Time-Varying Crash Risk Embedded in Index Options: The Role of Stock Market Liquidity

We estimate a continuous-time model with dynamic crash probability using the S&P500 index options and high-frequency information. We find that market illiquidity is an important factor in explaining the time-varying stock market crash risk embedded in index options. While market illiquidity and return volatility play complementary roles in explaining the time-varying crash risk, the relative contribution of the volatility factor is weakened once we include market illiquidity as an economic variable. Examining the link between market illiquidity and option-implied crash risk, we find that the availability of arbitrage capital and adverse selection facing liquidity providers are economic driving forces.