do complex financial models really lead to complex dynamics agent based models and multifractality abstract agent based models are usually claimed to generate complex dynamics however the link to such complexity has not been subject to rigorous examination this paper studies this link between the complexity of financial time series measured by their multifractal properties and the design of various small scale agent based frameworks used to model the heterogeneity of financial markets nine popular models are analyzed and while some of the models do not generate interesting multifractal patterns we observe the strongest tendency towards multifractal behavior for the bornholdt ising model the discrete choice based models by gaunersdorfer hommes and schmitt westerhoff and the transition probabilities based framework by franke westerhoff complexity is thus not an automatic feature of the time series generated by any agent based model but generated only by models with specific properties in addition because multifractality is considered a financial stylized fact its presence can be used as a new means to validate such models

activist monetary policy under rational expectations the purpose of this paper is to argue that the pursuit of an activist monetary policy may make economic sense even when people s expectations are formed rationally the paper presents a simple model in which 1 prices are costly to adjust 2 there is uncertainty concerning the parameters affecting aggregate demand and 3 there are positive costs of gathering and processing information by reference to this model it can be shown that an activist monetary policy may or may not be useful in offsetting aggregate disturbances depending upon the extent of information costs and of parameter uncertainty

short and long memory in stock returns data the properties of an iterative procedure for the estimation of the parameters of an arfima process are investigated in a monte carlo study the estimation procedure is applied to stock returns data for 15 countries

impact of speculator s expectations of returns and time scales of investment on crude oil price behaviors abstract based on time series of crude oil prices daily spot this paper analyses price fluctuation with two significant parameters speculators time scales of investment and e speculators expectations of return by using zipf analysis technique specifically by mapping returns of prices into 3 alphabeted sequences absolute frequencies and 2 alphabeted sequences relative frequencies containing the fundamental information of price fluctuations this paper empirically explores parameters and identifies various types of speculators cognition patterns of price behavior in order to quantify the degree of distortion a feasible reference is proposed an ideal speculator finally this paper discusses the similarities and differences between those cognition patterns of speculators and those of an ideal speculator the resultant analyses identify the possible distortion of price behaviors by their patterns

continuous cascade models for asset returns abstract in this paper we make a short overview of continuous cascade models recently introduced to model asset return fluctuations we show that these models account in a very parcimonious manner for most of stylized facts of financial time series we review in more details the simplest continuous cascade namely the log normal multifractal random walk mrw it can simply be considered as a stochastic volatility model where the log volatility memory has a peculiar logarithmic shape this model possesses some appealing stability properties with respect to time aggregation we describe how one can estimate it using a gmm method and we present some applications to volatility and var value at risk forecasting

price level determinacy with an interest rate policy rule and rational expectations abstract this paper reconsiders a result obtained by sargent and wallace namely that price level indeterminacy obtains in their model if the monetary authorities adopt a feedback rule for the interest rate rather than the money stock it is shown that the indeterminacy vanishes if the interest rate rule is chosen so as to have a desired effect on the expected quantity of money demanded this holds even if considerable weight is given in the choice of a rule to the aim of smoothing interest rate fluctuations

long term memories of developed and emerging markets using the scaling analysis to characterize their stage of development the scaling properties encompass in a simple analysis many of the volatility characteristics of financial markets that is why we use them to probe the different degree of markets development we empirically study the scaling properties of daily foreign exchange rates stock market indices and fixed income instruments by using the generalized hurst approach we show that the scaling exponents are associated with characteristics of the specific markets and can be used to differentiate markets in their stage of development the robustness of the results is tested by both monte carlo studies and a computation of the scaling in the frequency domain

scaling in economics a reader s guide this paper discusses examples of scaling laws in economics and finance it argues that these regularities in data are useful for disciplining theory formation estimation of the conditional predictive distribution and estimation of impulse response functions is a main goal of econometric work scaling type regularities give useful information on the underlying data generating process the ability of scaling laws to suggest lines of potentially fruitful research was illustrated by the suggestion of several speculative research projects in this paper most importantly the paper stresses the challenges that face empirical and theoretical researchers who wish to make use of scaling law type regularities to improve econometric identification of the underlying causal data generating mechanism copyright 1999 by oxford university press

is there a role for commodity prices in the design of monetary policy some empirical the consumer price index in the united states follows a non trend stationary stochastic process that describes the index as drifting randomly upward without bound monetarists have long pointed to similar properties in the time series of monetary aggregates as the source of this incipient inflation their solution to this problem is close adherence by the central bank to targets for a monetary or reserve aggregate that correspond to slow and steady monetary growth with any periods of excessive monetary growth subsequently offset this would produce monetary series that are trend stationary if the demand for money is reasonably stable price series would also become trend stationary and for properly chosen targets the price level would be bounded with a mean inflation rate of zero

