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Abstract:
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 re-balancing by option market-makers and stock price manipulation by firm proprietary traders contribute to the clustering.

Stock price clustering, Option expiration, Hedging, Manipulation

Abstract:
We find strong evidence of information transmission from the options market to underlying stock prices. Taking advantage of a unique dataset from the Chicago Board Options Exchange, we construct put to call volume ratios for underlying stocks, using only volume initiated by buyers to open new positions. Performing daily cross-sectional analyses from 1990 to 2001, we find that buying stocks with low put/call ratios and selling stocks with high put/call ratios generates an expected return of 40 basis points per day and 1 percent per week. This result is present during each year of our sample period, and is not affected by the exclusion of earnings announcement windows. Moreover, the result is stronger for smaller stocks, indicating that the options market may be a more important avenue for information transmission for stocks with less efficient information flow. Our analysis also sheds light on the type of investor behind the informed option trading. Specifically, we find that option trading from customers of full service brokers provides the strongest predictability, while that from firm proprietary traders is not informative. Furthermore, our analysis shows that while public customers on average trade in the options market as contrarians -- buying fresh new puts on stocks that have done well and calls on stocks that have done poorly, firm proprietary traders exhibit the opposite behavior. Finally, in contrast to the equity options market, we do not find any evidence of informed trading in the index options market.

options, information, volume, derivatives

Abstract:
This paper investigates options market reaction to changes in the instantaneous variance of the underlying asset. There are three main findings. First, options market investors underreact to individual daily changes in instantaneous variance. Second, these same investors overreact to periods of mostly increasing or mostly decreasing daily changes in instantaneous variance. Third, they tend to underreact (overreact) to current daily changes in instantaneous variance that are preceded mostly by daily changes of the opposite (same) sign. The third finding can reconcile the first two and is also consistent with well-established cognitive biases.

Misreaction, Behavioral Finance, Option Pricing, Stochastic Variance

Abstract:
This paper investigates the response of option market investors to the information contained in daily changes in the instantaneous variance of the underlying asset. Evidence is provided that these investors exhibit (1) short-horizon underreaction to daily information, (2) long-horizon overreaction to extended periods of mostly similar daily information, and (3) increasing misreaction (along a scale that ascends from underreaction to overreaction) to daily information as a function of the quantity of previous similar information. The increasing misreaction can reconcile the short-horizon underreaction with the long-horizon overreaction and is also consistent with well-established cognitive biases.

Underreaction, Overreaction, Behavioral Finance, Option Pricing, Stochastic Variance

Abstract:
This paper examines optimal capital structure choice using a dynamic capital structure model that is calibrated to reflect actual firm characteristics. The model uses contingent-claim methods to value interest tax shields, allows for reorganization in bankruptcy, and maintains a long-run target debt/equity ratio by refinancing maturing debt. Using this model we calculate optimal capital structures in a realistic representation of the traditional tradeoff' model. In contrast to previous research, the resulting optimal capital structures do not imply that firms tend to use too little leverage in practice. We also estimate the costs borne by a firm whose capital structure deviates from its optimal, target' debt/equity ratio. The costs of moderate deviations are relatively small, suggesting that a policy of adjusting leverage only when it deviates substantially from a target debt/equity ratio is likely to be reasonable for most firms.

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Abstract:
This paper examines optimal capital structure choice using a dynamic capital structure model that is calibrated to reflect actual firm characteristics. The model uses contingent-claim methods to value interest tax shields, allows for reorganization in bankruptcy, and maintains a long-run target debt/equity ratio by refinancing maturing debt. Using this model we calculate optimal capital structures in a realistic representation of the traditional 'tradeoff' model. In contrast to previous research, the resulting optimal capital structures do not imply that firms tend to use too little leverage in practice. We also estimate the costs borne by a firm whose capital structure deviates from its optimal, 'target' debt/equity ratio. The costs of moderate deviations are relatively small, suggesting that a policy of adjusting leverage only when it deviates substantially from a target debt/equity ratio is likely to be reasonable for most firms.

optimal capital structure, taxes, bankruptcy costs, calibration

Abstract:
Evidence exists that option prices produce biased forecasts of future volatility across a wide variety of options markets. This paper presents two main results. First, approximately half of the forecasting bias in the S&P 500 index (SPX) options market is eliminated by constructing measures of realized volatility from five minute observations on SPX futures rather than from daily closing SPX levels. Second, much of the remaining forecasting bias is eliminated by employing an option pricing model that permits a non-zero market price of volatility risk.

