The liquidity effects associated with addition of a stock to the S&P 500 index: evidence from bid/ask spreads

This study examines changes in stock liquidity, as measured by the bid/ask spread, when a stock is added to the S&P 500 Index. The paper presents evidence of a significant decrease in the bid/ask spread upon S&P 500 addition, however, this effect is limited to only those stocks that were not trading listed options. Further, the decrease in the bid/ask spread for nonoptioned stocks is accompanied by a significant and permanent increase in share price and trading volume. While optioned stocks experience a permanent increase in trading volume, they experience only a temporary increase in share price. The findings for optioned stocks support the hypothesis that the price and volume effects associated with S&P 500 addition derive from temporary price pressure. Findings pertaining to the nonoptioned stocks indicate that the price and volume effects associated with S&P addition reflect enhanced stock liquidity. The decrease in the bid/ask spread for nonoptioned stocks is attributed to informational efficiencies achieved via index arbitrage trading, and it is argued that this effect is mitigated for optioned stocks due to the pre-existence of arbitrage trading between the option and the underlying stock.     

Average correlation and stock market returns

If the Roll critique is important, changes in the variance of the stock market may be only weakly related to changes in aggregate risk and subsequent stock market excess returns. However, since individual stock returns share a common sensitivity to true market return shocks, higher aggregate risk can be revealed by higher correlation between stocks. In addition, a change in stock market variance that leaves aggregate risk unchanged can have a zero or even negative effect on the stock market risk premium. We show that the average correlation between daily stock returns predicts subsequent quarterly stock market excess returns. We also show that changes in stock market risk holding average correlation constant can be interpreted as changes in the average variance of individual stocks. Such changes have a negative relation with future stock market excess returns.     

The Impact of Option Introduction on Stock Return Variances: The Role of Bid-Ask Spreads, Return Autocorrelations, and Intrinsic Variances

The purpose of this paper is to examine changes in stock return variances following option introduction. The sample consists of National Market System stocks and employs both transaction returns and returns based on bid and ask quotes. Variances are decomposed into portions attributable to bid-ask spreads, return autocorrelations, and intrinsic variances. Spreads play a negligible role in explaining variance changes. A generally positive component to short-term autocorrelations falls following option introduction, increasing variances over short holding periods. Intrinsic variances fall prior to the October 1987 crash, but do not change after the crash with option introduction.     

What Is the Expected Return on a Stock?

We derive a formula for the expected return on a stock in terms of the risk‐neutral variance of the market and the stock's excess risk‐neutral variance relative to that of the average stock. These quantities can be computed from index and stock option prices; the formula has no free parameters. The theory performs well empirically both in and out of sample. Our results suggest that there is considerably more variation in expected returns, over time and across stocks, than has previously been acknowledged.     

The information content of stock split announcements: Do options matter?

We provide a new test of the informational efficiency of trading in stock options in the context of stock split announcements. These announcements tend to be associated with positive abnormal returns. Our traditional event study results show abnormal returns that are significantly lower for optioned than non-optioned stocks, whether traded on the NYSE, Amex, or Nasdaq. After controlling for market returns, capitalization, book-to-market ratio, and trading volume, we find that the abnormal returns are significantly lower for NYSE/Amex optioned than non-optioned stocks. Although the results for Nasdaq stocks are not as clear, the overall effects tend to be lower after optioning. These findings are consistent with the hypothesis that the prices of optioned stocks embody more information, diminishing the impact of the stock split announcement. They provide new evidence of the beneficial effects of options on their underlying stocks.     

DEALER BID-ASK SPREADS AND OPTIONS TRADING ON OVER-THE-COUNTER STOCKS

In this study the impact of option listings on bid-ask spreads for over-the-counter stocks is examined. Option listings are hypothesized to impact spreads by affecting the inventory-holding cost and/or the informed risk component of spreads. Univariate tests reveal that the commencement of options trading is accompanied by a statistically significant decline in percentage spreads. In addition, it is found that there is a significant rise in the average daily stock trading volume in the post-option-listing period, while there is no significant change in variance of the underlying stock returns in the short term. Regression results indicate that some stocks experience a decline in spreads even after controlling for changes in inventory-holding costs. The univariate and regression results taken in conjunction indicate a favorable impact of option listings on both the inventory-holding cost and informed-trading risk components of spread determinants. The combined evidence suggests that initiation of options trading enhances the overall liquidity of the underlying stock.     

