Some Open Economy Macro:
The Impossible trinity
Summation of the argument (through contradiction):- Some may argue that having a fixed exchange rate policy, monetary policy & free flow of capital at the same time is a necessarily good thing.
- However, this is wrong in the view of macroeconomics, it is argued that this sort of reasoning violates the "impossible trinity" (aka policy trilemma).
- This occurs where there are three choices which the government cannot simultaneously adopt. It is argued that they should only adopt two of these three (simultaneously).
- The three choices are : Fixed exchange rates, free capital movements & setting their own interest rate.
If country A tries to choose all three at the same time, the following happens:
- If A tries to lower it's IR in order to stimulate their economy during a recession. In order to do this, they must increase the money supply which in turn decreases the IR.
However, when the IR of A is lower than that of its trading partners, everyone will want to put their money overseas due to free capital movements.
- So they sell their own currency on the foreign exchange market and buy foreign currency. However, this increases the supply of country A's currency on the foreign market, creating a downward pressure on their currency.
- Since the government of A wishes to maintain a fixed ER, it will have to sell foreign currency from it's reserves to buy back it's own currency, increasing the demand for their currency.
- However, if govt. A keeps doing this, it will run out of foreign reserves & has lost autonomy over its own interest rates.