Abstract:
This paper analyzes the early exercise of exchange-traded options by different classes of investors over the 1996 to 1999 period. A large number of exercises are identified as clearly irrational without invoking any model of market equilibrium. Customers of discount brokers and customers of full-service brokers both engage in a significant number of irrational exercises while traders at large investment houses exhibit no irrational early exercise behavior. Rational and irrational exercise is triggered for discount and full-service customers by the underlying stock price attaining its highest level over the past year and by high returns on the underlying stock.

Abstract:
This paper analyzes the early exercise of Chicago Board Options Exchange listed calls by different classes of investors over the 1996-1999 period. We present two main findings. First, there are a large number of early exercises that can be identified as clearly irrational without invoking any model of market equilibrium, and these exercises are not uniformly distributed across the investor classes. Customers of discount brokers and customers of full service brokers both engage in a significant number of irrational exercises while traders at large investment houses exhibit no irrational early exercise behavior. Second, irrational exercise is triggered both by the underlying stock price attaining its highest level over the past year and by the underlying stock having high past returns. Our findings provide evidence that prospect theory is operative in the options market and that it applies differentially across various classes of investors.

Market Efficiency, Behavioral Finance, Early Exercise, Irrational Behavior, Prospect Theory

Abstract:
We create a dynamic model in which a self-interested, risk-averse manager makes corporate investment decisions at a levered firm with characteristics typical of public US firms. We examine the magnitude of distortions in those decisions when a new project changes firm risk and find expected changes in the values of future tax shields and bankruptcy costs to be important factors. We evaluate the extent to which these distortions vary with firm leverage, debt duration, project size, managerial risk aversion, managerial non-firm wealth, and the structure of management compensation packages.

Abstract:
This paper examines distortions in corporate investment decisions when a new project changes firm risk. It presents a dynamic model in which a self-interested, risk-averse manager makes investment decisions at a levered firm. The model, calibrated using data from public firms, is used to estimate the magnitude of distortions in investment decisions. Despite potential wealth transfers from debtholders, managers compensated with equity prefer safe projects to risky ones. Important factors in this decision are the expected changes in the values of future tax shields and bankruptcy costs when firm risk changes. We also evaluate the extent to which this effect varies with firm leverage, managerial risk aversion, managerial non-firm wealth, project size, debt duration, and the structure of management compensation packages.

Abstract:
This paper examines distortions in corporate investment decisions when a new project changes firm risk. It presents a dynamic model in which a self-interested, risk-averse manager makes investment decisions at a levered firm. The model, calibrated using data from public firms, is used to estimate the magnitude of distortions in investment decisions. Despite potential wealth transfers from debtholders, managers compensated with equity prefer safe projects to risky ones. Important factors in this decision are the expected changes in the values of future tax shields and bankruptcy costs when firm risk changes. We also evaluate the extent to which this effect varies with firm leverage, managerial risk aversion, managerial non-firm wealth, project size, debt duration, and the structure of management compensation packages.

