optimal consumption and investment with transaction costs and multiple risky assets we consider the optimal intertemporal consumption and investment policy of a constant absolute risk aversion cara investor who faces fixed and proportional transaction costs when trading multiple risky assets we show that when asset returns are uncorrelated the optimal investment policy is to keep the dollar amount invested in each risky asset between two constant levels and upon reaching either of these thresholds to trade to the corresponding optimal targets an extensive analysis suggests that transaction cost is an important factor in affecting trading volume and that it can significantly diminish the importance of stock return predictability as reported in the literature this paper studies the optimal intertemporal consumption and investment policy of an investor with a constant absolute risk aversion cara preference and an infinite horizon the investor can trade in one risk free asset and n 1 risky assets in contrast to the standard setting the investor faces both fixed and proportional transaction costs in trading any of these risky assets in the absence of transaction costs and when risky asset prices follow geometric brownian motions the optimal investment policy is to keep a constant dollar amount in each risky asset as shown by merton 1971 this trading strategy requires continuous trading in all the risky assets in addition the optimal consumption is affine in the total wealth in the presence of transaction costs however trading continuously in a risky asset would incur infinite transaction costs therefore risky assets are traded only infrequently in this case the literature on optimal consumption and investment with multiple risky assets subject to transaction costs is limited leland 2000 examines a multiasset investment fund that is subject to transaction costs and capital gains taxes under the assumption that the fund has an exogenous target for each risky asset he develops a relatively simple numerical procedure to compute the no transaction region akian menaldi and sulem 1996 consider an optimal consumption and investment problem with proportional transaction costs for

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

the effect of inflation targeting on the behavior of expected inflation evidence from an 11 country panel abstract inflation targets were introduced in the 1990s in australia canada new zealand sweden and the united kingdom change in the behavior of expected inflation in the five targeting countries is measured in a panel that includes six non targeting countries france germany italy the netherlands japan and the united states the level of expected inflation in targeting countries falls after the announcement of targets with controls for country effects year effects ongoing inflation reduction and the business cycle neither the variability of expected inflation nor the average absolute forecast error falls after the announcement of targets with controls for the level and variability of past inflation both targeting and non targeting countries experience unexpected disinflation

what is fractional integration a simple construction that will be referred to as an error duration model is shown to generate fractional integration and long memory an error duration representation also exists for many familiar arma models making error duration an alternative to autoregression for explaining dynamic persistence in economic variables the results lead to a straightforward procedure for simulating fractional integration and establish a connection between fractional integration and common notions of structural change two examples show how the error duration model could account for fractional integration in aggregate employment and in asset price volatility

smooth trading with overconfidence and market power we describe a symmetric continuous time model of trading among relatively overconfident oligopolistic informed traders with exponential utility traders agree to disagree about the precisions of their continuous flows of gaussian private information with enough disagreement an equilibrium exists in which prices reveal the average of all traders signals immediately but traders continue to trade gradually towards target inventories the price is a linear function of a trader s inventory the derivative of a trader s inventory and the average other traders valuations prices reflect a keynesian beauty contest faster than equilibrium trading generates flash crashes jel d8 d43 d47 g02 g14

the effect of inflation targets on the level of expected inflation in five countries did inflation targets reduce the level of expected inflation in australia canada new zealand sweden and the united kingdom in this note predictions of forecasts by professional forecasters are constructed for five consecutive 12 month periods after the announcement of targets these predictions use a variety of information variables known to forecasters at the time they make their forecasts the results show that after the announcement of targets predicted forecasts are less than actual forecasts in australia canada new zealand and sweden this is evidence that targets reduced the level of expected inflation no evidence of such effects is found in the united kingdom

inflation targeting in emerging market and transition economies lessons after a decade abstract starting in the early 1990s several emerging market and transition economies adopted inflation targeting it in this paper we discuss a number of issues that arise in this context a the definition of it b the role of preconditions for it c the use of intermediate exchange rate targets and d the specification of inflation targets our overall conclusion is that suitably modified it is a useful policy strategy for emes

