Leverage effect breakdowns and flight from risky assets

Abstract

Though part of ‘market lore’, in 1976 Black first reported the inverse relationship between price and volatility, calling it the ‘leverage effect’. Without providing evidence, in 1988 Black claimed that in the months leading up to the October 1987 crash the relationship changed: price and volatility both rose. Using daily data for the Old VIX, derived from S&P 100 Index option market prices, to estimate intra-quarterly regressions of implied volatility against price from Q2 1986 to Q1 2012, the author verifies Black’s claim for the October 1987 crash, and interestingly, for subsequent periods of crisis. He then analyses several constant-elasticity-of-variance optimal portfolio rules, which include the leverage effect, to show the elasticity sign switch implies that investors reduce their risky asset holdings to zero.