the forecasting ability of correlations implied in foreign exchange options abstract this paper evaluates the forecasting accuracy of correlations derived from implied volatilities in dollar mark dollar yen and mark yen options from january 1989 to may 1995 as a forecast of realized correlation between the dollar mark and dollar yen implied correlation is compared against three alternative forecasts based on time series data historical correlation riskmetrics exponentially weighted moving average correlation and correlation estimated using a bivariate garch 1 1 model at the 1 month and 3 month forecast horizons we find that implied correlation outperforms often significantly these alternative forecasts in combinations implied correlation always incrementally improves the performance of other forecasts but not the converse in certain cases historically based forecasts contribute no incremental information to implied forecasts the superiority of the implied correlation forecast holds even when forecast errors are weighted by realized variances reflecting correlation s contribution to the dollar variance of a multicurrency portfolio

impact of the carbon price on the integrating european electricity market we study the impact of the carbon price on the integrating electricity market in the eu our theoretical framework suggests that the price of carbon has a positive but uneven impact on electricity prices depending on the marginal production plant the carbon price may increase price differences in the short run we apply time series analysis on daily forward data from 2003 to 2011 and investigate whether we can find empirical evidence for our analytical findings our results support the hypotheses that integration in electricity prices has increased over time and that the carbon price has a positive but uneven impact on the integration of prices

answering the skeptics yes standard volatility models do provide accurate forecasts a voluminous literature has emerged for modeling the temporal dependencies in financial market volatility using arch and stochastic volatility models while most of these studies have documented highly significant in sample parameter estimates and pronounced intertemporal volatility persistence traditional ex post forecast evaluation criteria suggest that the models provide seemingly poor volatility forecasts contrary to this contention we show that volatility models produce strikingly accurate interdaily forecasts for the latent volatility factor that would be of interest in most financial applications new methods for improved ex post interdaily volatility measurements based on high frequency intradaily data are also discussed

the pricing of options on assets with stochastic volatilities one option pricing problem that has hitherto been unsolved is the pricing of a european call on an asset that has a stochastic volatility this paper examines this problem the option price is determined in series form for the case in which the stochastic volatility is independent of the stock price numerical solutions are also produced for the case in which the volatility is correlated with the stock price it is found that the black scholes price frequently overprices options and that the degree of overpricing increases with the time to maturity one option pricing problem that has hitherto remained unsolved is the pricing of a european call on a stock that has a stochastic volatility from the work of merton 12 garman 6 and cox ingersoll and ross 3 the differential equation that the option must satisfy is known the solution of this differential equation is independent of risk preferences if a the volatility is a traded asset or b the volatility is uncorrelated with aggregate consumption if either of these conditions holds the risk neutral valuation arguments of cox and ross 4 can be used in a straightfoward way this paper produces a solution in series form for the situation in which the stock price is instantaneously uncorrelated with the volatility we do not assume that the volatility is a traded asset also a constant correlation between the instantaneous rate of change of the volatility and the rate of change of aggregate consumption can be accommodated the option price is lower than the blackscholes b s 1 price when the option is close to being at the money and higher when it is deep in or deep out of the money the exercise prices for which overpricing by b s takes place are within about ten percent of the security price this is the range of exercise prices over which most option trading takes place so we may in general expect the b s price to overprice options this effect is exaggerated as the time to maturity increases one of the most surprising implications of this is that if the b s equation is used to determine the implied volatility of a near the money option the longer the time to maturity the lower the implied volatility numerical solutions for the case in which the volatility is correlated with the stock price are also examined the stochastic volatility problem has been examined by merton 13 geske 7 johnson 10 johnson and shanno 11 eisenberg 5 wiggins 16 and