accessing modern science policy and institutional options for agricultural biotechnology in developing countries the paper highlights the complexity of the challenge in developing forms of collaboration between a variety of actors in the biotechnology area in developing countries national research systems with diverse capacities in biotechnology international research centers local private research and development companies and advanced research institutes in both industrialized and developing countries case studies are provided from strong programs such as india china and brazil which will be tool developers as well as users programs that are developing an adaptive capacity in biotech to use tools and methods in a large number of countries whose research systems have virtually no capacity in molecular biology each type program presents challenges and opportunities for accessing new technologies based on facilitation of private investments public private partnerships and local capacity to design proprietary technologies working with the consultative group on international agricultural research centers as intermediaries and partners and with regional consortia policy and institutional issues for accessing modern science are then discussed and many of the challenges involve developing strategies in intellectual property management while pubic research organizations will need to develop innovative means of segmenting markets to complement private sector interests

dynamic portfolio choice with frictions abstract we show how portfolio choice can be modeled in continuous time with transitory and persistent transaction costs multiple assets multiple signals predicting returns and general signal dynamics the objective function is derived from the limit of discrete time models with endogenous transaction costs due to optimal dealer behavior we solve the model explicitly and the intuitive solution is also the limit of the solutions of the corresponding discrete time models we show how the optimal high frequency trading strategy depends on the nature of the trading costs which in turn depend on dealers inventory dynamics finally we provide equilibrium implications and illustrate the model s broader applicability to micro and macro economics monetary policy and political economy

the near optimality of adaptive expectations abstract rational expectations require more information than adaptive expectations and thus must be more costly in a standard macro model the losses associated with adaptive expectations are shown to be very small indeed even for quite large monetary disturbances as a result adaptive expectations may be close to optimal as long as the monetary regime is relatively stable further with adaptive expectations fully anticipated monetary changes lead to large and persistent fluctuations in aggregate output this is true even if only a very small percentage of firms behave adaptively

anchoring inflation expectations in the face of oil shocks in the proximity of zlb a tale of two targeters this paper applies a n ardl framework to two longstanding inflation targeting policy regimes in order to assess the relation between oil prices dynamics and inflation expectations and the further consequences created by a proximal zlb situation the application is based on data from january 1994 to june 2018 for new zealand and the uk we focus on oil price shocks as a variable of interest and this was found to have an asymmetric effect on inflation expectations one further key finding is that the real effective exchange rate has significant impacts on inflation expectations and this is indicative of an exchange rate pass through to inflation via an inflation expectations channel in general we find that inflation exchange rate money supply output growth unemployment and fiscal deficit surplus have significant implications for inflation expectations inflation expectations are also influenced by their past behaviour indicating adaptive inflation expectations this study contributes to the debate on the inflation targeting at zlb

announcements inflation targeting and central bank incentives this paper studies the incentives a central bank faces in announcing inflation targets when the central bank has private information about the economy and the public is uncertain about the central bank s preferences targeting rules in the absence of announcements reduce the inflationary bias of discretionary policy but they distort the central bank s response to private information about the economy this distortion is eliminated when the central bank is allowed to announce the inflation target announcements also affect credibility although the way they do so depends on the exact definition of credibility that is employed in standard models of monetary policy in which dynamic inconsistency plays a prominent role announcements from the central bank about its policy inten tions are not believable the central bank has an incentive to lie yet central banks often do make announcements and they are legally required to do so in some cases the bank of england for example must issue periodic inflation reports the chairman of the federal reserve is required by the humphrey hawkins act to testify before congress twice each year to explain the fed s policy actions and to detail the fed s outlook for future economic develop ments similarly the reserve bank of new zealand is required under the reserve bank act of 1989 to publish policy statements that spell out its plans the january 1994 legislation governing the banque de france requires its gov ernor to appear before parliament and the european central bank must under the maastricht treaty report at least annually to the european parlia ment if public statements about policy intentions are not credible the question naturally arises as to why central banks are frequently required to make them the answer of course is that announcements do provide the public with some information given the growing interest in policy transparency particu larly among those central banks that have adopted some form of inflation targeting it is perhaps surprising that there has been relatively little explicit analysis of how inflation targeting requirements might combine with reporting requirements to influence the informational content of announcements the conduct of stabilization policies and the central bank s credibility the purpose of this paper is to analyse the way inflation targeting affects the incentives the central bank faces in announcing targets when the central bank has private information about the economy and the public is uncertain about the central bank s preferences inflation targeting has seen increased popularity in recent years but a fixed target for inflation is generally suboptimal in the face of supply shocks while state contingent targets are viewed as not feasible an important result of this paper is that allowing the central bank to announce its own inflation target

