heterogeneous information arrivals and return volatility dynamics uncovering the long run in high frequency returns recent empirical evidence suggests that the interdaily volatility clustering for most speculative returns are best characterized by a slowly mean reverting fractionally integrated process meanwhile much shorter lived volatility dynamics are typically observed with high frequency intradaily returns the present article demonstrates that by interpreting the volatility as a mixture of numerous heterogeneous short run information arrivals the observed volatility process may exhibit long run dependence as such the long memory characteristics constitute an intrinsic feature of the return generating process rather than the manifestation of occasional structural shifts these ideas are confirmed by our analysis of a one year time series of fiveminute deutschemark u s dollar exchange rates among the most puzzling issues is the behavior of volatility while the general properties of volatility remain elusive perhaps the most intriguing feature revealed by empirical work on volatility is its long persistence such behavior has sparked a search almost akin to that for the holy grail for the perfect garch model but the underlying question of why such volatility persistence endures remains unanswered we conjecture that the ability to analyze higher frequency data may be particularly useful in pursuing this issue goodhart and o hara 1997 the pronounced volatility clustering is arguably one of the most striking features of financial price series recorded at daily or weekly intervals and a large body of literature seeking to characterize this aspect of speculative returns has emerged over the past decade 1 at the same time convincing theoretical explanations for the underlying sources of long run persistence in volatility remain elusive the recent advent of comprehensive high frequency andersen is from the j l kellogg graduate school of management of northwestern university bollerslev is from the university of virginia and is a research associate at the national bureau of economic research we gratefully acknowledge the financial support provided by a research grant from the institute for quantitative research in finance the q group special thanks are due to olsen and associates for making the intradaily exchange rate quotes and reuter s news tape available we have received valuable comments from wake epps clive w j granger stephen f gray j huston mcculloch as well as seminar participants at the december 1996 triangle econometrics workshop the 1997 afa meetings in new orleans academia sinica the wharton school usc and georgetown and york universities we remain fully responsible for the content 1 see bollerslev chou and kroner 1992 for a survey of this literature using arch type

factorization of european and american option prices under complete and incomplete markets abstract in a standard option pricing model with continuous trading and diffusion processes this paper shows that the price of one european style option can be factorized into two intuitive components one robust x 0 which is priced by arbitrage and a second 0 which depends on a risk orthogonal to the traded securities this result implies the following 1 in an incomplete market these parts represent the price of a hedging portfolio which is unique and a premium which depends only on the risk premiums associated with the residual risk respectively 2 in a complete market it allows factoring the contribution of the different sources of risk to the final option price for example in a stochastic volatility model we can quantify the impact on the option price of volatility risk relative to market risk 0 and x 0 respectively hence certain misspricings in option markets can be directly related to the premium 0 3 moreover these results extend to american securities which have a third component an additional early exercise premium

losing money on the margin abstract margin trading is popular with retail investors around the world to limit the scale of these investors potential losses regulators impose a system of collateral requirements and margin calls we show in this paper however that the collateral requirement imposed by margin calls results in negative expected returns for these traders whilst also inducing positive skew in the returns distribution investments in assets with symmetric returns when traded on margin instead offer limited losses and a small chance of a large gain much like lottery stocks and other gambles we demonstrate this theoretically and then show empirically using a unique database of account data from a chinese retail brokerage that the realized losses of margin traders are often substantial this leads us to question whether current regulation is appropriate

cost benefit of water resource use in biofuel feedstock production abstract an increase in the output of crops such as cassava sugarcane and oil palm is necessary for biofuels development to increase the crop yield a large amount of water is required which can have an impact on the net social welfare this study aims to assess the benefit and cost of water resource use in biofuel crops production to support the cost benefit analysis of biofuels development benefit of water is presented through the value of its marginal product estimated by using economic valuation methods the loss due to water consumption is assessed and monetized based on life cycle impact assessment to show how the approach is applied to the regional level thailand is considered as a case study the results show that the economic gains from using a cubic meter of water in cassava sugarcane and oil palm production are 1 6 6 9 1 0 5 0 and 0 8 2 9 thai baht respectively however using this amount of water can also bring about the external cost around 0 2 thai baht leading to the net benefits of using a cubic meter of water in cassava sugarcane and oil palm production between 1 5 and 6 7 0 9 4 8 and 0 6 2 6 thai baht respectively gain and loss of the water used in cassava sugarcane and oil palm cultivation are expressed in monetary units for the first time by this study besides this paper could be a guideline for future research towards an integration of life cycle impact assessment and the economic analysis tool cost benefit analysis