statistical study of foreign exchange rates empirical evidence of a price change scaling law and intraday analysis abstract in this paper we present a statistical analysis of four foreign exchange spot rates against the u s dollar with several million intra day prices over 3 years the analysis also includes gold prices and samples of daily foreign exchange prices over 15 years the mean absolute changes of logarithmic prices are found to follow a scaling law against the time interval on which they are measured this empirical law holds although the distributions of the price changes strongly differ for different interval sizes systematic variations of the volatility are found even during business hours by an intra day analysis of price changes seasonal heteroskedasticity is observed with a period of one day as well as one week as the result of an analogous intra week analysis taking this into account is necessary for any future study of intra day price change distributions and their generating process the same type of analysis is also made for the bid ask spreads

interest rates aggregate information and monetary policy abstract interest rates set on economy wide markets represent an important source of information to economic agents within the class of business cycle models advanced by lucas and barro this paper explores the information conveyed by such aggregate signals and the types of monetary policies that can influence economic activity by changing the information content of interest rates

wealth effects of open market operations and optimal monetary policy abstract equilibrium models of the business cycle such as those developed by lucas 1973 and barro 1976 barro 1980 are often used to analyze the effects of monetary disturbances on the economy these models typically view monetary injections as arising through lump sum transfer payments that are independent of an agent s holdings of money this paper examines the effects caused by misperceptions about money for the more realistic case when money is injected through open market operations the major result is that unperceived open market operations have a negative wealth effect

talent and or popularity what does it take to be a superstar the phenomenon of superstars wherein small numbers of people earn enormous amounts of money and dominate the activities in which they engage seems to be increasingly important in the modern world rosen 1981 845 i introduction this the opening sentence of sherwin rosen s seminal paper the economics of superstars applies today more than ever technological change has increased the scope and the intensity of the so called winner takes all markets in the last decades the central question addressed in this article is what does it take to be a superstar why do some artists media stars professional athletes or executives earn disproportionately high salaries while others receive comparatively low remuneration in the literature there are basically two competing but not mutually exclusive theories of superstar formation proposed by rosen 1981 and adler 1985 1 although sherwin rosen explains how small differences in talent translate into large differences in earnings moshe adler argues that superstars might even emerge among equally talented performers due to the positive network externalities of popularity empirical tests of the different driving forces of superstar salaries have proved to be very difficult because an objective measure of a star s talent is often hard to find and even harder to quantify krueger 2005 for example what characterizes the talent of a pop music star the literature offers different approaches hamlen 1991 1994 uses the physical concept of voice quality which measures the frequency of harmonic content that singers use when they sing the word love in one of their songs but is such a high quality voice really a deciding factor for success in pop music krueger 2005 measures star quality by the number of millimeters of print columns devoted to each artist in the rolling stone encyclopedia of rock roll nevertheless as he admits this measure reflects the subjective importance the editors of the encyclopedia implicitly devote to each artist which may correlate both with the artist s talent and with his her popularity in team settings the difficulty of accurately measuring star talent is even greater as individual contributions to team output are mostly unclear however the empirical relevance of stars within teams is undoubted star ceos in top management teams lead singers of rock bands and star athletes on sports teams are just a few examples of superstars embedded in teams this article argues that rank order tournaments in professional sports allow a more accurate determination of talent than in the arts even though each athlete s performance is also affected by random events luck or other factors like weak fitness in individual sports it can typically be assumed that the most talented athlete enjoys the highest probability of winning as we examine superstars in a team setting namely in professional soccer we first estimate a team production function to identify the playing characteristics that significantly influence the probability of a team winning to do so we use the detailed statistics of the opta sports data company which counts and classifies every touch of the ball during the game by each player in a second step we use the individual performance statistics of all variables that have proved to be critical for winning as indicators of the player s talent we estimate the impact of talent popularity and various controls on the player s market value employing individual panel data from the highest german soccer league a player s popularity is measured by the annual press publicity he receives in over 20 different newspapers and magazines purged of the positive influences of on field performance so that our popularity indicator captures the nonperformance related celebrity status of a player we find empirical evidence that both talent and nonperformance related popularity increase the market values of soccer stars

is there an operational interest rate rule in his 1983 paper jeremy siegel derives a seemingly implementable policy rule involving optimal responses to interest rates the existence of such a rule would be of tremendous interest to central banks whose monetary policies place heavy weight on responses to interest rates the siegel rule is especially appealing because it is i an optimal combination policy in the sense of william poole 1970 and ii the proposed implementation of the rule does not require detailed knowledge of the structure of the economy all that is required is a calculation of the covariance between innovations in prices and interest rates within the confines of a rational expectations equilibrium model in which siegel assumes agents do not make use of information embodied in the current nominal interest rate he is able to design an optimal combination policy that does not require detailed information about the economy that such an optimal policy exists is not new but that it can be easily implemented is novel the policy rule depends solely on the covariance between innovations in the aggregate price level and innovations in the nominal rate of interest normalized by the variance of innovations in the interest rate when this index is zero policy has been set optimally when the index is positive the feedback term on interest rates in the money supply rule is too large and when the index is negative the feedback term is too small given that one can obtain reduced form expressions for prices and interest rates the index is easily computed unfortunately siegel s proposal violates robert lucas s 1976 critique that is he implicitly treats as invariant certain aspects of economic behavior that will generally change when one moves to an operational interest rate rule this note shows in detail that in a model where prices are flexible and agents observe local market prices i e the model at least employed verbally by siegel that the coefficients in the aggregate supply and demand functions are not invariant to the form of the money supply rule this lack of invariance will cause siegel s rule to be nonoperational the sensitivity of parameters in aggregate supply functions to policy is not restricted to equilibrium models with flexible prices this property also extends to contracting models with endogenous indexing see for example jo anna gray 1976 therefore siegel s rule will not be implementable in a wide variety of commonly used macro models

