Dekkingsrenteparitet

Dekkingsrenteparitet, also known as interest rate parity, is a fundamental concept in international finance that describes the relationship between interest rates and exchange rates across different countries. It asserts that, under perfect market conditions, the difference in national interest rates should be offset by the expected change in the exchange rate between two currencies. This concept ensures that there is no arbitrage opportunity for investors who seek to profit from differences in interest rates across countries.

There are two main forms of interest rate parity: covered and uncovered. Covered interest rate parity (CIRP) involves forward exchange rates and guarantees that investors cannot earn riskless profits by exploiting interest rate differentials, because a forward contract is used to hedge exchange rate risk. Uncovered interest rate parity (UIRP), on the other hand, assumes that investors form expectations about future spot exchange rates without using forward contracts, and thus, the relationship is based on expected changes in exchange rates.

The mathematical form of covered interest rate parity is expressed as: (1 + i_d) = (F/S) * (1 + i_f), where i_d and i_f are the interest rates in domestic and foreign countries, respectively, and F and S are the forward and spot exchange rates. This relationship indicates that differences in interest rates are offset by the forward premium or discount.

Interest rate parity plays a critical role in international investment and currency markets by influencing currency exchange rate movements and informing monetary policy decisions. Deviations from parity can signal arbitrage opportunities or market inefficiencies. The theory assumes freely mobile capital, perfect liquidity, and rational expectations, although real-world factors often cause deviations from strict parity conditions.