stock returns and volatility a firm level analysis abstract it has been previously documented that individual firms stock return volatility rises after stock prices fall this paper finds that this statistical relation is largely due to a positive contemporaneous relation between firm stock returns and firm stock return volatility this positive relation is strongest for both small firms and firms with little financial leverage at the aggregate level the sign of this contemporaneous relation is reversed the reasons for the difference between the aggregate and firm level relations are explored

the american put option valued analytically an analytic solution to the american put problem is derived herein the hedge ratio and other derivatives of the solution are presented the formula derived implies an exact duplicating portfolio for the american put consisting of discount bonds and stock sold short the formula is extended to consider put options on stocks paying cash dividends a polynomial expression is developed for evaluating these formulae values and hedge ratios for puts on both dividend and nondividend paying stocks are calculated tabulated and compared with values derived by numerical integration and binomial approximation as with european options evaluating an analytic formula is more efficient than approximating the stock price process or the partial differential equation by binomial or finite difference methods finally applications of this american put solution are discussed

margin regulation and stock market volatility using daily and monthly stock returns we find no convincing evidence that federal reserve margin requirements have served to dampen stock market volatility the contrary conclusion expressed in recent papers by hardouvelis 1988a b is traced to flaws in his test design we do detect the expected negative relation between margin requirements and the amount of margin credit outstanding we also confirm the recent finding by schwert 1988 that changes in margin requirements by the fed have tended to follow rather than lead changes in market volatility after 55 years stock market margin requirements are again a source of controversy the securities and exchange act of 1934 transferred to the federal reserve system the authority exercised previously by the new york stock exchange and other private sector exchanges to set the minimum margins i e down payments that securities brokers and dealers subsequently expanded to all lenders must require of customers purchasing common stocks on credit the transfer of authority reflected the view widely held at the time that the low initial margins set by the exchanges had fueled the stock market boom of the 1920 s and that the frenzied liquidation of shares in response to margin calls had accelerated the crash in october 1929 supposedly dragging the economy down with it congress hoped that timely raising of margin requirements by the monetary authorities might dampen speculative excesses before they raged out of control or in today s terms that margin controls might reduce market volatility what the federal reserve has done since then with its margin setting authority can be seen from figure 1 which shows the time paths both of margins and one measure of market volatility from october 1934 to december 1987 margin requirements were set initially at 45 percent raised to 55 percent during the boomlet of 1936 and then cut back to a low of 40 percent after the sharp stockmarket break in the autumn of 1937 the requirement stayed at that level for the remainder of the 30 s and most of the war years but was stepped up sharply as the war drew to a close reaching 100 percent i e all cash no borrowing for most of 1946 changes were frequent over the next two and a half decades

the analytic valuation of american options no analytic solutions exists for the valuation of american options written on futures contracts and foreign currencies for which early exercise may be optimal this article formulates the american option valuation problem in economically and mathematically meaningful ways this enables us to derive valuation formulas for american options the properties associated with the optimal exercise boundary are examined and a numerical technique to implement the valuation formulas is presented article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

asset pricing with heterogeneous preferences beliefs and portfolio constraints portfolio constraints are widespread and have significant effects on asset prices this paper studies the effects of constraints in a dynamic economy populated by investors with different risk aversions and beliefs about the rate of economic growth the paper provides a comparison of various constraints and conditions under which these constraints help match certain empirical facts about asset prices under these conditions borrowing and short sale constraints decrease stock return volatilities whereas limited stock market participation constraints amplify them moreover borrowing constraints generate spikes in interest rates and volatilities and have stronger effects on asset prices than short sale constraints