The effect of CBOE option listing on the volatility of NYSE traded stocks: a time-varying variance approach

This paper employs the standard General Auto-regressive Conditional Heteroskedasticity (GARCH(1,1)) process to examine the impact of option listing on volatility the underlying stocks. It takes into consideration the time variation in the individual stock's variance and explicitly tests whether option listing causes any permanent volatility change. It also investigates the impact of option listing on the speed at which information is incorporated into the stock price. The study uses clean samples to avoid sample selection biases and control samples to account for the change in the volatility and/or information flows that may be caused by factors other than option listing.     

The comovement of option listed stocks

This study examines the changes in return comovement around the listing and delisting of stock option contracts. We show that newly option listed stocks experience an increase in comovement with a portfolio of option listed stocks and a decrease in comovement with the portfolio of non-optioned stocks. Similarly, stocks that undergo option delisting exhibit a decrease in comovement with option listed stocks and an increase in comovement with non-optioned stocks. We verify the reliability of our findings in several ways. A matched sample analysis suggests that our results are not driven by factors other than option listing and we find similar results using a calendar-time approach. Further analysis reveals that commonalities in option trading may induce the comovement in the option listed stocks. Overall, our evidence is consistent with the predictions of the category or habitat view of comovement.     

Idiosyncratic Risk Matters!

This paper takes a new look at the predictability of stock market returns with risk measures. We find a significant positive relation between average stock variance (largely idiosyncratic) and the return on the market. In contrast, the variance of the market has no forecasting power for the market return. These relations persist after we control for macroeconomic variables known to forecast the stock market. The evidence is consistent with models of time‐varying risk premia based on background risk and investor heterogeneity. Alternatively, our findings can be justified by the option value of equity in the capital structure of the firms.     

The Effect of Executive Stock Option Plans on Stockholders and Bondholders

Executive stock option plans have asymmetric payoffs that could induce managers to take on more risk. Evidence from traded call options and stock return data supports this notion. Implicit share price variance, computed from the Black-Scholes option pricing model, and stock return variance increase after the approval of an executive stock option plan. The event is accompanied by a significant positive stock and a negative bond market reaction. This evidence is consistent with the notion that executive stock options may induce a wealth transfer from bondholders to stockholders.     

Index Futures Trading and Stock Return Volatility: Evidence from the Introduction of Mid Cap 400 Index Futures

The MidCap 400 stock index is used to provide new evidence on the relation between stock index futures trading and stock return volatility. The study documents a significant decrease in return volatility and systematic risk, and a significant increase in trading volume for the MidCap 400 stocks after the introduction of the MidCap index. A control sample of medium-capitalization stocks, however, exhibits similar contemporaneous changes in these measures. The MidCap stocks and the control stocks also experience a significant decrease in volatility and an increase in volume after the introduction of MidCap 400 index futures. Thus, the study finds no difference in the behavior of the MidCap 400 stocks and the control stocks and no evidence of a relation between index futures trading and volatility in the stock market.     

Firm life expectancy and the heterogeneity of the book-to-market effect

I argue that the reason the book-to-market effect is stronger in small stocks is because smaller stocks generally have shorter life expectancy and therefore shorter equity duration. I build a model in which the book-to-market effect is stronger in stocks with shorter life expectancy. Empirically, I use delisting probability as my proxy for life expectancy. The data support my model's central prediction and its additional implications for stock return and variance. My results provide a rational explanation for the heterogeneity of the book-to-market effect, evidence previously taken as support for behavioral explanations.     

