The Optimal Level Of International Reserves For Emerging Market Countries

We present a model of the optimal level of international reserves for a small open economy that is vulnerable to sudden stops in capital flows. Reserves allow the country to smooth domestic absorption in response to sudden stops, but yield a lower return than the interest rate on the country's long-term debt. We derive a formula for the optimal level of reserves, and show that plausible calibrations can explain reserves of the order of magnitude observed in many emerging market countries. However, the recent buildup of reserves in Asia seems in excess of what would be implied by an insurance motive against sudden stops.

Two striking facts about international capital flows in emerging economies motivate this paper: (1) Governments hold large amounts of international reserves, for which they obtain a return lower than their borrowing cost. (2) Purchases of domestic assets by nonresidents and purchases of foreign assets by residents are both procyclical and collapse during crises. We propose a dynamic model of endogenous default that can account for these facts. The government faces a trade-off between the benefits of keeping reserves as a buffer against rollover risk and the cost of having larger gross debt positions. Long-duration bonds, the countercyclical default premium, and sudden stops are important for the quantitative success of the model.

Using panel data for 15 economies from 2001-12, I identify determinants of central bank foreign exchange intervention in emerging markets (“EMs”) with flexible to moderately managed exchange rates. Similar to other studies, I find that central banks tend to “lean against the wind,” buying/selling more foreign exchange in response to greater short-run and medium-run appreciation/depreciation pressures. The panel structure provides a framework to test whether other macroeconomic variables influence the different rates of reserve accumulation between economies. In testing other variables, I find evidence of both precautionary and external competitiveness motives for reserve accumulation.

This paper analyzes reserve adequacy in emerging market countries. It argues that the old rule of thumb of maintaining reserves equivalent to three months of imports has become obsolete and that, instead, a new benchmark is needed which takes into account the increased importance of capital flows. The paper suggests such a benchmark, consisting of the sum of short-term debt on a residual maturity basis (the external drain) and an allowance for possible capital flight (the internal drain), taking into account differences in country risk and exchange rate regime.

Why do countries hold so much international reserves? Global reserve holdings (excluding gold) were equivalent to 17 weeks of imports at the end of 1999. That is almost double what they were at the end of 1960 and about 20 percent higher than they were at the start of the 1990s. In this paper we study countries’ reserve holdings in light of both the increased financial volatility experienced in the last decade and diminished adherence to fixed exchange rates. We find that buffer-stock reserve models work about as well in the modern floating-rate period as they did during the Bretton Woods regime. During both periods, however, the models’ fundamentals explain only a small portion (10-15 percent) of reserves volatility.

Tiivistelmä.

Why have emerging market economies (EMEs) been stockpiling international reserves? We find that motives have varied over time?vulnerability to current account shocks was relatively important in the 1980s but, as EMEs have become more financially integrated, factors related to the magnitude of potential capital outflows have gained in importance. Reserve accumulation as a by-product of undervalued currencies has also become more important since the Asian crisis. Correspondingly, using quantile regressions, we find that the reason for holding reserves varies according to the country's position in the global reserves distribution. High reserve holders, who tend to be more financially integrated, are motivated by insurance against capital account rather than current account shocks, and are more sensitive to the cost of holding reserves than are low-reserve holders. Currency undervaluation is a significant determinant across the reserves distribution, albeit for different reasons.