One of the most popular strategies related to implicit subsidies is the FX carry trade. Historically, positions in floating and convertible currencies with significant interest rate differential to the USD have benefited from two types of implicit subsidies.
- First, central banks often impose high real local short-term interest rates and engage in FX interventions, in both directions, to reduce inflation and financial uncertainty. Such policies benefit the risk-return trade-off of agents that lend in local currency and fund in foreign currency. Empirical research shows that official currency interventions can cause persistent external imbalances and over- or under-valuation of a currency (view post here). Moreover, central banks that lean against the wind of carry flows through sterilized currency interventions create what is called an “FX forward bias”, a combination of interest differential and expected currency appreciation. Both actions favor the carry trade and represent a subsidy to the market as a whole (view post here).
- Second, institutions and households that have experienced or fear financial turmoil are often willing to forgo expected return by holding “hard currencies” rather than carry currencies (view post here). Hence, they are willing to pay an implicit insurance premium. Indeed, FX carry trades have historically been most profitable when high risk premia caused both high interest rates and undervaluation (view post here). Likewise, there is evidence that high risk aversion as measured by volatility risk premia, differences between options-implied and actual volatility, leads to undershooting and subsequent outperformance of carry currencies (view post here).
FX carry opportunities depend on market structure and regulation. In emerging markets observed carry typically contains a combination of classic interest rate differential and an arbitrage premium that reflects the state of on-shore and off-shore markets (view post here). The arbitrage premium is often another form of implicit subsidy.
FX carry trades also illustrate the inherent vulnerability of subsidy-based investment strategies. Positive carry typically encourages capital inflows into small and emerging markets. This helps compressing inflation and but is also conducive to a domestic asset market boom. Because of the former, the central bank does not fight the latter. In this way FX carry strategies can produce self-validating flows. Financial markets create their own momentum. Conversely, a reversal of such flows is self-destructing (view post here).
Another implicit subsidy arises from the hedge value of currencies. Depending on circumstances, some currencies have a tendency to strengthen against the USD when global or U.S. equity prices fall. Expected negative correlation means that investors pay a premium for holding such a currency in a diversified portfolio. This preference translates into an implicit subsidy for those willing to short it on its own. Analogously, expected positive correlation of a currency with equity prices means that investors require a discount for holding that currency in a diversified portfolio, which translates into a subsidy for those willing to be long. The hedge value of a currency, as priced by the market, can be inferred directly from quanto index contracts (view post here).