margin requirements speculative trading and stock price fluctuations the case of japan an increase in margin requirements in the first section of the tokyo stock exchange is followed by a decline in margin borrowing trading volume the proportion of trading performed through margin accounts the growth in stock prices and the conditional volatility of daily returns the nonmarginable second section stocks show a smaller change in volatility and only a delayed weak price response the hypothesis that margin requirements restrict the behavior of destabilizing speculators can explain these correlations but cannot explain the observation that individuals the most active users of margin funds appear to be good market timers

monte carlo valuation of american options through computation of the optimal exercise frontier this paper introduces a monte carlo simulation method for pricing multidimensional american options based on the computation of the optimal exercise frontier we consider bermudan options that can be exercised at a finite number of times and compute the optimal exercise frontier recursively we show that for every date of possible exercise any single point of the optimal exercise frontier is a fixed point of a simple algorithm once the frontier is computed we use plain vanilla monte carlo simulation to price the option and obtain a low biased estimator we illustrate the method with applications to several types of options

evaluation of american option prices in a path integral framework using fourier hermite series expansions abstract in this paper we review the path integral technique which has wide applications in statistical physics and relate it to the backward recursion technique which is widely used for the evaluation of derivative securities we formulate the pricing of equity options both european and american using the path integral framework discretising in the time variable and using expansions in fourier hermite series for the continuous representation of the underlying asset price we show how these options can be evaluated in the path integral framework for american options the solution technique facilitates the accurate determination of the early exercise boundary as part of the solution additionally the continuous representation of the state variable allows the relatively accurate and efficient evaluation of the option prices and the delta hedge ratio

prudent margin levels in the finnish stock index futures market futures market officials are confronted with the difficult task of setting appropriate margin levels that must balance the costs of trader default and the benefits of increased market liquidity one way to guard against default is prudent margin setting practices designed to protect futures positions from extreme price movements the objective of this research is to extrapolate the probabilities of encountering extreme price movements by applying statistical extreme value theory to the finnish stock index futures market the extreme value technique is found to be appropriate since it generates theoretical margin violation probabilities that closely follow the empirical probability distribution the extrapolated results provide decision makers information on extreme events that have not yet occurred

pde methods for pricing barrier options abstract this paper presents an implicit method for solving pde models of contingent claims prices with general algebraic constraints on the solution examples of constraints include barriers and early exercise features in this unified framework barrier options with or without american style features can be handled in the same way either continuously or discretely monitored barriers can be accommodated as can time varying barriers the underlying asset may pay out either a constant dividend yield or a discrete dollar dividend the use of the implicit method leads to convergence in fewer time steps compared to explicit schemes this paper also discusses extending the basic methodology to the valuation of two asset barrier options and the incorporation of automatic time stepping

stock prices and volume the authors undertake a comprehensive investigation of price and volume co movement using daily new york stock exchange data from 1928 to 1987 they adjust the data to take into account well known calendar effects and long run trends to describe the process they use a seminonparametric estimate of the joint density of current price change and volume conditional on past price changes and volume four empirical regularities are found 1 positive correlation between conditional volatility and volume 2 large price movements are followed by high volume 3 conditioning on lagged volume substantially attenuates the leverage effect and 4 after conditioning on lagged volume there is a positive risk return relation article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

the effect of short selling and borrowing on market prices and traders behavior this paper studies the influence of allowing borrowing and short selling on market prices and traders forecasts in an experimental asset market we verify although not statistically significantly so that borrowing tends to increase asset overvaluation and price orecasts while short selling tends to reduce these measures we also show that a number of results on beliefs traders types cognitive sophistication and earnings obtained in earlier experimental studies in which borrowing and short selling are not possible generalize to markets with borrowing and short sales