Relation between time-series and cross-sectional effects of idiosyncratic variance on stock returns

Consistent with the post-1962 US evidence by Ang et al. [Ang, A., Hodrick, R., Xing Y., Zhang, X., 2006. The cross-section of volatility and expected returns. Journal of Finance 51, 259–299], we find that stocks with high idiosyncratic variance (IV) have low CAPM-adjusted expected returns in both pre-1962 US and modern G7 data. We also test in three ways the conjecture that IV is a proxy of systematic risk. First, the return difference between low and high IV stocks – that we dub as IVF – is a priced factor in the cross-section of stock returns. Second, loadings on lagged market variance and lagged average IV account for a significant portion of variation in average returns on portfolios sorted by IV. Third, the variance of IVF correlates closely with average IV, and the two variables have similar explanatory power for the time-series and cross-sectional stock returns.     

Complete markets,informed trading and equity option introductions

This paper proposes and tests a new hypothesis concerning the price impact of option introductions on the underlying asset. We argue that the leverage properties of options induce a higher level of informed trading in the aggregate market (underlying plus derivative), resulting in excess listing-day price movements in the newly optioned equity. Using an alternative dataset, our results suggest that this may be an explanation for the observed positive than negative excess listing-day returns of US optioned stocks over the past thirty years.     

Stock price clustering on option expiration dates

This paper presents striking evidence that option trading changes the prices of underlying stocks. In particular, we show that on expiration dates the closing prices of stocks with listed options cluster at option strike prices. On each expiration date, the returns of optionable stocks are altered by an average of at least 16.5 basis points, which translates into aggregate market capitalization shifts on the order of $9 billion. We provide evidence that hedge rebalancing by option market makers and stock price manipulation by firm proprietary traders contribute to the clustering.     

Cross-section of option returns and volatility

We study the cross-section of stock option returns by sorting stocks on the difference between historical realized volatility and at-the-money implied volatility. We find that a zero-cost trading strategy that is long (short) in the portfolio with a large positive (negative) difference between these two volatility measures produces an economically and statistically significant average monthly return. The results are robust to different market conditions, to stock risks-characteristics, to various industry groupings, to option liquidity characteristics, and are not explained by usual risk factor models.     

Option trading after the opening bell and intraday stock return predictability

Prior literature finds that information is reflected in option markets before stock markets, but no study has explored whether option volume soon after market open has predictive power for intraday stock returns. Using novel intraday signed option-to-stock volume data, we find that a composite option trading score (OTS) in the first 30 min of market open predicts stock returns during the rest of the trading day. Such return predictability is greater for smaller stocks, stocks with higher idiosyncratic volatility, and stocks with higher bid–ask spreads relative to their options’ bid–ask spreads. Moreover, OTS is a significantly stronger predictor of intraday stock returns after overnight earnings announcements. The evidence suggests that option trading in the 30 min after the opening bell has predictive power for intraday stock returns.     

Evidence of the Nostationarity of the Variance Rate of Return of New York Stock Exchange Listed Common Stock

The variance rate of return is shown to be nonstationary for the majority of stocks studied, with a median change of 100 percent over a period of one and one-half years. The degree of change declines as the interval between estimates is shortened as does the extent to which the variance rates of different of the change do not appear to be strongly related to the trading frequency of the stock.     

The market price of risk of the variance term structure

In this paper I examine the market price of risk of the variance term structure. To this end, the S&P 500 option implied variance term structure is used as a proxy for aggregate variance risk. Principal component analysis shows that time variation in the variance term structure over the 1996–2012 period can be explained mainly by two factors which capture changes in the level and slope. The market price of risk of each factor is estimated in the cross-section of stock returns. The slope of the variance term structure is the most significant factor in the cross-section of stocks returns and carries a negative risk premium. The slope factor has also some predictive ability over long horizon equity returns.     

Measurement effects and the variance of returns after stock splits and stock dividends

This article examines the relation between two factors affectingstock returns, the bid-ask spread and price discreteness, andthe increase in return variance after ex-dates of stock splitsand stock dividends. Controlling for these effects, the varianceof daily returns still increases significantly. The varianceof weekly returns also increases significantly, and the varianceof returns for a control sample of nonsplitting firms showsno significant increase. Variance ratio tests show that bid-askerrors are small for these stocks and therefore cannot explainthe large increase in variance. Spreads and price discretenessdo not explain increased variance after stock distributions.