information acquisition and under diversification if an investor wants to form a portfolio of risky assets and can exert effort to collect information on the future value of these assets before he invests which assets should he learn about the best assets to acquire information about are ones the investor expects to hold but the assets the investor holds depend on the information he observes we build a framework to solve jointly for investment and information choices with general preferences and information cost functions although the optimal research strategies depend on preferences and costs the main result is that the investor who can first collect information systematically deviates from holding a diversified portfolio information acquisition can rationalize investing in a diversified fund and a concentrated set of assets an allocation often observed but usually deemed anomalous copyright wiley blackwell

when transparency improves must prices reflect fundamentals better no in the presence of speculative opportunities investors can learn about both asset fundamentals and the beliefs of other traders we show that this learning exhibits complementarity learning more along one dimension increases the value of learning about the other as a result regulatory changes may be counterproductive first increasing transparency i e making fundamental information cheaper to acquire can make prices less informative when investors respond by learning relatively more about others second public disclosures discourage private learning about fundamentals while encouraging information acquisition about others accordingly disclosing more fundamental information can decrease overall informational efficiency by decreasing price informativeness received april 20 2016 editorial decision september 30 2017 by editor itay goldstein

does ambiguity aversion survive in experimental asset markets although a number of theoretical studies explain empirical puzzles in finance with ambiguity aversion it is not a given that individual ambiguity attitudes survive in markets in fact despite ample evidence of ambiguity aversion in individual decision making most studies find no or only limited ambiguity aversion in experimental financial markets even when they exclude arbitrage we argue that ambiguity effects in markets depend on market feedback and on a sufficiently strong bias toward ambiguity among the participants accordingly we find significant ambiguity effects in low feedback call markets for assets that provoke high ambiguity aversion but no ambiguity effects in high feedback double auctions

is it worthwhile to pay referees there are puzzles in refereeing scholarly articles why are referees willing to review a paper without payment and is it worthwhile to pay referees in order to raise the review rate two interesting results are found in this article first when reviewing services are driven by reciprocity the equilibrium participation of referees may exhibit the so called self fulfilling feature second the optimal payment may not be zero if the referee receives the benefit of reputation gained by refereeing an article in particular this article will show that those journals whose status quo review rate is lower tend to pay reviewers more while journals whose status quo review rate is higher do not find it worthwhile to pay referees enough this result implies that in order to raise its quality a journal with a low review rate is more likely to adopt a strategy to increase pay and attract a critical mass of referees

disagreement and asset prices abstract how do differences of opinion affect asset prices do investors earn a risk premium when disagreement arises in the market despite their fundamental importance these questions are among the most controversial issues in finance in this paper we use a novel data set that allows us to directly measure the level of disagreement among wall street mortgage dealers about prepayment speeds we examine how disagreement evolves over time and study its effects on expected returns return volatility and trading volume in the mortgage backed security market we find that increased disagreement is associated with higher expected returns higher return volatility and larger trading volume these results imply that there is a positive risk premium for disagreement in asset prices we also show that volatility in and of itself does not lead to higher trading volume instead only when disagreement arises in the market is higher uncertainty associated with more trading finally we are able to distinguish empirically between two competing hypotheses regarding how information in markets gets incorporated into asset prices we find that sophisticated investors appear to update their beliefs through a rational expectations mechanism when disagreement arises

value at risk estimation with the optimal dynamic biofuel portfolio abstract in the past petroleum companies only paid attention to hedging the variation in the crude oil price and volatility however they have now expanded their analysis to encompass renewable sources such as corn and soybeans under the current low carbon biofuel obligations this paper employs garch 1 1 and arji models to estimate the one day ahead value at risk var of the optimal dynamic biofuel portfolio which consists of crude oil corn and soybeans the optimal blended standard is subject to the dual limitations of minimum production costs and the lowest biofuel using requirements our empirical findings confirm that the arji model is more suitable than the garch 1 1 model and further captures the discontinuous jump behavior from the in the sample data the results of out of sample forecasts also are represented that our models play important roles in var estimation and risk management for biofuel portfolio we therefore suggest that the petroleum companies should simultaneously pay attention to jump risk in hedging material costs in the prices of energy related crops

the performance of composite forecast models of value at risk in the energy market this paper examines a comparative evaluation of the predictive performance of various value at risk var models in the energy market this study extends the conventional research in literature by proposing composite forecast models for applying to brent and wti crude oil prices forecasting techniques considered here include the ewma stable density kernel density hull and white garch gpd plus composite forecasts from linearly combining two or more of the competing models above findings show hull and white to be the most powerful approach for capturing downside risk in the energy market reasonable results are also available from carefully combining var forecasts

estimating value at risk of crude oil price and its spillover effect using the ged garch approach estimation has been carried out using garch type models based on the generalized error distribution ged for both the extreme downside and upside value at risks var of returns in the wti and brent crude oil spot markets furthermore according to a new concept of granger causality in risk a kernel based test is proposed to detect extreme risk spillover effect between the two oil markets results of an empirical study indicate that the ged garch based var approach appears more effective than the well recognized hsaf i e historical simulation with arma forecasts moreover this approach is also more realistic and comprehensive than the standard normal distribution based var model that is commonly used results reveal that there is significant two way risk spillover effect between wti and brent markets supplementary study indicates that at the 99 confidence level when negative market news arises that brings about a slump in oil price return historical information on risk in the wti market helps to forecast the brent market conversely it is not the case when positive news occurs and returns rise historical information on risk in the two markets can facilitate forecasts of future extreme market risks for each other these results are valuable for anyone who needs evaluation and forecasts of the risk situation in international crude oil markets

