The Roles of Short-Run and Long-Run Volatility Factors in Options Market: A Term Structure Perspective
54 Pages Posted: 14 Mar 2011
Date Written: March 11, 2011
This paper examines the option pricing implications of short-run and long-run volatility factors, which are assumed to be driven by short-run and long-run news events, respectively. Using a comprehensive dataset of S&P 500 index options over 1993-2008, I find that the proposed two-factor volatility models have two desirable properties that help capture the term structures of option-implied volatility and skewness. First, the options data show evidence of time-variation in the long-run expectation of volatility, which may be caused by long-run news events. While this feature is inconsistent with a single-factor volatility assumption, the two-factor volatility models do a good job of matching the entire term structure of implied volatility. Second, the options data reveal that the term structure of implied skewness is nearly flat on average. This feature is hard to reconcile with single-factor volatility models and jumps in returns. In contrast, I find that the two-factor volatility models can generate flat term structures much like those seen in the data. In particular, the short-run volatility factor is dominant in generating short-term skewness, while the long-run volatility factor plays a pivotal role in generating long-term skewness.
Keywords: Option Pricing, Stochastic Volatility, Long-Run Volatility, Volatility Smirk, Skewness
JEL Classification: G12, G13
Suggested Citation: Suggested Citation