Solving Endogeneity in Assessing the Efficacy of Foreign Exchange Market Interventions

Sterilized foreign exchange market interventions have been suspected of being inefficient by many empirical studies, but they are plagued by endogeneity problems. To solve the problems, this paper identifies a system that depicts interactions between the interventions and the foreign exchange rate. The model shows that the interventions are effective when the interventions alter the market participants' conditional expectations of the rate without decreasing the conditional variances. This paper estimates Markov-switching type policy reaction functions by conditional MLE, and market demand/supply curves by IV estimation with generated regressors. The empirical results verify that the interventions of the Bank of Korea from 2001 to 2002 were indeed effective.