open access and academic journal quality ing from complicated signaling behavior by informed authors lerner and tirole show that adding upstream private information does not alter their basic analysis their proposition 4 454 aea papers and proceedings may 2005

comparison of historically simulated var evidence from oil prices abstract cabedo and moya cabedo j d moya i 2003 estimating oil price value at risk using the historical simulation approach energy economics 25 239 253 find that arma with historical simulation delivers var forecasts that are superior to those from garch we compare the arma with historical simulation to the semi parametric garch model proposed by barone adesi et al barone adesi g giannopoulos k vosper l 1999 var without correlations for portfolios of derivative securities journal of futures markets 19 5 583 602 the results suggest that the semi parametric garch model generates var forecasts that are superior to the var forecasts from the arma with historical simulation this is due to the fact that garch captures volatility clustering our findings suggest that cabedo and moya s conclusion is mainly driven by the normal distributional assumption imposed on the future risk structure in the garch model

does opec influence crude oil prices testing for co movements and causality between regional crude oil prices using high frequency data the co movements among crude oil prices are analysed in order to address the question of regionalization of the world crude oil market time series econometrics in the form of error correction modelling is applied for daily crude oil price data covering the time period 1988 to 2004 and in this framework topics like weak and strong exogeneity among three major oil prices represented by brent opec and texas wti are addressed the empirical results are that causality is most likely bi directional among these crude oil prices and hence rejecting a regionalization hypothesis of the global oil market and also an influence from the opec oil price towards bent and wti which are usually claimed to have a benchmark role

effects of financial innovations on market volatility when beliefs are heterogeneous abstract consider a model with two logarithmic utility maximizer agents that observe aggregate consumption but disagree about its expected rate of change markets are incomplete we first show that volatility of the interest rate in an economy with additional information is higher in a complete markets economy with no additional information there are two differences in volatility with the previous the first one due to the increase in volatility of the wealth share of the individuals is always positive the second difference is the change in covariance between the components of the interest rate volatility and can be positive or negative

evolving standards for academic publishing a q r theory this paper develops models of quality standards to examine two trends academic journals increasingly require extensive revisions of submissions and articles are becoming longer and changing in other ways papers are modeled as varying along two quality dimensions q reflects the importance of the main ideas and r other aspects of quality observed trends are regarded as increases in r quality a static equilibrium model illustrates comparative statics explanations a dynamic model in which referees with a biased view of their own work learn social norms for weighting q and r is shown to produce a long gradual evolution of social norms

analyzing the analysts career concerns and biased earnings forecasts this paper examines the career concerns of security analysts we relate long histories of their earnings forecasts to job separations we find that relatively accurate past forecasts lead to favorable career outcomes such as remaining at or moving up to a high status large prestigious brokerage house controlling for accuracy optimistic forecasts relative to the consensus increase the chances of favorable job separations job separations depend much less on accuracy for analysts who cover stocks that are underwritten by their brokerage houses such analysts are also much more likely to be rewarded for optimistic forecasts than other analysts furthermore job separations were much less sensitive to accuracy and somewhat more sensitive to optimism during the stock market mania of the late 1990s these findings suggest that the well documented analyst forecast optimism bias is likely due to incentives to promote stocks

introduction to the stability of rational expectations equilibrium abstract this paper surveys the literature which examines the stability of the expectations that agents are assumed to have in a rational expectations equilibrium ree this issue is more complex than the usual statistical estimation problem because the relationship between observable variables and payoff relevant variables is endogenous one approach taken in the literature yields convergence to a ree but requires agents to have extensive knowledge about the structure and dynamics of the model that prevails while they learn a second approach does not assume that agents have correctly specified likelihood functions and finds that ree may not be stable

is peer review in decline i introduction for the past half century or more peer reviewed journals have played a central role in the evaluation and dissemination of scientific research the internet has enhanced scientific communication in many ways and there is considerable excitement around new institutions for disseminating research 1 a more sobering thought however is that new technologies can also be disruptive this paper begins with some documentation of recent trends in economics publishing roughly the trends involve economists from top ranked departments publishing fewer papers in many top journals this could be a welcome change but is also potentially troublesome one way in which the internet could be disruptive is that it could allow high profile researchers to disseminate their work without subjecting it to peer review which in turn could lead to a broader unraveling of the peer review system the majority of the paper is then devoted to analyses of several additional data sources with the goal of understanding better what may be causing the observed trends the facts part of this paper documents two main facts 1 economists in top ranked departments now publish very few papers in top field journals there is a marked decline in such publications between the early 1990s and early 2000s 2 comparing the early 2000s with the early 1990s there is a decline in both the absolute number of papers and the share of papers in the top general interest journals written by harvard economics department faculty although the second fact just concerns one department i see it as potentially important to understanding what is happening because it comes at a time when harvard is widely regarded i believe correctly as having ascended to the top position in the profession the decline of peer review theory i allude to in the title is that the necessity of going through the peer review process has lessened for high status authors in the old days peer reviewed journals were by far the most effective means of reaching readers whereas with the growth of the internet high status authors can now post papers online and exploit their reputation to attract readers many alternate explanations are possible i focus on four theories the decline in peer review theory and three alternatives 1 the trends could be a consequence of top school authors being crowded out of the top journals by other researchers several such stories have an optimistic message for example there is more talent entering the profession old pro elite biases are being broken down more schools are encouraging faculty to do cutting edge research and the internet is enabling more cutting edge research by breaking down informational barriers that had hampered researchers outside the top schools 2 2 the trends could be a consequence of the growth of revisions at economics journals discussed in ellison 2002a 2002b in this more pessimistic theory highly productive researchers must abandon some projects and or seek out faster outlets to conserve the time now required to publish their most important works 3 the trends could simply reflect that field journals have declined in quality in some relative sense and become a less attractive place to publish this theory is meant to encompass also the rise of new journals which is not obviously desirable or undesirable the majority of this paper is devoted to examining various data sources that provide additional details about how economics publishing has changed over the past decade these are intended both to sharpen understanding of the facts to be explained and to provide tests of auxiliary predictions of the theories two main sources of information are used data on publications and data on citations the publication data include department level counts of publications in various additional journals an individual level dataset containing records of publications in a subset of journals for thousands of economists and a very small dataset containing complete data on a few authors publication records