analysing inflation by the fractionally integrated arfima garch model this paper considers the application of long memory processes to describing inflation for ten countries we implement a new procedure to obtain approximate maximum likelihood estimates of an arfima garch process which is fractionally integrated i d with a superimposed stationary arma component in its conditional mean additionally this long memory process is allowed to have garch type conditional heteroscedasticity on analysing monthly post world war ii cpi inflation for ten different countries we find strong evidence of long memory with mean reverting behaviour for all countries except japan which appears stationary for three high inflation economies there is evidence that the mean and volatility of inflation interact in a way that is consistent with the friedman hypothesis

farmer participation in supermarket channels production technology and efficiency the case of vegetables in kenya supermarkets are gaining ground in agrifood systems of many developing countries while recent research has analyzed income effects in the small farm sector impacts on productivity and efficiency have hardly been studied we use a meta frontier approach and combine this with propensity score matching to estimate treatment effects among vegetable farmers in kenya participation in supermarket channels increases farm productivity in terms of meta technology ratios by 45 we also find positive and significant impacts on technical efficiency and scale efficiency supermarket expansion therefore presents opportunities for agricultural growth in the small farm sector which is crucial for poverty reduction in africa copyright 2012 oxford university press

asset prices and liquidity in an exchange economy i develop an asset pricing model in which financial assets are valued for their liquidity the extent to which they are useful in facilitating exchange as well as for being claims to streams of consumption goods the implications for average asset returns the equity premium puzzle and the risk free rate puzzle are explored in a version of the model that nests the work of mehra and prescott 1985

long memory in inflation rates international evidence we examine monthly inflation rates of five industrial countries the application of tests against stationarity as well as tests against a unit root yield contradictory results thus fractional integration allowing for long memory is a plausible model we discuss and apply the periodogram regression to estimate the difference parameters for all countries we find estimates significantly different from 1 as well as from 0 this is evidence in favor of long memory specification tests and maximum likelihood estimates support the fitted models finally we relate our empirical results to the construction of the data

long memory and aggregation in macroeconomic time series this paper explores the interaction between long memory and aggregation results are derived which link the possibly fractional orders of integration of the aggregate series with those of the underlying series when the aggregation is either cross sectional or temporal in discrete or continuous time these results provide empirically testable hypotheses that are examined using six u k macroeconomic series a semiparametric method is found to be broadly consistent with the implications of the theory but fully parametric arfima models show considerable variation each series appears to be integrated of an order of between one and one and a half

inflation targeting an indirect approach to assess the direct impact it is quite difficult to assess the benefits of inflation targeting it since its immediate effect will be on inflation expectations an unobserved variable due to lack of comprehensive data on inflation expectations most studies so far concentrated on the impact of it either on observable variables like output unemployment and inflation or compared post it surveys of itcountries with nonit countries in our study we focus on a yet unanswered question i e how the expectations change with the adoption of it we suggest that heterogeneous inflation expectations lead to long memory in actual inflation and it if successful should decrease this persistence by concentrating the public s expectations toward the announced target empirical results confirm our hypothesis with a reduction in inflation memory after the adoption of it in almost all eight developed countries in our sample

modeling long run behavior with the fractional arima model abstract when modeling long run behavior fractional arima models can give insights unobtainable with the nonfractional arima models as an application the deterministic trend and unit root with drift models are nested in the fractional arima model this allows testing between the two models based on estimated parameter values this test is applied to postwar us quarterly real gnp the test concludes that gnp is consistent with both models the estimated fractional parameter is significantly smaller than reported in diebold and rudebusch 1989 the difference is explained by bias in the previous estimates relationships with the cumulative impulse response and spectral density at frequency zero are noted

