts are better than expected, the currency will appreciate and investors will make a profit.