long range dependence in an emerging stock market s sectors volatility modelling and var forecasting abstractthis study evaluates the sector risk of the qatar stock exchange qse a recently upgraded emerging stock market using value at risk models for the 7 january 2007 18 october 2015 period after providing evidence for true long memory in volatility using the log likelihood profile test of qu and splitting the sample and dth differentiation tests of shimotsu we compare the figarch hygarch and fiaparch models under normal student t and skewed t innovation distributions based on in and out of sample var forecasts the empirical results show that the skewed student t figarch model generates the most accurate prediction of one day var forecasts the policy implications for portfolio managers are also discussed

forecasting volatility of crude oil markets abstract this article investigates the efficacy of a volatility model for three crude oil markets brent dubai and west texas intermediate wti with regard to its ability to forecast and identify volatility stylized facts in particular volatility persistence or long memory in this context we assess persistence in the volatility of the three crude oil prices using conditional volatility models the cgarch and figarch models are better equipped to capture persistence than are the garch and igarch models the cgarch and figarch models also provide superior performance in out of sample volatility forecasts we conclude that the cgarch and figarch models are useful for modeling and forecasting persistence in the volatility of crude oil prices

disagreement and learning dynamic patterns of trade we study volume dynamics when there are disagreements among investors for that purpose we develop a dynamic model in which differences in the interpretation of public information lead to trade we obtain a simple linear equilibrium in closed form in which risk averse agents take into account future trading opportunities when solving for their optimal portfolio allocation using this framework we then study what restrictions on the disagreement process are needed to generate empirically observed patterns in volume and prices we show that having infrequent but major disagreements leads to autocorrelation in volume and correlation between volume and absolute price changes when agents disagree on past news but agree on the interpretation of current news there is learning and the convergence of agents opinions leads to trade

estimating multi period value at risk of oil futures prices abstractin this study we estimate the multi period value at risk var of oil future prices under a generalized autoregressive conditional heteroscedasticity with a skewed t residuals garch st model which is developed to account for the stylized facts of oil futures returns such as serial correlation volatility clustering asymmetry and heavy tails an efficient approximation algorithm based on the moment calibration method is developed to compute the multi period var and the numerical experiments show that the algorithm can yield good approximation quality in the empirical analysis we find that the garch st model can yield superior out of sample performance to a garch normal model or a garch t model especially when measuring the extreme tail risk meanwhile the square root of time rule srtr tends to underestimate the multi period tail risk and cannot produce a better performance than the garch family models

on existence and uniqueness of equilibrium in a class of noisy rational expectations models i study a general class of noisy rational expectations models that nests the standard grossman and stiglitz 1980 and hellwig 1980 models but relaxes the usual assumption of joint normality of asset pay offs and supply and allows for more general signal structures i provide a constructive proof of existence of equilibrium characterize the price function and provide sufficient conditions for uniqueness within the class of equilibria with continuous price functions which are met by both the grossman and stiglitz 1980 models and the hellwig 1980 models with a continuum of investors my solution approach does not rely on the typical conjecture and verify method and i exhibit a number of non normal examples in which asset prices can be characterized explicitly and in a closed form the results presented here open up a broad class of models for applied work to illustrate the usefulness of generalizing the standard model i show that in settings with non normally distributed pay offs shocks to fundamentals may be amplified purely due to learning effects price drifts can arise naturally and the disagreement return relation depends in a novel way on return skewness

the review process in economics is it too fast rewards for publications in good economics journals are very high and submission fees and other monetary costs associated with submitting an existing manuscript are low consequently the editorial delay especially the first response time the time until the first editorial decision by postponing monetary rewards to publication constitutes the major submission cost from the author s perspective reducing the delay will induce many additional submissions of low quality papers to good journals increasing significantly the workload of editors and referees moreover the rejection rate will increase and cause papers to be rejected more times before publication offsetting at least some of the shorter first response times as a result the efforts of many editors to reduce the editorial delay although attracting more submissions to their journals may have adverse effects from a social perspective and the optimal delay might be longer than the current average of four months

modeling and forecasting extreme commodity prices a markov switching based extreme value model abstract we propose a markov switching multifractal peaks over threshold msm pot model to capture the dynamic behavior of the random occurrences of extreme events exceeding a high threshold in time series of returns this approach allows introducing changes of regimes in the conditional mean function of the inter exceedance times i e the time between two consecutive extreme events in order to admit the presence of short and long term memory patterns further through its multifractal structure the msm pot approach is able to capture the typical stylized facts of extreme events observed in financial time series such as temporal clustering of the size of exceedances and temporal behavior of tail thickness we compare the performance of the msm pot model with competing self exciting models and a garch evt approach in an in and out of sample var forecasting exercise based on the extreme returns of six daily commodity futures prices i e brent and wti crude oil cocoa cotton copper and gold empirical results suggest that the var estimates generated by the msm pot model for the returns analyzed produce the most accurate forecasts