dynamic equilibrium with two stocks heterogeneous investors and portfolio constraints we study dynamic equilibrium in a lucas economy with two stocks two heterogeneous constant relative risk aversion investors and portfolio constraints we focus on margin and leverage constraints which restrict access to credit we find a positive relationship between the amount of leverage in the economy and magnitudes of stock return correlations and volatilities tighter constraints generate rich patterns in correlations and volatilities make them less countercyclical increase risk premia proportionally to assets margins and increase prices of low margin assets more than prices of high margin assets we derive closed form solutions for the unconstrained case and the case of leverage constraints

tight bounds on american option prices in contrast to the constant exercise boundary assumed by broadie and detemple 1996 broadie m detemple j 1996 american option valuation new bounds approximations and comparison of existing methods review of financial studies 9 1211 1250 we use an exponential function to approximate the early exercise boundary then we obtain lower bounds for american option prices and the optimal exercise boundary which improve the bounds of broadie and detemple 1996 with the tight lower bound for the optimal exercise boundary we further derive a tight upper bound for the american option price using the early exercise premium integral of kim 1990 kim i j 1990 the analytic valuation of american options review of financial studies 3 547 572 the numerical results show that our lower and upper bounds are very tight and can improve the pricing errors of the lower bound and upper bound of broadie and detemple 1996 by 83 0 and 87 5 respectively the tightness of our upper bounds is comparable to some best accurate efficient methods in the literature for pricing american options moreover the results also indicate that the hedge ratios deltas and gammas of our bounds are close to the accurate values of american options

pricing american options on foreign assets in a stochastic interest rate economy this paper values american options on foreign assets in a stochastic interest rate economy using a two point geske and johnson 1984 technique the method requires the valuation of just two options a european option and a twice exercisable option i first derive the risk neutral distributions of asset prices under two forward risk adjusted measures closedform solutions for european options on foreign assets are then obtained by applying these risk neutral distributions this article also provides analytic solutions for pricing twiceexercisable options that are at most two dimensional even though the valuation problem involves four risk factors at two exercise dates i report the results of numerical evaluations of american option values using my method and show how they vary with the interest rate parameters i also verify the accuracy of the proposed method by comparing with the benchmark values obtained from the least square method of longstaff and schwartz 2001

the irrelevance of margin evidence from the crash of 87 following the crash of 1987 one contentious regulatory issue has been whether margin activity exacerbated the decline in equity values we contrast the crash behavior of nasdaq securities eligible for margin trading with the behavior of ineligible ones consistent with the hypothesis that margin eligible securities were more frequently subjected to margin calls and forced sales we find that abnormal volumes were uniformly larger for eligible securities however there is no evidence that this activity provoked additional price depreciation margin eligible securities actually fell by one percent less than the ineligible securities over the period

margin requirements volatility and the transitory component of stock prices official margin requirements in the u s stock market were established in october 1934 to limit the amount of credit available for the purpose of buying stocks since then higher or rising margin requirements are associated with lower stock price volatility lower excess volatility and smaller deviations of stock prices from their fundamental values the results hold throughout the post 1934 period and are not very sensitive to the exclusion of the turbulent depression years from the sample thus margin requirements seem to be an effective policy tool in curbing destabilizing speculation jel 313 520 federal regulation of securities margins was mandated by congress in the securities exchange act of 1934 the stock market experience of the late 1920s led congress to the conclusion that credit financed speculation in the stock market might create excessive market volatility through a pyramidingdepyramiding process congress reasoned that the imposition of margin requirements could constrain the amount of borrowing and prevent excessive market volatility and subsequently gave the federal reserve jurisdiction over the level of margin requirements since 1934 the federal reserve

the valuation of american barrier options using the decomposition technique in this paper we propose an alternative approach for pricing and hedging american barrier options speci cally we obtain an analytic representation for the value and hedge parameters of barrier options using the decomposition technique of separating the european option value from the early exercise premium this allows us to identify some new put call symmetry relations and the homogeneity in price parameters of the optimal exercise boundary these properties can be utilized to increase the computational e ciency of our method in pricing and hedging american options our implementation of the obtained solution indicates that the proposed approach is both e cient and accurate in computing option values and option hedge parameters our numerical results also demonstrate that the approach dominates the existing lattice methods in both accuracy and e ciency in particular the method is free of the di culty that existing