Agency Costs, Capital Structure, Calibration

Abstract:
The question of whether and to what extent option trading impacts underlying stock prices has been a focus of intense interest since options began exchange-based trading in 1973. Despite considerable effort, no convincing evidence for a pervasive impact has been produced. A recent strand of theoretical literature predicts that rebalancing by traders who hedge their option positions increases (decreases) underlying stock return volatility when these traders have net written (purchased) option positions. This paper tests this prediction and finds a statistically and economically significant negative relationship between stock return volatility and net purchased option positions of investors who are likely to hedge. Hence, we provide the first evidence for a substantial and pervasive influence of option trading on stock prices.

options, stock price paths, impact, trading, hedging

Abstract:
This paper investigates informed trading on stock volatility in the option market. Using a unique data set from the Chicago Board Options Exchange, we construct non-market maker net demand for stock volatility from the trading volume of individual equity options. We find that this volatility demand is informative about the future realized volatility of underlying stocks which suggests the presence of volatility information traders in the option market. We also examine asset pricing implications of volatility information trading by measuring Kyle's lambda: The impact on option prices for each unit increase in volatility demand. The price impact is positive which is consistent with the existence of informational asymmetry about stock volatility. More importantly, we link the time variation in the price impact to the time variation in the degree of informational asymmetry. In particular, the price impact increases by over 50 percent 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.

options, derivatives, information, volatility

Abstract:
After the terrorist attacks of September 11, 2001 there was a great deal of speculation that the terrorists or their associates had traded in the options market on advanced knowledge of the impending events. It is nearly impossible, however, to assess the options market trading leading up to this or any other event in the absence of systematic information about the characteristics of options market activity. This paper provides this information by computing the distributions of certain options market volume ratios and put and call trading indicators both unconditionally and when conditioning on the overall level of options activity, the return and trading volume on the underlying stocks, and the return on the overall market. When the options market activity in the days leading up to the terrorist attacks is compared to the benchmark distributions, the volume ratios and call volume indicator are seen to be at typical levels but the put volume indicator appears to be unusually high.

terrorism, options, unusual trading

Abstract:
We model the demand-pressure effect on prices when options cannot be perfectly hedged. The model shows that demand pressure in one option contract increases its price by an amount proportional to the variance of the unhedgeable part of the option. Similarly, the demand pressure increases the price of any other option by an amount proportional to the covariance of their unhedgeable parts. Empirically, we identify aggregate positions of dealers and end users using a unique dataset, and show that demand-pressure effects contribute to well-known option-pricing puzzles. Indeed, time-series tests show that demand helps explain the overall expensiveness and skew patterns of both index options and single-stock options.

Option, demand, valuation, intermediation, market makers, implied volatility, hedging, price pressure, risk, dealers

Abstract:
We model the demand-pressure effect on prices when options cannot be perfectly hedged. The model shows that demand pressure in one option contract increases its price by an amount proportional to the variance of the unhedgeable part of the option. Similarly, the demand pressure increases the price of any other option by an amount proportional to the covariance of their unhedgeable parts. Empirically, we identify aggregate positions of dealers and end users using a unique dataset, and show that demand-pressure effects help explain well-known option-pricing puzzles. First, end users are net long index options, especially out-of-money puts, which helps explain their apparent expensiveness and the smirk. Second, demand patterns help explain the cross section of prices and skews of single-stock options.

Options, demand pressure, price pressure, frictions, liquidity

Abstract:
This paper examines option activity on value and growth stocks before earnings announcements. The main finding is that unsophisticated investors enter option positions that load up on growth stocks relative to value stocks in the days leading up to earnings announcements. This occurs despite the fact that at earnings announcements value stocks outperform growth stocks by a wide margin. The paper's results provide evidence that unsophisticated option market investors (1) overreact to past news on underlying stocks and (2) mistakenly believe that mispriced stocks will move even further away from fundamentals at impending scheduled news releases.

overreaction, value versus growth, option market, unsophisticated investors

Abstract:
There are a number of circumstances in finance where it is useful to estimate diffusion processes conditional on some event. In this paper, we develop the theoretical and numerical tools necessary to perform conditional estimation of diffusion processes within a generalized method of moments framework. We illustrate our method by estimating a univariate diffusion process for a standard time-series of interest rate data conditioned to remain between lower and upper boundaries. A test statistic fails to reject by a wide margin the linearity of the conditionally estimated drift coefficient.