volatility regimes asymmetric basis effects and forecasting performance an empirical investigation of the wti crude oil futures market abstract this study employs a flexible regime switching egarch model with student t distributed error terms to investigate whether volatility regimes and basis affect the behavior of crude oil futures returns including the conditional mean variance skewness kurtosis as well as the extent of heavy tailedness the study also examines whether volatility regimes and asymmetric basis effects can improve the forecasting accuracy the main merit of the empirical model is that the basis effect is allowed to be asymmetric and to vary across volatility regimes empirical results suggest that the conditional mean and variance respond to the basis asymmetrically and nonlinearly and that the responses of transition probabilities to the basis are symmetric furthermore the conditional higher moments are sensitive to the absolute value of basis and the heavy tailed characteristic can be greatly alleviated by taking into account the asymmetric basis effects and regime switches finally the regime switches and asymmetric basis effects play decisive roles in forecasting return volatility and tail distribution

learning from prices and the dispersion in beliefs i study whether investors use an asset s price to update their beliefs about its payos i show that in a dynamic economy the relationship between the dispersion in investor beliefs and returnvolume characteristics can be used to empirically answer this question when investors have rational expectations re and condition on the price i show that belief dispersion is positively related to expected returns return volatility and correlation between volume and absolute returns but negatively related to return autocorrelation when investors do not use the price as in a dierence of opinions do model these relationships are reversed i test these predictions using the crosssection of returns volume and analyst forecast dispersion over dierent horizons the results are consistent with the re model at quarterly and longer horizons but reject both models at the monthly horizon i show that a hybrid model with some do investors and some re investors can match the short horizon evidence the empirical results are consistent with the idea that while some investors do not use the price in the short run they increase their conditioning on the price over time

the slowdown in first response times of economics journals can it be beneficial the first response time henceforth frt of economics journals has increased over the last four decades from 1 2 months to 3 6 months the optimal frt however is not zero because the frt deters submission of mediocre papers to good journals and consequently saves valuable time of referees and editors the change in the actual frt is in the same direction as the change in the optimal frt which has increased because of the availability of research on the internet prior to publication and because the costs of refereeing a paper have increased

value at risk estimations of energy commodities via long memory asymmetry and fat tailed garch models abstract in this paper we evaluate the value at risk var and the expected shortfalls for some major crude oil and gas commodities for both short and long trading positions classical var estimations as well as riskmetrics and other extensions to cases considering for long range memory asymmetry and fat tail in energy markets volatility were conducted we computed the var for three arch garch type models including figarch fiaparch and hygarch these models were estimated in the presence of three alternative innovation s distributions normal student and skewed student our results show that considering for long range memory fat tails and asymmetry performs better in predicting a one day ahead var for both short and long trading positions moreover the fiaparch model outperforms the other models in the var s prediction these results present several potential implications for energy markets risk quantifications and hedging strategies

modeling and forecasting crude oil markets using arch type models this study investigates the time varying volatility of two major crude oil markets the west texas intermediate wti and europe brent a flexible autoregressive conditional heteroskedasticity arch model is used to take into account the stylized volatility facts such as clustering volatility asymmetric news impact and long memory volatility among others the empirical results indicate that the intensity of long persistence volatility in the wti is greater than in the brent it is also found that for the wti the appreciation and depreciation shocks of the wti have similar impact on the resulting volatility however a leverage effect is found in brent although both the estimation and diagnostic evaluations are in favor of an asymmetric long memory arch model only the wti models provide superior in the out of sample forecasts on the other hand from the empirical out of sample forecasts it appears that the simplest parsimonious generalized arch provides the best forecasted evaluations for the brent crude oil data

financial markets with trade on risk and return in this paper i develop a model in which risk averse investors possess private information regarding both a stock s expected payoff and its risk these investors trade in the stock and a derivative whose payoff is driven by the stock s risk in equilibrium the derivative is used to speculate on the stock s risk and to hedge against adverse fluctuations in the stock s risk i analyze the derivative price and variance risk premium that arise in this equilibrium and their predictive power for stock returns finally i examine the relationship between prices and trading volume in the stock and derivative received july 31 2017 editorial decision december 3 2018 by editor stijn van nieuwerburgh authors have furnished an internet appendix which is available on the oxford university press web site next to the link to the final published paper online

are delays in academic publishing necessary researchers perpetually complain about long decision lags glenn ellison 2002a b confirms that delays are being longer he suggests an evolving social norm as a possible explanation with more demands made on authors for their work to be published time delays have the additional effect however of limiting the flow of submissions in the absence of time delays and other significant submission costs the best strategy is to start at the most prestigious journal and work down until the article is accepted better journals are unlikely to welcome this the major submission cost is the long and unpredictable length of time spent waiting for a decision ellison notes that time lags are longer for the top five economics journals at around six to eleven months longer than the rest despite the increasing prestige of top journals the number of submissions remains fairly static

risk assessment of oil price from static and dynamic modelling approaches the price gap between west texas intermediate wti and brent crude oil markets has been completely changed in the past several years the price of wti was always a little larger than that of brent for a long time however the price of wti has been surpassed by that of brent since 2011 the new market circumstances and volatility of oil price require a comprehensive re estimation of risk therefore this study aims to explore an integrated approach to assess the price risk in the two crude oil markets through the value at risk var model the var is estimated by the extreme value theory evt and garch model on the basis of generalized error distribution ged the results show that evt is a powerful approach to capture the risk in the oil markets on the contrary the traditional variance covariance vc and monte carlo mc approaches tend to overestimate risk when the confidence level is 95 but underestimate risk at the confidence level of 99 the var of wti returns is larger than that of brent returns at identical confidence levels moreover the ged garch model can estimate the downside dynamic var accurately for wti and brent oil returns

volume volatility and the dispersion of beliefs i examine a two period noisy rational expectations model of a futures market and show that the dispersion of expectations about a weighted average of future prices measures both the additional volatility and the additional expected volume of trade associated with noisy information the role played by dispersion helps clarify several stylized facts concerning volume and price behavior specifically dispersion can be a factor contributing to the positive correlation between volume and absolute price changes and the positive correlation between consecutive absolute price changes article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