the information content of implied stochastic volatility from currency options this paper investigates the predictability of implied variances extracted frorn currency options under the assumption that the options market is informationally efficient and that options are priced according to the models of black scholes 1973 hull white 1987 and heston 1993 implied variances are estimated from transaction prices of currency options traded on the philadelphia stock exchange phlx if implied variances are efficient variance forecasts from time series models should have no predictive power for subsequently realized market variances the empirical evidence on testing the implied volatility hypothesis is mixed latane and rendleman 1976 and chiras and manaster 1978 find evidence favourable to the hypothesis the weighted implied standard deviation explains more of the cross sectional variation in the future standard deviations of individual security returns than do historical volatilities day and lewis 1992 find that the implied volatilities from the s p 100 index options contain incremental information for the garch models canina and figlewski 1993 find evidence against the hypothesis the implied volatilities from s p 100 index options have less predictive power for subsequently realized volatility than simple historical volatilities lamoureux and lastrapes 1993 make the first attempt to introduce the stochastic volatility option model into the study of implied volatility their tests on individual stock options reject the orthogonality restriction that the forecast from time series models should not have predictive power in addition to implied volatility these findings based on stock index and individual stock options are inconsistent with the hypothesis that implied volatility is the optimal predictor of future volatility this contradiction motivates the present paper which explores the performance of implied volatility in the foreign exchange market the paper seeks to extend existing research by a reducing measurement errors b adopting stochastic volatility option pricing models and c improving the techniques of statistical inference

the informational content of implied volatility implied volatility is widely believed to be informationally superior to historical volatility because it is the markets forecast of future volatility but for s p 100 index options the most actively traded contract in the united states we find implied volatility in aggregate and across subsamples separated by maturity and strike price implied volatility has virtually no correlation with future volatility and it does not incorporate the information contained in recent observed volatility article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

trading mechanisms and stock returns an empirical investigation this paper examines the effects of the mechanism by which securities are traded on their price behavior we compare the behavior of open to open and close to close returns on nyse stocks given the differences in execution methods applied in the opening and closing transactions opening returns are found to exhibit greater dispersion greater deviations from normality and a more negative and significant autocorrelation pattern than closing returns we study the effects of the bid ask spread and the price adjustment process on the estimated return variances and covariances and discuss the associated biases we conclude that the trading mechanism has a significant effect on stock price behavior

the risk premium that never was a fair value explanation of the volatility spread abstract we present a new framework to investigate the profitability of trading the volatility spread the upward bias on implied volatility as an estimator of future realized volatility the scheme incorporates the first four option implied moments in a growth optimal payoff that is statically replicated using a portfolio of options removing the upward bias on implied volatility worsens the likelihood score of risk neutral densities obtained from s p 500 index options when they are used as forecasts of the underlying index return distribution it also results in negative expected capital growth when they are used in a volatility arbitrage scheme our empirical finding is that the upward bias on implied volatility does not represent a long term return premium rather it is required to mitigate the large losses associated with tail events when trading volatility in options markets

the predictive power of implied volatility evidence from 35 futures markets abstract using data from 35 futures options markets from eight separate exchanges we test how well the implied volatilities ivs embedded in option prices predict subsequently realized volatility rv in the underlying futures we find that for this broad array of futures options iv performs well in a relative sense for a large majority of the commodities studied the implieds outperform historical volatility hv as a predictor of the subsequently rv in the underlying futures prices over the remaining life of the option indeed in most markets examined regardless of whether it is modeled as a simple moving average or in a garch framework hv contains no economically significant predictive information beyond what is already incorporated in iv these findings add to previous research that has focused on currency and crude oil futures by extending the analysis into a very broad array of contracts and exchanges our results are consistent with the hypothesis that futures options markets in general with their minimal trading frictions are efficient

stochastic volatility option pricing this paper examines alternative methods for pricing options when the underlying security volatility is stochastic we show that when there is no correlation between innovations in security price and volatility the characteristic function of the average variance of the price process plays a pivotal role it may be used to simplify fourier option pricing techniques and to implement simple power series methods we compare these methods for the alternative mean reverting stochastic volatility models introduced by stein and stein 1991 and heston 1993 we also examine the biases in the black scholes model that are eliminated by allowing for stochastic volatility and we correct some errors in the stein and stein 1991 analysis of this issue empirical evidence on underlying asset prices and on their derivatives strongly suggests that asset price volatility is stochastic the pricing of options under this condition is therefore an important problem in this paper we study alternative option pricing methods that account for stochastic volatility we are particularly concerned with power series methods which we show to be quite accurate and easy to implement for alternative volatility specifications we point out their relation with recently proposed exact methods this permits a precise assessment of the approximation involved in the simple power series approach and of the impact of stochastic volatility on option prices following garman 1976 stochastic volatility option prices must satisfy a bivariate fundamental partial differential equation pde in the two state variables security price and volatility since volatility is not spanned by assets in the econ omy the volatility risk may not be eliminated by arbitrage methods therefore its market price explicitly enters into the pde the associated risk premium is owen graduate school of management vanderbilt university nashville tn 37203 and universita di siena facolta di scienza economiche e bancarie 53100 siena italy respectively part of this research was supported from a grant from the dean s fund and the financial markets research center at the owen school of management vanderbilt university some of this research was completed while roma was visiting the anderson graduate school of management ofthe university of california at los angeles we thank participants of the finance accounting and economics workshop at the owen school of management vanderbilt university for useful comments we appreciate the suggestions of roger huang craig lewis ron masulis and walter torous we thank joanne ball for editorial