aggregation persistence and volatility in a macro model we introduce firm heterogeneity into the standard monopolistically competitive real business cycle rbc model the fundamental equilibrium path is derived and the time series properties of aggregate gdp are studied analytically although firms productivities are subject to temporary shocks the aggregate process displays a surprising novel form of nonlinearity and long memory which had not been built into the model at the outset this aggregate gdp turns out to have very different properties from log linear time series models such as auto regressive ar models and their extensions it displays very strong persistence which ends abruptly with a sudden change of tendency giving its autocorrelation function acf an s shape although persistent it is mean reverting unlike the everlasting memory of unit root processes its volatility is of a greater order of magnitude than that of any of its components so small micro shocks can generate large macro fluctuations it is also characterized by long asymmetric cycles of random lengths increased monopoly power tends to reduce the amplitude and increase the

research productivity and output growth in chinese agriculture recent attempts to quantify the sources of growth in chinese agriculture have attributed an exceptionally large share of this growth to the contemporary institutional and market reforms within china to analyze this important issue we use a newly constructed panel data set that includes an agricultural research or stock of knowledge variable our results suggest that while still a significant source of growth the direct growth promoting consequence of institutional change and market reforms have been overstated by these earlier studies research induced technical change accounts for a significant share 20 of the growth in agricultural output since 1965

long memory and structural changes in the forward discount an empirical investigation abstract we analyze the evidence for long memory and structural changes in the five g7 countries forward discount we establish evidence for long memory by estimating the long memory parameter without allowing for structural breaks we also document evidence for multiple structural breaks in the mean of the forward discount we then adjust for structural changes in the forward discount rate and re estimate the long memory parameter after removing the breaks we still find evidence of stationary long memory in each country s forward discount

total factor productivity growth in agriculture a malmquist index analysis of 93 countries 1980 2000 in this paper we examine levels and trends in agricultural output and productivity in 93 developed and developing countries that account for a major portion of the world population and agricultural output we make use of data drawn from the food and agriculture organization of the united nations and our study covers the period 1980 2000 due to the non availability of reliable input price data the study uses data envelopment analysis dea to derive malmquist productivity indexes the study examines trends in agricultural productivity over the period issues of catch up and convergence or in some cases possible divergence in productivity in agriculture are examined within a global framework the paper also derives the shadow prices and value shares that are implicit in the dea based malmquist productivity indices and examines the plausibility of their levels and trends over the study period

rational expectations and macroeconomic forecasts the article presents extensive results from testing for bias and serially correlated errors in a collection of time series of quarterly multiperiod forecasts for six variables including real gnp growth inflation and unemployment the analysis covers responses by 79 frequent participants in economic outlook surveys conducted regularly since 1968 it shows much greater incidence of apparently systematic errors for inflation than for the other variables also the tests are more favorable to composite group forecasts than to most of the individual forecast sets

measurement of hospital efficiency using a latent class stochastic frontier model this article analyses the technical efficiency of portuguese hospitals from 1997 to 2008 with the latent class frontier model enabling the identification of different segments in the cost frontier it is found that there are three statistically significant segments in the sample leading to the conclusion that no common health policy can be applicable to all the hospitals analysed calling rather for policies conceived for each hospital segment identified the health policy based in the identified segments enables a more accurate and cost effective management of resources

inflation targeting and output inflation tradeoffs abstract this article assesses whether the adoption of inflation targeting it helps reduce the output inflation tradeoff we address the self selection problem of it policy adoption by the endogenous switching regressions and show that the output inflation tradeoffs are significantly lower in it countries not only over the whole sample but also across the developed and developing country subsamples in addition we also find strong evidence supporting the positive selection hypothesis i e countries have higher probability of adopting it are exactly those who benefit more larger reduction of output inflation tradeoff from the implementation of it additional results reveal that economies with higher trade openness lower financial openness and less flexible exchange rate regime are associated with larger tradeoff between output and inflation but the effects are only statistically significant in the it regime