daily seasonality in crude oil returns and volatilities abstract in this article we test for the existence of daily seasonality in returns and volatilities of crude oil using a dummy augmented garch specification for the period from may 1987 to october 2013 our key findings are as follows i volatilities on mondays are significantly higher than on all other weekdays providing the important insight that seasonal effects should be considered when forecasting crude oil volatility ii returns on the other hand tend to be lower on mondays than on other weekdays suggesting profitable investment strategies based on this seasonal pattern in fact the analysis of a simple long short trading rule based on the monday effect provides some evidence that it can outperform a passive buy and hold approach however it cannot do so to an extent that is statistically significant iii our seasonality results are fairly robust to the choice of other frequently used garch model variants like garch m tgarch and cgarch

electronic trading system and returns volatility in the oil futures market this paper uses daily brent crude prices to investigate the employment of electronic trading on the returns conditional volatility in the oil futures market after a suitable garch model is established the conditional volatility series are found the bai and perron model is then used to find two significant structural breaks for these conditional volatility series around two implementation dates of electronic trading this result indicates that the change in the trading system has significant impacts on the returns volatility since our estimated second break date is very close to the all electronic trade implementation date moreover the conditional volatility in the all electronic trading period is found to be more dominated by the temporal persistence rather than the volatility clustering effect all these evidence can shed some light for explaining the high relationship between more volatile world oil price and the more popular electronic trade

submission fees and response times in academic publishing both submission fees and response times enable editors to maintain an acceptable refereeing burden by discouraging the submission of articles with low probability of acceptance when authors differ in their ability or willingness to pay submission fees and deal with delays journal quality is maximized under a combination of moderate fees and moderate delays

the economic value of co movement between oil price and exchange rate using copula based garch models article i nfo the us dollar is used as the primary currency of international crude oil trading as such the recent substantial depreciation in the us dollar has resulted in a corresponding increase in crude oil prices in addition oil price and exchange rate returns have been shown to be skewed and leptokurtic and to exhibit an asymmetric or tail dependence structure therefore this study proposes dynamic copula based garch models to explore the dependence structure between the oil price and the us dollar exchange rate more importantly an asset allocation strategy is implemented to evaluate economic value and confirm the efficiency of the copula based garch models in terms of out of sample forecasting performance a dynamic strategy based on the cgarch model with the student t copula exhibits greater economic benefits than static and other dynamic strategies in addition the positive feedback trading activities are statistically significant within the oil market but this information does not enhance the economic benefits from the perspective of an asset allocation decision finally a more risk averse investor generates a higher fee for switching from a static strategy to a dynamic strategy based on copula based garch models

intertemporal asset pricing with heterogeneous beliefs abstract we examine the behaviour of the interest rate asset prices and asset holdings in an economy with heterogeneous rationally updated beliefs about the expected rate of production growth the equilibrium interest rate is a weighted average of the interest rates that would prevail in economies populated by homogeneous agents with the beliefs of the respective agents in the heterogeneous model the weights are given by the fractions of total wealth held financial innovation affects the dynamics of allocations and prices but preserves the aggregate output process and the structure of equilibrium asset prices also display the wealth weighted average characterization journal of economic literature classification numbers c60 d52 d91 g12

differential interpretation of public signals and trade in speculative markets most models of trade in speculative markets assume that agents interpret public information identically we provide empirical evidence on the relation between the volume of trade and stock returns around public announcements and we argue that the evidence is inconsistent with this assumption we then develop a model of trade around public announcements that incorporates differential interpretations and is consistent with the observed volume return relation then we test the standard model of belief revision underlying most models of trade using stock brokerage research analysts earnings forecasts the hypthesis of identical interpretations seems inconsistent with the forecast revisions in these data

value at risk for long and short trading positions in this paper we model value at risk var for daily stock index returns using a collection of parametric models of the arch family based on the skewed student distribution we show that models that rely on a symmetric density distribution for the error term underperform with respect to skewed density models when the left and right tails of the distribution of returns must be modelled thus var for traders having both long and short positions is not adequately modelled using usual normal or student distributions we suggest using an aparch model based on the skewed student distribution to fully take into account the fat left and right tails of the returns distribution this allows for an adequate modelling of large returns defined on long and short trading positions the performances of all models are assessed on daily data for the cac40 dax nasdaq nikkei and smi stock indexes we also compute the expected short fall and the average multiple of tail event to risk measure for the new model

the slowdown of the economics publishing process over the last three decades there has been a dramatic slowdown of the publication process at top economics journals a substantial part is due to journals requiring more extensive revisions various explanations are considered democratization of the review process increases in the complexity of papers growth of the profession and cost and benefit arguments changes in the profession are examined using time series data connections between these changes and the slowdown are examined using paper level data there is evidence for some explanations but most of the slowdown remains unexplained changes may reflect evolving social norms

arch models properties estimation and testing abstract the aim of this survey paper is to provide an account of some of the important developments in the autoregressive conditional heteroskedasticity arch model since its inception in a seminal paper by engle 1982 this model takes account of many observed properties of asset prices and therefore various interpretations can be attributed to it we start with the basic arch models and discuss their different interpretations arch models have been generalized in different directions to accommodate more and more features of the real world we provide a comprehensive treatment of many of the extensions of the original arch model next we discuss estimation and testing for arch models and note that these models lead to some interesting and unique problems there have been numerous applications and we mention some of these as we present different models the paper includes a glossary of the acronyms for the models we describe