the ex ante and ex post price effects of quarterly earnings announcements reflected in option and stock prices the subject of this study is the effect of investors anticipations of impending informative disclosures on the behavior of option and stock prices our approach introduced in a previous paper patell and wolfson 1979 and substantially extended here represents the following significant departure from traditional information content studies instead of analyzing security price reactions to announcements we analyze preannouncement option prices in order to discern investors beliefs about the range of possible stock price reactions expected to accompany a forthcoming disclosure whose actual content is not yet known in the tests reported here we focus on quarterly earnings announcements as disclosure events whose timing is predictable and we attempt to detect their systematic influence on the relationship between stock and option prices our operational definition of information content emphasizes changes in the variability of common stock returns in response to earnings disclosures while market efficiency precludes investors from predicting the direction of the stock price change which will accompany a future earnings announcement it is likely that investors will anticipate increased price variability at the time of disclosure and indeed several studies have documented announcement date increases in stock price volatility

overreactions in the options market this paper examines the term structure of options implied volatilities using data on s p 100 index options because implied volatility is strongly mean reverting the implied volatility on a longer maturity option should move by less than one percent in response to a one percent move in the implied volatility of a shorter maturity option empirically this elasticity turns out to be larger than suggested by rational expectations theory long maturity options tend to overreact to changes in the implied volatility of short maturity options are investors rational do they behave like bayesian statisticians when it comes to incorporating new information into asset prices proponents of the efficient markets hypothesis would answer this question in the affirmative many others however believe that bayesian rationality is a poor description of investor behavior and that as a consequence asset prices tend to be informationally inefficient one way in which inefficiencies might arise is through the overreactions of traders to the arrival of new information 1 this possibility is raised by experimental and survey findings which indicate that people have a systematic tendency to overemphasize recent data at the expense of other information when making projections 2 the objective of this paper is to search for evidence of such overreactive behavior in a semingly peculiar place the options market options may appear to be unlikely candidates for overreaction because unlike primary securities their prices are closely tied down by arbitrage considerations as black and scholes 1973 demonstrate if stock price volatility is known options prices are completely determined any deviation from the prescribed value implies a riskless profit opportunity however given that volatility is in fact unknown and changing options do retain something of an independent nature not wholly redundant with their underlying stocks options can be thought of as reflecting a speculative market in volatility the implied volatility on a given option obtained by inverting a

forecasting stock return variance toward an understanding of stochastic implied volatilities we examine the behavior of measured variances from the options market and the underlying stock market under the joint hypotheses that markets are informationally efficient and that option prices are explained by a particular asset pricing model forecasts from time series models of the stockreturn process should not have predictive content given the market forecast as embodied in option prices both in sample and out of sample tests suggest that this hypothesis can be rejected using simulations we show that biases inherent in the procedure we use to imply variances cannot explain this result thus we provide evidence inconsistent with the orthogonality restrictions of option pricing models that assume that variance risk is unpriced these results also have implicationsfor optimal variance forecast rules

volatility in crude oil futures a comparison of the predictive ability of garch and implied volatility models the wti future contract quoted at the nymex is the most actively traded instrument in the energy sector this paper compares the predictive ability of two approaches which can be used to forecast volatility garch type models where forecasts are obtained after estimating time series models and an implied volatility model where forecasts are obtained by inverting one of the models used to price options although the main scope of the research discussed here is to evaluate which model produces the best forecast of volatility for the wti future contract evaluated according to statistical and regression based criteria we also investigate whether volatility of the oil futures are affected by asymmetric effects whether parameters of the garch models are influenced by the distribution of the errors and whether allowing for a time varying long run mean in the volatility produces any improvement on the forecast obtained from garch models

