The foreign currency, gold and other important assets, kept in the central bank of any country are called the reserves of foreign exchange.
Foreign-exchange reserves (also called forex reserves or FX reserves) is money or other assets held by a central bank or other monetary authority so that it can pay its liabilities if needed, such as the currency issued by the central bank, as well as the various bank reserves deposited with the central bank by the government and other financial institutions.[1] Reserves are held in one or more reserve currencies, mostly the United States dollar and to a lesser extent the Euro
In a strict sense, foreign-exchange reserves should only include foreign banknotes, foreign bank deposits, foreign treasury bills, and short and long-term foreign government securities.[2] However, the term in popular usage also adds gold reserves, special drawing rights (SDRs), and International Monetary Fund (IMF) reserve positions. This broader figure is more readily available, but it is more accurately termed official international reserves or international reserves.
Foreign-exchange reserves are called reserve assets in the balance of payments and are located in the capital account. Hence, they are usually an important part of the international investment position of a country. The reserves are labeled as reserve assets under assets by functional category. In terms of financial assets classifications, the reserve assets can be classified as Gold bullion, Unallocated gold accounts, Special drawing rights, currency, Reserve position in the IMF, interbank position, other transferable deposits, other deposits, debt securities, loans, equity (listed and unlisted), investment fund shares and financial derivatives, such as forward contracts and options. There is no counterpart for reserve assets in liabilities of the International Investment Position. Usually, when the monetary authority of a country has some kind of liability, this will be included in other categories, such as Other Investments. [3] In the Central Bank’s Balance Sheet, foreign exchange reserves are assets, along with domestic credit.
Official international reserves assets allow a central bank to purchase the domestic currency, which is considered a liability for the central bank (since it prints the money or fiat currency as IOUs). Thus, the quantity of foreign exchange reserves can change as a central bank implements monetary policy,[4] but this dynamic should be analyzed generally in the context of the level of capital mobility, the exchange rate regime and other factors. This is known as Trilemma or Impossible trinity. Hence, in a world of perfect capital mobility, a country with fixed exchange rate would not be able to execute an independent monetary policy.
A central bank that implements a fixed exchange rate policy may face a situation where supply and demand would tend to push the value of the currency lower or higher (an increase in demand for the currency would tend to push its value higher, and a decrease lower) and thus the central bank would have to use reserves to maintain its fixed exchange rate. Under perfect capital mobility, the change in reserves is a temporary measure, since the fixed exchange rate attaches the domestic monetary policy to that of the country of the base currency. Hence, in the long term, the monetary policy has to be adjusted in order to be compatible with that of the country of the base currency. Without that, the country will experience outflows or inflows of capital. Fixed pegs were usually used as a form of monetary policy, since attaching the domestic currency to a currency of a country with lower levels of inflation should usually assure convergence of prices