forecasting volatility in the biofuel feedstock markets in the presence of structural breaks a comparison of alternative distribution functions abstract the need for research on commodity volatility has grown considerably due to the important role and financialization of commodities in global asset markets this paper examines the volatility forecasting performance of a wide variety of garch based models in the context of biofuel feedstock markets in the presence of structural breaks our sample is also extended to several non renewable energy commodities to evaluate comparatively the volatility forecasting performance across various commodity markets the model specifications allow for different conditional distribution functions in the rolling window estimations a break detection algorithm finds significant evidence of structural breaks in the unconditional variance of all commodity returns under study the out of sample analysis which is based on an up to date model comparison testing procedure reveals that volatility models accommodating structural breaks in the data provide the best volatility forecasts for most cases regarding the relevance of distribution functions the skewed normal distribution dominates in the model confidence sets nevertheless the complex distribution functions do not always outperform simpler ones although true return distribution is asymmetric and heavy tailed

futures based forecasts how useful are they for oil price volatility forecasting oil price volatility forecasts have recently attracted the attention of many studies in the energy finance field the literature mainly concentrates its attention on the use of daily data using garch type models it is only recently that efforts to use more informative intraday data to forecast oil price realized volatility have been made despite all these previous efforts no study has examined the usefulness of futures based models for oil price realized volatility forecasting although the use of such models is extensive for oil price predictions this study fills this void and shows that futures based forecasts based on intra day data provide informative forecasts for horizons that span between 1 day and 66 days ahead more importantly these results hold true even during turbulent times for the oil market such as the global financial crisis of 2007 09 and the oil collapse period of 2014 15

two trees with heterogeneous beliefs spillover effect of disagreement in a model where investors disagree about the fundamentals of two stocks the state price density depends on investor disagreements for both stocks especially the larger stock this implies that disagreement among investors in a large firm has a spillover effect on the pricing of other stocks owned by these investors the pricing effects of investor disagreements crucially depend on the average belief biases empirical findings support the novel model prediction of a disagreement spillover effect and help reconcile some mixed evidence in the literature

belief dispersion in the stock market we develop a dynamic model of belief dispersion with a continuum of investors differing in beliefs the model is tractable and qualitatively matches many of the empirical regularities in a stock price its mean return volatility and trading volume we find that the stock price is convex in cash flow news and increases in belief dispersion while its mean return decreases when the view on the stock is optimistic and vice versa when pessimistic moreover belief dispersion leads to a higher stock volatility and trading volume we demonstrate that otherwise identical two investor heterogeneous beliefs economies do not necessarily generate our main results

individual investor perceptions and behavior during the financial crisis combining monthly survey data with matching trading records we examine how individual investor perceptions change and drive trading and risk taking behavior during the 2008 2009 financial crisis we find that investor perceptions fluctuate significantly during the crisis with risk tolerance and risk perceptions being less volatile than return expectations during the worst months of the crisis investors return expectations and risk tolerance decrease while their risk perceptions increase towards the end of the crisis investor perceptions recover we document substantial swings in trading and risk taking behavior that are driven by changes in investor perceptions overall individual investors continue to trade actively and do not de risk their investment portfolios during the crisis

forecasting crude oil market volatility further evidence using garch class models abstract this paper extends the work of kang et al 2009 we use a greater number of linear and nonlinear generalized autoregressive conditional heteroskedasticity garch class models to capture the volatility features of two crude oil markets brent and west texas intermediate wti the one five and twenty day out of sample volatility forecasts of the garch class models are evaluated using the superior predictive ability test and with more loss functions unlike kang et al 2009 we find that no model can outperform all of the other models for either the brent or the wti market across different loss functions however in general the nonlinear garch class models which are capable of capturing long memory and or asymmetric volatility exhibit greater forecasting accuracy than the linear ones especially in volatility forecasting over longer time horizons such as five or twenty days

estimation of value at risk for energy commodities via fat tailed garch models the choice of an appropriate distribution for return innovations is important in var applications owing to its ability to directly affect the estimation quality of the required quantiles this study investigates the influence of fat tailed innovation process on the performance of one day ahead var estimates using three garch models garch n garch t and garch ht daily spot prices of five energy commodities wti crude oil brent crude oil heating oil 2 propane and new york harbor conventional gasoline regular are used to compare the accuracy and efficiency of the var models empirical results suggest that for asset returns that exhibit leptokurtic and fat tailed features the var estimates generated by the garch ht models have good accuracy at both low and high confidence levels additionally mrsb indicates that the garch ht model is more efficient than alternatives for most cases at high confidence levels these findings suggest that the heavy tailed distribution is more suitable for energy commodities particularly var calculation

speculative equilibrium with differences in higher order beliefs modest differences in higher order beliefs may have large price effects we generalize a standard rational expectations equilibrium model with different information by allowing differences in higher order beliefs investors have possibly different dogmatic beliefs about the mean different dogmatic beliefs about other investors beliefs and so on for higher and higher orders of beliefs even when every investor s first order expectations are unbiased overvaluation results when investors have inconsistent higher order beliefs that their own expectations are more optimistic than average this lack of common knowledge destabilizes prices in an unbounded manner as market liquidity disappears this paper was accepted by gustavo manso finance

conditional volatility and the informational efficiency of the phlx currency options market abstract the relative performance of implied and historical volatility predictors is compared for four exchange rates from 1985 to 1991 for three currencies arch models estimated up to 1989 show that phlx implied volatilities provide specifications for daily conditional variances which can not be significantly improved by using past returns this result is consistent with the informational efficiency of the philadelphia currency options market out of sample forecasts of the average volatility over four week periods are evaluated for 1990 and 1991 once more the implied predictors are superior to historical predictors

