Realized FX Volatility : Statistical Properties and Applications

This paper empirically examines the statistical properties of realized volatility and the relationships between volatility and correlation measurements of realized volatility by using intraday high-frequency foreign exchange (FX) rates. Results regarding the distributional and dynamic properties of realized volatility are in agreement with the findings of previous studies. However, the positive correlation present in previous studies is not found in the case of JPY. On trading days with low volatility in the FX market, realized correlation coefficients between JPY and other currencies have positive values, while realized correlation coefficients on trading days with high volatility show negative values. These results are due to the Japanese government's intervention in the FX market, particularly during trading days with high volatility. In this regard, our results suggest that the positive relationships between volatility and correlations verified in previous studies are not a general phenomenon in the case of government intervention and government intervention may distort the efficiency of the FX market. In addition, we show that the multivariate measurement of realized volatility based on intraday high-frequency data can be a useful tool for determining the occurrence of external intervention in the FX market.