The dollar carry trade, like the old-fashioned carry trade, is a risky strategy. The dollar carry trade, which historically fed on relatively high cash rates, is currently feeding on expectations of higher cash rates. Hence, much like a momentum strategy, its recent success has largely come from an appreciating dollar. But the strengthening of the dollar has not been accompanied by higher short rates.3 In this environment, it is understandable that the dovish attitude of some Fed officials has recently spooked the markets and slowed down the dollar’s rise.4
In addition, U.S. investors who are selling foreign currencies are increasing their exposure to the risk of an economic slowdown in the United States. Hence, they are failing to diversify the macroeconomic risk that tends to hurt their income the most. In the medium and long run, as value strategies become more important in the currency markets, they may find themselves vulnerable to a weakening dollar and slower domestic growth.
The first risk, then, is that future U.S. interest rates might disappoint consensus expectations (Shepherd, 2015). Currency prices are forward looking, and by now they should already incorporate expectations of higher interest rates in the United States and of QE in Europe and Japan. Any further dollar appreciation should come either from an unexpectedly hawkish Federal Reserve stance or unexpectedly loose foreign policies. However, several signals suggest that Fed monetary policy might actually remain highly accommodative in the months to come. Recognizing that a stronger dollar might harm the economic recovery, some Fed officials appear to have misgivings about raising interest rates too soon or too far.
More generally, investors should be aware that momentum positions characteristically have rather short lives. By construction, currency momentum strategies have taken advantage of relatively transitory trends in foreign exchange movements. In comparison, carry trade strategies have typically exploited cash rate differentials that persisted over an extended period of time. The historical record suggests that, without positive surprises from the U.S. economy, the ongoing appreciation of the dollar might soon come to an end.
The second risk arises from the current price of the U.S. dollar. It appears to be overvalued with respect to the currencies of the United States’ major trading partners. Figure 2 illustrates that the U.S. dollar is more than 10% above its long-run equilibrium value as predicted by a simple application of the Purchasing Power Parity (PPP) theory.5 Given that higher valuations have generally been supported by higher interest rates, the current overvaluation might prove unsustainable in the medium term. The official U.S. unemployment rate is, at 5.5%, about 25–50 bps above its estimated equilibrium level, while core inflation is not far from its 2% target. Hence, it appears that permanently low interest rates are consistent with a U.S. economy running at the speed desired by the Fed.