When Purchasing Power Parity (PPP) Theory applies to product markets, Interest Rate Parity (IRP) condition applies to financial markets. Interest Rate Parity (IRP) theory postulates that the forward rate differential in the exchange rate of two currencies would equal the interest rate differential between the two countries. Thus it holds that the forward premium or discount for one currency relative to another should be equal to the ratio of nominal interest rate on securities of equal risk (and duration) denominated in two currencies. For example, where the interest rate in India and US are respectively 10% and 6% and the dollar-rupees spot exchange rate is Rs.42.50/US $. The 90 day forward exchange rate would be calculated as per IRP as follows: = 42.50 (1+0.10/4)/(1+0.06/4) = Rs.42.9250 And hence, the forward rate differential [forward premium (p)] will be; (42.9250 — 42.50)/42.50 = 1% And the interest rate differential will be; Continue reading