an fft network for levy option pricing abstract this paper develops a simple network approach to american exotic option valuation under levy processes using the fast fourier transform fft the forward shooting grid fsg technique of the lattice approach is then generalized to expand the fft network to accommodate path dependent variables this network pricing approach is applicable to all levy processes for which the characteristic function is readily available in other words the log value of the underlying asset can follow finite activity or infinite activity levy processes with the powerful computation of fft the proposed network has a negligible additional computational burden compared to the binomial tree approach the early exercise policy and option values in the continuation region are determined in a way very similar to that of the lattice approach numerical examples using american style barrier lookback and asian options demonstrate that the fft network is accurate and efficient

extreme coexceedances in new eu member states stock markets abstract we analyze the financial integration of the new european union eu member states stock markets using the negative positive coexceedance variable that counts the number of large negative large positive returns on a given day across the countries a similar analysis is performed for the old eu countries we use a multinomial logit model to investigate how persistence asset classes and volatility are related to the coexceedance variables we find that the effects differ a between negative and positive coexceedance variables b between old and new eu member states and c before and after the eu enlargement in 2004 suggesting a closer connection of new eu stock markets to those in western europe

robust pricing of the american put option a note on richardson extrapolation and the early exercise premium this paper presents a detailed analysis of the numerical implementation of the american put option decomposition into an equivalent european option plus an early exercise premium kim 1990 jacka 1991 carr et al 1992 it subsequently introduces a new algorithm based upon this decomposition and richardson extrapolation this new algorithm is based upon a the derivation of the correct order for the error term when applying richardson extrapolation which is used to control the error of the extrapolated prices b an innovative adjustment of kim s 1990 discrete time early exercise premium so that these premiums monotonically converge and therefore it is appropriate to use them in extrapolation and c the optimal exercise frontier can be quickly computed through newton s method permitting the efficient implementation of the decomposition formula in practice numerical experiments show that this new algorithm is accurate efficient easy to implement and competitive in comparison with other methods finally it can also be applied to other american exotic securities

margin requirements price fluctuations and market participation in metal futures margin requirements in metal futures contracts have a negative impact on market participation that seems causal because it is absent from a benchmark group of metals that do not undergo similar margin changes it is less clear whether margins restrict primarily rational or irrational investors the stronger positive relation between margins and future target metal volatility than benchmark metal volatility can simply be attributed to the selection rule of the exchanges as they increase margins in those metals for which they anticipate a comparatively higher future volatility copyright 1995 by ohio state university press

the asymmetric relation between initial margin requirements and stock market volatility across bull and bear markets higher initial margin requirements are associated with lower subsequent stock market volatility during normal and bull periods but show no relationship during bear periods higher margins are also negatively related to the conditional mean of stock returns apparently because they reduce systemic risk we conclude that a prudential rule for setting margins or other regulatory restrictions is to lower them in sharply declining markets in order to enhance liquidity and avoid a depyramiding effect in stock prices but subsequently raise them and keep them at the higher level in order to prevent a future pyramiding effect copyright 2002 oxford university press

margin regulation and volatility an infinite horizon asset pricing model with heterogeneous agents and collateral constraints can explain why adjustments in stock market margins under us regulation t had an economically insignificant impact on market volatility in the model raising the margin requirement for one asset class may barely affect its volatility if investors have access to another unregulated class of collateralizable assets through spillovers however the volatility of the other asset class may substantially decrease a very strong dampening effect on all assets return volatilities can be achieved by a countercyclical regulation of all markets

stock returns and volatility most asset pricing models postulate a positive relationship between a stock portfolio s expected returns and risk which is often modeled by the variance of the asset price this paper uses garch in mean models to examine the relationship between mean returns on a stock portfolio and its conditional variance or standard deviation after estimating a variety of models from daily and monthly portfolio return data we conclude that any relationship between mean returns and own variance or standard deviation is weak the results suggest that investors consider some other risk measure to be more important than the variance of portfolio returns