forecasting the volatility of crude oil futures using intraday data abstract we use the information in intraday data to forecast the volatility of crude oil at a horizon of 1 66 days using a variety of models relying on the decomposition of realized variance in its positive or negative semivariances part and its continuous or discontinuous part jumps we show the importance of these decompositions in predictive in sample regressions using a number of specifications nevertheless an important empirical finding comes from an out of sample analysis which unambiguously shows the limited interest of considering these components overall our results indicates that a simple autoregressive specification mimicking long memory and using past realized variances as predictors does not perform significantly worse than more sophisticated models which include the various components of realized variance

a model of competitive stock trading volume a model of competitive stock trading is developed in which investors are heterogeneous in their information and private investment opportunities and rationally trade for both informational and noninformational motives i examine the link between the nature of heterogeneity among investors and the behavior of trading volume and its relation to price dynamics it is found that volume is positively correlated with absolute changes in prices and dividends i show that informational trading and noninformational trading lead to different dynamic relations between trading volume and stock returns

forecasting the var of crude oil market do alternative distributions help abstract accurate modeling of the empirical distribution of crude oil market returns is extremely important in estimating risk measures in addition to several commonly used distributions alternative distributions are explored in this study some of which account for the asymmetry and heavy tails simultaneously found in distributions and contain more tail parameters to separately depict the right and left tails when forecasting the value at risk var of crude oil markets during highly volatile periods seven backtests are also conducted to compare the var forecasting accuracy among different distributions the empirical results indicate that a highly volatile environment challenges the commonly used distributions and the four risk models based on commonly used distributions are rejected about 27 to 38 of the time the alternative distributions i e skewed general error distributions sged generalized hyperbolic skewed student t distributions ghst and generalized asymmetric student t gast distributions generally produce more accurate var measurement and gast gives the best measurement accuracy the empirical results imply that risk managers or policymakers should further consider more flexible distributions such as sged ghst or gast in particular when quantifying or managing the risk in turbulent market times

dispersion of financial analysts earnings forecasts and the option model implied standard deviations of stock returns this study examines whether the information implied by simultaneous levels of option and stock prices specifically the implied standard deviation of returns reflects other contemporaneously available information the independent contemporaneous measure considered is the observed dispersion across several financial analysts at a point in time in the forecasts of earnings per share for a given firm the results indicate that implied standard deviations clearly reflect the contemporaneous dispersion in analysts forecasts incrementally i e beyond the information contained in the historical time series of returns various tests of the black scholes option pricing model have appeared in the literature the basic formulation posits the price of a call option to be a function of the simultaneous market price of the underlying stock the instantaneous variance of the stock s rate of return the exercise price and time to maturity of the option and the risk free interest rate studies by black and scholes 2 galai 8 chiras and manaster 4 and macbeth and merville 12 used the formula to explain the observed prices of options to a successful degree in these tests all the information needed by the formula was directly observable except the instantaneous stock return variance which was measured as the time series variance of historical stock returns manaster and rendleman 14 inverted the procedure to calculate implied stock prices and implied standard deviations of stock returns simultaneously and showed that such implied prices contain information regarding equilibrium future stock prices that is not fully reflected in observed stock prices another set of studies see latane and rendleman 11 chiras and manaster 4 schmalensee and trippi 16 among others examined the properties of the implied instantaneous variance or standard deviation of stock returns that falls out of the formula when the values of all remaining variables are supplied in a test of the predictive ability of such implied standard deviations isd s chiras and manaster 4 found that for predicting future actual time series standard deviations fsd s of stock returns the isd s were superior predictors relative

infrequent rebalancing return autocorrelation and seasonality a model of infrequent rebalancing can explain specific predictability patterns in the time series and cross section of stock returns first infrequent rebalancing produces return autocorrelations that are consistent with empirical evidence from intraday returns and new evidence from daily returns autocorrelations can switch sign and become positive at the rebalancing horizon second the cross sectional variance in expected returns is larger when more traders rebalance this effect generates seasonality in the cross section of stock returns which can help explain available empirical evidence

differential information and dynamic behavior of stock trading volume this article develops a multiperiod rational expectations model of stock trading in which investors have differential information concerning the underlying value of the stock investors trade competitively in the stock market based on their private information and the information revealed by the market clearing prices as well as other public news we examine how trading volume is related to the information flow in the market and how investors trading reveals their private information article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

rational expectations difference of opinions and asset pricing this article applies the concept of relative overconfidence the measure of how heavily investors depend on others information to combine the rational expectations equilibrium ree and differenc

factor loading uncertainty and expected returns firm specific information can affect expected returns if it affects investor uncertainty about risk factor loadings we show that a stock s expected return is decreasing in factor loading uncertainty controlling for the average level of its factor loading when loadings are persistent learning by investors can induce time series variation in price dividend ratios expected returns and idiosyncratic volatility even when the aggregate risk premium is constant and fundamental shocks are homoscedastic consistent with our predictions we estimate that average annual returns of a firm with the median level of factor loading uncertainty are 400 to 525 basis points lower than a comparable firm without factor loading uncertainty the author 2012 published by oxford university press on behalf of the society for financial studies all rights reserved for permissions please e mail journals permissions oup com oxford university press

volatility persistence in crude oil markets financial market participants and policy makers can benefit from a better understanding of how shocks can affect volatility over time this study assesses the impact of structural changes and outliers on volatility persistence of three crude oil markets brent west texas intermediate wti and organization of petroleum exporting countries opec between january 2 1985 and june 17 2011 we identify outliers using a new semi parametric test based on conditional heteroscedasticity models these large shocks can be associated with particular event patterns such as the invasion of kuwait by iraq the operation desert storm the operation desert fox and the global financial crisis as well as opec announcements on production reduction or us announcements on crude inventories we show that outliers can bias i the estimates of the parameters of the equation governing volatility dynamics ii the regularity and non negativity conditions of garch type models garch igarch figarch and hygarch and iii the detection of structural breaks in volatility and thus the estimation of the persistence of the volatility therefore taking into account the outliers on the volatility modelling process may improve the understanding of volatility in crude oil markets