predictable dynamics in implied volatility surfaces from otc currency options recent empirical studies report predictable dynamics in the volatility surfaces that are implied by observed index option prices such as those prescribed by general equilibrium models using an extensive data set from the over the counter options market we document similar predictability in the factors that capture the daily variation of surfaces implied by options on 25 different foreign exchange rates we proceed to demonstrate that simple vector autoregressive specifications for the factors can help produce accurate out of sample forecasts of the systematic component of the surface at short horizons profitable delta hedged positions can be set up based on these forecasts however profits disappear when typical transaction costs are taken into account and when trading rules on wide segments of the surface are sought

forecasting daily exchange rate volatility using intraday returns abstract this study investigates whether intraday returns contain important information for forecasting daily volatility whereas in the existing literature volatility models for daily returns are improved by including intraday information such as the daily high and low volume the number of trades and intraday returns here the volatility of intraday returns is explicitly modelled daily volatility forecasts are constructed from multiple volatility forecasts for intraday intervals it is shown for the dem usd and the yen usd exchange rates that this results in superior forecasts for daily volatility

implications of the discreteness of observed stock prices stock prices on the organized exchanges are restricted to be divisible by 1 8 therefore the true price usually differs from the observed price this paper examines the biases resulting from the discreteness of observed stock prices it is shown that the natural estimators of the variance and all of the higher order moments of the rate of returns are biased an approximate set of correction factors is derived and a procedure is outlined to show how the correction can be made the natural estimators of the beta and of the variance of the market portfolio on the other hand are nearly unbiased the behavior of stock prices has been an issue of interest to the financial economist for many years this interest resulted in a growing number of empirical studies which attempt to estimate this behavior e g blattberg and gonedes 2 fama 6 fama and roll 7 8 barnea and downes 1 to date stock price behavior is estimated under the assumption that the observed trading price is the true equilibrium price however observed stock prices and stock price changes on the organized exchanges are restricted to multiples of 1 8 of a dollar 1 therefore if the true distribution of stock prices is continuous an observed trading price can be different from the true price this paper examines the biases in estimating the moments of stock price changes caused by the discreteness of observed stock prices the major focus of the paper is in noting this problem providing a model which explains the source of these biases and quantifying their size section i demonstrates that due to the discrete nature of observed stock prices the natural estimators for the variance and for the higher order moments of the rate of returns are biased upward this bias is larger for stocks with lower prices and smaller standard deviation for instance assuming that the standard deviation a is 0 001 the stock price is one dollar the true probability distribution of stock prices is lognormal and the observed prices are as close as possible to the true prices then the natural estimator of r has expectation 0 01400 hence it is biased upward by 1300 significant biases have important implications in option pricing we derive an approximate set of correction factors which can be applied to the

a note on the behavior of stock returns around ex dates of stock distributions stock returns after the ex split date is significantly higher than the presplit volatility the increase in the standard deviation of daily returns is of the order of twenty eight to thirty five percent and persists for as long as a full year after the ex date even more interesting is their finding that there is no permanent change in the variance of returns at the announcement date they investigate several potential explanations for this aberration but are unable to find a satisfactory answer grinblatt masulis and titman 6 henceforth gmt examine the behavior of expected returns around announcement dates and exdates for stock distributions exceeding ten percent classifying stock distributions as either stock dividends split factors of twenty five percent or less or stock splits they conclude that return behavior differs across these two types of distributions with stock dividends exhibiting larger abnormal returns than splits this is interpreted by them as evidence in favor of the retained earnings hypothesis the dissimilar accounting treatment of these two types of stock distributions affects retained earnings in different ways and hence splits are not simply large stock dividends this paper extends the work of op to all types of stock distributions in section i postsplit variance is shown to be different from the presplit variance for small stock splits and stock dividends while small splits display an increase in volatility like large splits stock dividends are associated with a decrease in the volatility of returns this evidence also supports gmt s conclusions that stock splits and stock dividends are different types of events section ii investigates the volatility of returns for reverse splits and demonstrates that postsplit volatility decreases for these events this evidence is complementary to woolridge and chambers 9 findings that reverse splits are also associated with negative abnormal returns at their announcement and ex dates section iii concludes the paper

