Volatility Effects

Implied idiosyncratic volatility is the “investor fear gauge” or perceived risk for an individual stock based on the pricing of its associated options, as contrasted with: (1) overall stock market volatility as measured by variables such as the CBOE Volatility Index (VIX); and, (2) realized idiosyncratic volatility based on variation of the stock’s historical price. Can investors use the return due this perceived risk in an individual stock as a building block in constructing outperforming portfolios? In their December 2006 paper entitled “Idiosyncratic Implied Volatility and the Cross-Section of Stock Returns”, Dean Diavatopoulos, James Doran and David Peterson examine the relationship between idiosyncratic implied volatility and 30-day, 60-day and 91-day future returns for different kinds of equities. Using daily data on 240 stocks with actively traded options for the period January 1996 to June 2005, they find that: Keep Reading

Are there systematic errors in market expectations about the future volatilities of individual stock prices? If so, what reliable strategy could a trader use to exploit these errors? In their August 2006 paper entitled “Option Returns and the Cross-Sectional Predictability of Implied Volatility”, Amit Goyal and Alessio Saretto examine the complete range of implied stock price volatilities for all U.S. equity options to devise an volatility forecasting model more efficient than that inherent in the market. They then test the model’s ability (out of sample) to identify outperforming options trading strategies that exploit this market inefficiency. Using daily data for all U.S. equity options over the period January 1996 to May 2005, they conclude that: Keep Reading

Does a willingness to pay more or less for options than indicated by recent actual levels of stock return volatility reflect the current level of investor/trader risk aversion? In other words, does the gap between option-implied and historical stock return volatilities provide a tradable measure of fearfulness? In the September 2006 draft of their paper entitled “Expected Stock Returns and Variance Risk Premia”, Tim Bollerslev, George Tauchen and Hao Zhou investigate the predictive power of the implied-historical volatility gap for future stock returns. Using monthly data for the S&P 500 index (VIX for implied volatility and a summation of five-minute squared returns for historical volatility) for the period 1990-2005, they find that: Keep Reading

Do short sellers avoid highly volatile stocks, and thereby leave them overvalued? If so, when short sellers do attack volatile stocks, is the level of overvaluation therefore compelling? In the August 2006 update of their paper entitled “Costly Arbitrage and Idiosyncratic Risk: Evidence from Short Sellers”, Ying Duan, Gang Hu and David McLean test the hypothesis that short sellers tend to avoid stocks with high idiosyncratic risk because of the high cost of hedging such risk. Using data for stock prices, short interest levels and other factors spanning 1988-2003, they find that: Keep Reading

Can you trade on the CBOE Volatility Index (VIX), the “investor fear gauge,” or not? If so, what should you trade and should your trades be short-term or long-term? In their September 2005 paper entitled “VIX Signaled Switching for Style-Differential and Size-Differential Short-term Stock Investing”, Dean Leistikow and Susana Yu test the usefulness of VIX level as a signal for short-term switching between: (1) value and growth stock indexes; and, (2) small-capitalization and large-capitalization stock indexes. They note that “…VIX can be viewed as a market-determined forecast of short-term market volatility that, by construction, has a constant one-month forecast horizon.” They determine signals according to whether VIX is high or low compared to its 75-day moving average. They examine index returns for 1 day and 5 days after a VIX signal. Using data for the VIX and for various Standard & Poor’s and Russell stock indexes from the early 1990s through 2004, they find that: Keep Reading

Conventional wisdom holds that: (1) risk begets reward; and, (2) volatility is a manifestation of risk. Exceptionally high volatility in individual stock prices should, therefore, indicate future excess returns in those stocks. In their May 2006 paper entitled “The Relation between Time-Series and Cross-Sectional Effects of Idiosyncratic Variance on Stock Returns in G7 Countries”, Hui Guo and Robert Savickas investigate why the realized idiosyncratic volatility (beta) of individual stocks correlates negatively with future returns — why there is a penalty instead of a reward for this apparent risk. Using two sets of U.S. data (1926-2005 and 1963-2005) and one set of international data (1973-2003), they conclude that: Keep Reading

Implied volatility, represented by the CBOE Volatility Index (VIX), incorporates the bets of speculators on future stock market behavior. In the April 2006 revision of their paper entitled “Implied Volatility and Future Portfolio Returns”, Prithviraj Banerjee, James Doran and David Peterson examine whether the predictive power of VIX applies to specific portfolio characteristics (value versus growth, small versus large and beta) and whether variations in VIX with respect to its short-term mean are predictive. Using data from June 1986 through June 2005 and future return periods of 22 and 44 trading days, they find that: Keep Reading

Conventional wisdom holds that high (low) overall stock market volatility forecasts high (low) stock returns, as a fundamental reward-for-risk phenomenon. In their March 2006 paper entitled “Understanding Stock Return Predictability”, Hui Guo and Robert Savickas investigate a refinement to volatility-based prediction of stock market returns by combining the effects of realized overall market volatility and the average realized idiosyncratic volatility of individual stocks. They theorize that: (1) overall stock market volatility reflects the volatilities of both cash flow shocks and discount rate shocks; (2) overall stock market volatility overstates discount rate shock volatility; and, (3) average idiosyncratic volatility, which reflects the volatility of discount rate shocks only, corrects this overstatement. Using quarterly overall and idiosyncratic volatilities from 1927 through 2005, they conclude that: Keep Reading

We have selected for retrospective review a few all-time “best selling” research papers of the past few years from the General Financial Markets category of the Social Science Research Network (SSRN). Here we summarize the February 1999 paper entitled “Daily Momentum And Contrarian Behavior Of Index Fund Investors” (download count almost 1,900) by William Goetzmann and Massimo Massa. The authors investigate the existence and profitability of momentum and contrarian behaviors for stock index trading. They classify return momentum investors (trend followers) as those who buy (sell) when the market rises (drops) in the previous trading session, and return contrarian investors as “profit takers” who sell (buy) when the market rises (drops). They also examine investor response to changes in market volatility, defining both volatility momentum traders (risk chasers) and volatility contrarian traders (risk avoiders). Using daily activity records for 91,000 accounts trading an S&P 500 index during 1997 and 1998, the authors find that: Keep Reading

The market rewards investors for taking risk. Right? High volatility means high risk. Right? High volatility therefore means excess return. Right? In their January 2006 paper entitled “High Idiosyncratic Volatility and Low Returns: International and Further U.S. Evidence”, Andrew Ang, Robert Hodrick, Yuhang Xing and Xiaoyan Zhang test the relationship between past idiosyncratic volatility and future returns for stocks in developed markets around the world. Using data from 23 countries mostly over the period January 1980 through December 2003, they find that: Keep Reading