There is ample empirical literature centering on the effectiveness of foreign exchange intervention (FXI). Given the mix of objectives and country-heterogeneity, the general lack of consensus thus far is no surprise. We shed light on this debate by conducting the first comprehensive meta-analysis in the FXI literature, with 279 reported effects that stem from 74 distinct empirical studies. We cover estimations conducted in 19 countries across five decades. Overall, our meta-survey reports an average depreciation of domestic currency of 1% and a reduction of exchange rate volatility of 0.6%, in response to a $1 billion US dollar purchase. Results are qualitatively confirmed but smaller in size under fixed and random-effect estimations. When narrowing in on different economic factors, we find that effects are magnified for cases consistent with the monetary trilemma (greater if financial openness and monetary independence are low). Effects are also larger in emerging than advanced economies, when banking crises remain mild, and when interventions are large in size and are announced.

Most of the foreign exchange intervention literature overlooks the influence of market uncertainty when evaluating effectiveness. In this paper we take a fresh new look at how this uncertainty amplifies exchange rate effects. Our contribution is twofold. We first posit a partial equilibrium model with frictions to illustrate that when uncertainty is low, intervention is less effective, for agents are willing to bet against the central bank. Conversely, when uncertainty is high, intervention faces a weaker countervailing force from speculators and arbitragers. Second, we empirically test for the incremental effects of flimsy exchange rate fundamentals by using a sharp policy discontinuity in the way the Central Bank of Colombia intervened in the FX market. Our results indicate that market uncertainty increases depreciation of domestic currency in approximately 2 percentage points (pp) following central bank purchases of foreign currency and extends its duration in up to 4 weeks. Additionally, these purchases have an incremental effect in curbing exchange rate volatility in close to 5 pp.