Abstract:
We present strong evidence that option trading volume contains information about future stock price movements. Taking advantage of a unique dataset from the Chicago Board Options Exchange, we construct put-call ratios from option volume initiated by buyers to open new positions. On a risk-adjusted basis, stocks with low put-call ratios outperform stocks with high put-call ratios by more than 40 basis points on the next day and more than 1% over the next week. Partitioning our option signals into components that are publicly and non-publicly observable, we find that the economic source of this predictability is non-public information possessed by option traders rather than market inefficiency. We also find greater predictability from option signals for stocks with higher concentrations of informed traders and from option contracts with greater leverage.

Abstract:
This paper investigates the behavior of investors in the equity option market using a unique and detailed dataset of open interest and volume for all contracts listed on the Chicago Board Options Exchange over the 1990 through 2001 period. We document major stylized facts about the option market activity of three types of non-market maker investors over this time period and also investigate how their trading changed during the stock market bubble of the late 1990s and early 2000. Our key findings are: (1) non-market maker investors have about four times more long call than long put open interest, (2) these investors have more short than long open interest in both calls and puts, (3) each type of investor purchases more calls to open brand new positions when the return on underlying stocks are higher over horizons ranging from one week to two years into the past, (4) the least sophisticated group of investors substantially increased their purchases of calls on growth but not value stocks during the stock market bubble of the late 1990s and early 2000, and (5) none of the investor groups significantly increased their purchases of puts during the bubble period in order to overcome short sales constraints in the stock market.

Abstract:
We model demand-pressure effects on option prices. The model shows that demand pressure in one option contract increases its price by an amount proportional to the variance of the unhedgeable part of the option. Similarly, the demand pressure increases the price of any other option by an amount proportional to the covariance of the unhedgeable parts of the two options. Empirically, we identify aggregate positions of dealers and end-users using a unique dataset, and show that demand-pressure effects make a contribution to well-known option-pricing puzzles. Indeed, time-series tests show that demand helps explain the overall expensiveness and skew patterns of index options, and cross-sectional tests show that demand impacts the expensiveness of single-stock options as well.

Abstract:
We model demand-pressure effects on option prices. The model shows that demand pressure in one option contract increases its price by an amount pro- portional to the variance of the unhedgeable part of the option. Similarly, the demand pressure increases the price of any other option by an amount propor- tional to the covariance of their unhedgeable parts. Empirically, we identify aggregate positions of dealers and end users using a unique dataset, and show that demand-pressure effects contribute to well-known option-pricing puzzles. In- deed, time-series tests show that demand helps explain the overall expensiveness and skew patterns of both index options and single-stock options

Abstract:
We model the demand-pressure effect on prices when options cannot be perfectly hedged. The model shows that demand pressure in one option contract increases its price by an amount proportional to the variance of the unhedgeable part of the option. Similarly, the demand pressure increases the price of any other option by an amount proportional to the covariance of their unhedgeable parts. Empirically, we identify aggregate positions of dealers and end users using a unique dataset, and show that demand-pressure effects help explain well-known option-pricing puzzles. First, end users are net long index options, especially out-of-money puts, which helps explain their apparent expensiveness and the smirk. Second, demand patterns help explain the prices of single-stock options.

Abstract:
We present strong evidence that option trading volume contains information about future stock prices. Taking advantage of a unique data set, we construct put-call ratios from option volume initiated by buyers to open new positions. Stocks with low put-call ratios outperform stocks with high put-call ratios by more than 40 basis points on the next day and more than 1% over the next week. Partitioning our option signals into components that are publicly and nonpublicly observable, we find that the economic source of this predictability is nonpublic information possessed by option traders rather than market inefficiency. We also find greater predictability for stocks with higher concentrations of informed traders and from option contracts with greater leverage.

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 percent 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.

Volatility, Stock Options, Deriviatives, Information