No abstract

This paper investigates informed trading on stock volatility in the option market. We construct non-market maker net demand for volatility from the trading volume of individual equity options and find that this demand is informative about the future realized volatility of underlying stocks. We also find that the impact of volatility demand on option prices is positive. More importantly, the price impact increases by 40% as informational asymmetry about stock volatility intensifies in the days leading up to earnings announcements and diminishes to its normal level soon after the volatility uncertainty is resolved.THE LAST SEVERAL DECADES have witnessed astonishing growth in the market for derivatives. The market's current size of $200 trillion is more than 100 times greater than 30 years ago (Stulz (2004)). Accompanying this impressive growth in size has been an equally impressive growth in variety: The derivatives market now covers a broad spectrum of risk, including equity risk, interest rate risk, weather risk, and, most recently, credit risk and inf lation risk. This phenomenal growth in size and breadth underscores the role of derivatives in financial markets and their economic value. While financial theory has traditionally emphasized the spanning properties of derivatives and their consequent ability to improve risk-sharing (Arrow (1964) and Ross (1976)), the role of derivatives as a vehicle for the trading of informed investors has emerged as another important economic function of these securities (Black (1975) and Grossman (1977)).We contribute to the body of knowledge on the economic value of derivatives by investigating the role of options as a mechanism for trading on information about future equity volatility. Our focus on informed volatility trading is motivated to a large extent by the fact that equity options are uniquely suited to investors with information about future volatility. Unlike traders with * Ni is at the Hong Kong University of Science and Technology. Pan is at the MIT Sloan School of Management and NBER. Poteshman is at the University of Illinois at Urbana-Champaign. We thank Joe Levin, Eileen Smith, and Dick Thaler for assistance with the data used in this paper. We thank Bob Whaley and an anonymous referee for extensive and insightful comments. We also benefited from the comments of Joe Chen, Jun Liu, Neil Pearson, Josh Pollet, Rob Stambaugh (the editor), Dimitri Vayanos, Jiang Wang, Josh White, and seminar participants at the University of British Columbia, the University of Illinois at Urbana-Champaign, the University of Virginia, Vanderbilt University, and the 2006 AFA meetings. Poteshman thanks the Office for Futures and Options Research at the University of Illinois at Urbana-Champaign for financial support. We bear full responsibility for any remaining errors. 1060The Journal of Finance directional information about underlying stock prices who can trade in either the stock or option markets, traders with volatility information can only use nonlinear securities such as...

No abstract

This paper investigates informed trading on stock volatility in the option market. We construct non-market maker net demand for volatility from the trading volume of individual equity options and find that this demand is informative about the future realized volatility of underlying stocks. We also find that the impact of volatility demand on option prices is positive. More importantly, the price impact increases by 40% as informational asymmetry about stock volatility intensifies in the days leading up to earnings announcements and diminishes to its normal level soon after the volatility uncertainty is resolved. Copyright (c) 2008 by The American Finance Association.