Stochastic skew in currency options

We analyze the behavior of over-the-counter currency option prices across moneyness, maturity, and calendar time on two of the most actively traded currency pairs over the past eight years. We find that, on any given date, the conditional risk-neutral distribution of currency returns can show strong asymmetry. This asymmetry varies greatly over time and often switches signs. We develop and estimate a class of models that captures this stochastic skew behavior. Model estimation shows that our stochastic skew models significantly outperform traditional jump-diffusion stochastic volatility models both in sample and out of sample.