The Black-Market Exchange Rate Versus the Official Rate: Which Rate Fosters the Adjustment Speed in the Monetarist Model?

Many less developed countries have currency controls, which can lead to black-market trade and cause distortions in the exchange market. We test the flexible-price monetary model for 25 less developed countries, using both official and black-market exchange rates. We find that the model is supported in the long run, particularly when black-market rates are used. Measuring the speed of convergence to equilibrium, we find that it is often higher in the black-market specification, implying greater efficiency. This could offer justification for exchange-rate unification, particularly in Latin America.