forecasting energy market volatility using garch models can multivariate models beat univariate models abstract in this paper we forecast energy market volatility using both univariate and multivariate garch class models first we forecast volatilities of individual assets and find that multivariate models display better performance than univariate models second we forecast crack spread volatility and contrast the performance of multivariate models for two underlyings with the alternative of univariate ones for crack spreads directly our evidence shows that univariate models allowing for asymmetric effects display the greatest accuracy we also discuss the hedging strategy based on multivariate models and its implications for market participants

value at risk models for dutch bond portfolios this study investigates the consequences of dynamics in the term structure of dutch interest rates for the accurateness of value at risk models therefore value at risk measures are calculated using both historical simulation variance covariance and monte carlo simulation methods for a ten days holding period the best results were obtained for a combined variance covariance monte carlo method using a term structure model with a normal distribution and garch specification term structure models with a t distribution or with cointegration performed much worse 2000 elsevier science b v all rights reserved jel classification e43 g28

caviar based forecast for oil price risk abstract as a benchmark for measuring market risk value at risk var reduces the risk associated with any kind of asset to just a number amount in terms of a currency which can be well understood by regulators board members and other interested parties this paper employs a new var approach due to engle and manganelli engle r f manganelli s 2004 caviar conditional autoregressive value at risk by regression quantiles journal of business and economic statistics 22 367 381 to forecasting oil price risk in doing so we provide two original contributions by introducing a new exponentially weighted moving average caviar model and developing a mixed data regression model for multi period var prediction

forecasting oil price realized volatility using information channels from other asset classes motivated from ross 1989 who maintains that asset volatilities are synonymous to the information flow we claim that cross market volatility transmission effects are synonymous to cross market information flows or information channels from one market to another based on this assertion we assess whether cross market volatility flows contain important information that can improve the accuracy of oil price realized volatility forecasting we concentrate on realized volatilities derived from the intra day prices of the brent crude oil and four different asset classes stocks forex commodities and macro which represent the different information channels by which oil price volatility is impacted from we employ a har framework and estimate forecasts for 1 day to 66 days ahead our findings provide strong evidence that the use of the different information channels enhances the predictive accuracy of oil price realized volatility at all forecasting horizons numerous forecasting evaluation tests and alternative model specifications confirm the robustness of our results

information percolation momentum and reversal abstract we propose a joint theory of time series momentum and reversal based on a rational expectations model we show that a necessary condition for momentum to arise in this framework is that information flows at an increasing rate we focus on word of mouth communication as a mechanism that enforces this condition and generates short term momentum and long term reversal investors with heterogeneous trading strategies contrarian and momentum traders coexist in the marketplace although a significant proportion of investors are momentum traders momentum is not completely eliminated word of mouth communication spreads rumors and generates price run ups and reversals our theoretical predictions are in line with empirical findings

market risk in commodity markets a var approach we put forward value at risk models relevant for commodity traders who have long and short trading positions in commodity markets in a 5 year out of sample study on aluminium copper nickel brent crude oil and wti crude oil daily cash prices and cocoa nearby futures contracts we assess the performance of the riskmetrics skewed student aparch and skewed student arch models while the skewed student aparch model performs best in all cases the skewed student arch model delivers good results and its estimation does not require non linear optimization procedures as such this new model could be relatively easily integrated in a spreadsheet like environment and used by market practitioners

security analysts career concerns and herding of earnings forecasts several theories of reputation and herding see e g scharfstein and stein 1990 suggest that herding among agents should vary with career concerns our goal in this paper is to document whether such a link exists in the labor market for security analysts specifically we look at the relationship between an analyst s job tenure a proxy for career concerns and various measures of stock earnings forecast performance we establish the following key results 1 older analysts are more likely to produce earnings forecasts of firms before younger ones 2 their forecasts also deviate more from the consensus forecast than their younger counterparts we argue that these results are consistent with some reputational models of herding we also establish a number of auxiliary findings regarding the relationship between forecast accuracy and frequency of forecast revisions with job tenure

how relevant is volatility forecasting for financial risk management it depends if volatility fluctuates in a forecastable way volatility forecasts are useful for risk management hence the interest in volatility forecastability in the risk management literature volatility forecastability however varies with horizon and different horizons are relevant in different applications moreover existing assessments of volatility forecastability are plagued by the fact that they are joint assessments of volatility forecastability and an assumed model and the results can vary not only with the horizon but also with the assumed model to address this problem we develop a model free procedure for assessing volatility forecastability across horizons perhaps surprisingly we find that volatility forecastability decays quickly with horizon volatility forecastability although clearly of relevance for risk management at the short horizons relevant for say trading desk management may be much less important at longer horizons

volatility forecasting and risk management for commodity markets in the presence of asymmetry and long memory abstract this paper explores the relevance of asymmetry and long memory in modeling and forecasting the conditional volatility and market risk of four widely traded commodities crude oil natural gas gold and silver a broad set of the most popular linear and nonlinear garch type models is used to investigate this relevancy our in sample and out of sample results show that volatility of commodity returns can be better described by nonlinear volatility models accommodating the long memory and asymmetry features in particular the fiaparch model is found to be the best suited for estimating the var forecasts for both short and long trading positions this model also gives for all four commodities the lowest number of violations under the basel ii accord rule given a risk exposure at the 99 confidence level several implications for commodity market risks policy regulations and hedging strategies can be drawn from the obtained results