monetary policy and the information content of prices rational expectations and cleared markets lead to the proposition that feedback monetary policy is irrelevant to real activity as in the analyses of sargent and wallace however if agents are differentially informed and have access to a common price then prospective monetary policy actions future feedback to imperfectly known current circumstances can alter real activity by changing the information content of prices

why the long term auto correlation has not been eliminated by arbitragers evidences from nymex abstract the efficient market hypothesis claims that market prices follow the random walk and that any predictable trend will be eliminated by arbitragers in a short period of time however the fractal market hypothesis disagrees asserting that long term memory can persist in the market to understand why this conflict exists we propose a method to explore the long term market trend using the local hurst exponent and seek to obtain the extra yield performance is evaluated by using both a simulation and the high frequency 5 min data and the daily data the result indicates that the model performs well with the uni fractal series in the simulation however the model shows limited predictive abilities with the data from the real market due to the multi fractal characteristics although the long term trends persist in the markets and can be identified with statistical significance traders cannot beat the market because of the time varying feature and because the strength of long term memory is not strong enough to cover the transaction costs the result reconciles the long term auto correlations with emh in a quantitative manner

the relationships between petroleum and stock returns an asymmetric dynamic equi correlation approach in this paper we propose an asymmetric dynamic equi correlation adeco model to investigate the correlations between returns of petroleum futures and stock indices our adeco reveals the in sample significant asymmetric effect in oil stock correlations to evaluate out of sample performance we consider a portfolio with petroleum futures and stocks in which the weights are determined by forecasts of covariance matrix we find that adeco provides portfolios with better performances than existing popular deco dcc and adcc models in the minimum variance framework moreover energy price risk can be better hedged by stocks in oil exporting countries than stocks in oil importing countries our findings are further demonstrated to be robust to the change of futures maturity

time varying long range dependence in energy futures markets abstract this study aims to investigate the presence of long range dependence in energy futures markets using a daily dataset covering from 1990 to 2013 which includes crucial events for energy markets such as invasion of iraq and global financial crisis of 2008 we estimate time varying generalized hurst exponents of several energy futures contracts with different times to maturity using a rolling window approach results reveal that efficiency of energy futures markets is clearly time varying and changes drastically over the sample period for futures contracts with 1 4 months to maturities crude oil and gasoline are found to be more efficient compared to others on the other hand for contracts with 5 9 months to maturities crude oil and natural gas futures are more efficient for almost every different month to maturity heating oil and gas oil futures are found to be the least efficient markets moreover in general the efficiency of energy futures markets is found to be decreasing dramatically when time to maturity is increasing several implications are discussed

commodity futures and market efficiency we propose a comprehensive treatment of the leverage effect i e the relationship between returns and volatility of a specific asset focusing on energy commodities futures namely brent and wti crude oils natural gas and heating oil after estimating the volatility process without assuming any specific form of its behavior we find the volatility to be long term dependent with the hurst exponent on a verge of stationarity and non stationarity to overcome such complication we utilize the detrended cross correlation and the detrending moving average cross correlation coefficients and we find the standard leverage effect for both crude oils and heating oil for natural gas we find the inverse leverage effect additionally we report that the strength of the leverage effects is scale dependent finally we also show that none of the effects between returns and volatility is detected as the long term cross correlated one these findings can be further utilized to enhance forecasting models and mainly in the risk management and portfolio diversification

monetary instruments and policy rules in a rational expectations environment abstract this paper explores the implications of rational expectations and the aggregate supply theory advanced by lucas 1973 and barro 1976 for analysis of optimal monetary policy under uncertainty along the lines of poole 1970 returning to a topic initially treated by sargent and wallace 1975 not surprisingly these two classical concepts alter both the menu of feasible policy choice and the desirability of certain policy actions in our setup unlike that of sargent and wallace 1975 the systematic component of monetary policy is a relevant determinant of the magnitude of business fluctuations that arise from shocks to the system central bank behavior both the selection of monetary instruments and the framing of overall policy response to economic conditions can work to diminish or increase the magnitude of business fluctuations however the activist policies stressed by the present discussion bear little if any relationship to the policy options rationalized by the conventional analysis of monetary policy under uncertainty in particular in contrast to poole s analysis money supply responses to the nominal interest rate are not important determinants of real economic activity rather the central bank should focus on policies that make movements in the general price level readily identifiable by economic agents