the persistence of volatility and stock market fluctuations this paper examines the potential influence of changing volatility in stock market prices on the level of stock market prices it demonstrates that volatility is only weakly serially correlated implying that shocks to volatility do not persist these shocks can therefore have only a small impact on stockmarket prices since changes in volatility affect expected required rates of return for relatively short intervals these findings lead us to be skeptical of recent claims that the stock market s poor performance during the 1970 s can be explained by volatility induced increases in risk premia this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item this abstract was borrowed from another version of this item

option values under stochastic volatility theory and empirical estimates abstract this paper numerically solves the call option valuation problem given a fairly general continuous stochastic process for return volatility statistical estimators for volatility process parameters are derived and parameter estimates are calculated for several individual stocks and indices the resulting estimated option values do not differ dramatically from black scholes values in most cases although there is some evidence that for longer maturity index options black scholes overvalues out of the money calls in relation to in the money calls

the creation and resolution of market uncertainty the impact of information releases on implied volatility we model and examine the impact of information releases on market uncertainty as mea sured by the implied standard deviation isd from option markets distinguishing between scheduled and unscheduled announcements we hypothesize that since the timing although not the content of scheduled announcements is known a priori the pre release isd will impound the anticipated impact of important releases on price volatility and that the isd will normally decline post release as this uncertainty is resolved conversely we hypothesize that the unexpected high volatility caused by major unscheduled releases will cause market participants to adjust upward their estimates of likely volatility over the remaining life of the option resulting in an increase in the isd our evidence supports both hypotheses the isds that we consider are from the t bond eurodollar and deutschemark options markets we examine scheduled macroeconomic news releases such as the employment report and the ppi we also find that the observed tendency for the isd to fall on fridays and rise on mondays is due to the weekday pattern of scheduled news releases

index options the early evidence index options became the most important traded contracts during their first year of existence two contracts namely those on the s p100 and the major markets index have a trading volume which typically surpasses the trading volume in all individual stock option contracts in this paper we examine the pricing of the options on the s p100 and the major markets index using intra day prices we find the options frequently violate the arbitrage boundary put call parity and are substantially mispriced relative to theoretical values our results suggest that tests of option pricing models may be more difficult than previously realized due to nonsynchronous prices even using real time data from the exchanges

information control in the principal agent problem this paper compares the principal s payoff in agency models under different assumptions about the agent s access to information the agent may make decisions before is uninformed or after is informed learning the state of nature when there are two possible outcomes the principal typically prefers informed to uninformed agents whether the agent receives the information before or after contracting this result is false when there are more than two outcomes conditions under which a principal prefers one agent to another when the agents differ only in their disutility of effort are also given copyright 1993 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

what do economists know an empirical study of experts expectations for more than three decades economic columnist joseph a livingston has canvassed a panel of economists twice a year eliciting their six month and twelve month forecasts for more than a dozen key variables this study analyzes whether the experts predictions are unbiased and whether complete use was made of all relevant known information unbiasedness and completeness being necessary conditions for fully rational expectations little bias was found in either the half year or full year predictions but extensive underutilization of information particularly data on monetary growth occurred to prophecy is extremely difficult especially with respect to the future chinese proverb do economists expectations regarding key price and nonprice variables utilize all known relevant information in an unbiased efficient manner this is a worthy subject for research for several reasons properties of experts predictions likely form an upper bound for those of laymen further as john muth 14 has noted the character of dynamic processes is typically very sensitive to the way expectations are influenced by the actual course of events p 316 hence we need to know precisely how events do affect expectations finally the common practice of replacing a variable s generally unobserved expectation with a proxy based on its past values will be unbiased and will not cause bias in other

standard deviations implied in option prices as predictors of future stock price variability abstract standard deviations implied in option prices have recently been introduced as being better than average predictors of future stock price variability this article specifically studies the predictive ability of implicit standard deviations taking into account the dividend problem and the problem of optimal weighting schemes of the standard deviations when there are several options on the same stock transaction data information was used to study the importance of non simultaneities in observing stock and option prices

nonparametric tests of alternative option pricing models using all reported trades and quotes on the 30 most active cboe option classes from august 23 1976 through august 31 1978