inflation targeting a new framework for monetary policy he world s central bankers and their staffs meet regularly in venues from basle to washington to share ideas and discuss common problems perhaps these frequent meetings help explain why changes in the tactics and strategy of monetary policymaking such as the adoption of money growth targets in the 1970s the intensification of efforts to reduce inflation in the 1980s and the recent push for increased institutional independence for central banks tend to occur in many countries more or less simultaneously whatever their source major changes in the theory and practice of central banking are of great importance for both individual countries and the international economy in this article we discuss a new strategy for monetary policy known as inflation targeting which has sparked much interest and debate among central bankers and monetary economists in recent years this approach is characterized as the name suggests by the announcement of official target ranges for the inflation rate at one or more horizons and by explicit acknowledgment that low and stable inflation is the overriding goal of monetary policy other important features of inflation targeting include increased communication with the public about the plans and objectives of the monetary policymakers and in many cases increased accountability of the central bank

portfolio choice and pricing in illiquid markets abstract this paper studies portfolio choice and pricing in markets in which immediate trading may be impossible it departs from the literature by removing restrictions on asset holdings and finds that optimal positions depend significantly and naturally on liquidity when expected future liquidity is high agents take more extreme positions given that they do not have to hold those positions for long when they become undesirable consequently larger trades should be observed in markets with more frequent trading liquidity need not affect the price significantly however because liquidity has offsetting impacts on different agents demands this result highlights the importance of unrestricted portfolio choice the paper draws parallels with the transaction cost literature and clarifies the relationship between the price level and the realized trading frequency in this literature

innovation systems and technical efficiency in developing country agriculture this article examines how different components of an agricultural innovation system interact to determine levels of technical inefficiency in developing country agriculture the analysis draws on data from 85 low and middle income countries for the period 2004 2011 to estimate latent class stochastic frontiers in which the technological class to which the country belongs is determined within the model to enable efficiency comparisons between countries across these technological classes we estimate a meta frontier that encompasses all the class frontiers we embed components of an agricultural innovation systems framework in this estimation to explain countries technical inefficiency with respect to their respective class frontiers mobile phone subscriptions as a measure of institutions that facilitate the transfer of knowledge and information as well as the number of scientific and technical journal articles as a measure of research productivity and knowledge production are found to improve technical efficiency of agricultural production in these countries the mean technical efficiency score of agricultural production between 2004 and 2011 for countries in class one is 44 1 whereas it is 62 7 for countries in class two indicating sizeable potential to improve agricultural production from the same level of agricultural inputs through efficiency enhancing investments

episodic liquidity crises cooperative and predatory trading we describe how episodic illiquidity arises from a breakdown in cooperation between market participants we first solve a one period trading game in continuous time using an asset pricing equation that accounts for the price impact of trading then in a multi period framework we describe an equilibrium in which traders cooperate most of the time through repeated interaction providing apparent liquidity to one another cooperation breaks down when the stakes are high leading to predatory trading and episodic illiquidity equilibrium strategies that involve cooperation across markets lead to less frequent episodic illiquidity but cause contagion when cooperation breaks down why is illiquidity rare and episodic pastor stambaugh 2003 detect only 14 aggregate low liquidity months over the time period 1962 to 1999 despite being of significant magnitude most of the episodes were short lived and were followed by long periods of liquidity 1 the origin of this empirical observation still remains a puzzle in this paper we attempt to shed light on this puzzle by developing a theoretical model in which a breakdown in cooperation between traders in the market manifests itself in predatory trading this mechanism leads to sudden and short lived illiquidity we develop a dynamic model of trading based on liquidity needs during each period a liquidity event may occur in which a trader is required to liquidate a large block of an asset in a relatively short time period this need for liquidity is observed by a tight oligopoly whose members may choose to predate or cooperate predation involves racing and fading the distressed trader to the market

does inflation targeting really make a difference evaluating the treatment effect of inflation targeting in seven industrial countries abstract we evaluate the treatment effect of inflation targeting in seven industrial countries that adopted this policy in the 1990s to address the self selection problem of policy adoption we make use of a variety of propensity score matching methods recently developed in the treatment effect literature our results show that inflation targeting has no significant effects on either inflation or inflation variability in these seven countries further evidence from long term nominal interest rates and income velocity of money also supports the window dressing view of inflation targeting

economically rational expectations equilibrium abstract at the economically rational expectations equilibrium introduced in this paper agents choose between costly rational expectations and costless adaptive expectations we show that the sequence of economically rational expectations equilibria converges to the rational expectations equilibrium and that all agents will ultimately choose adaptive expectations

sectoral systems of innovation and production the concept sectoral system of innovation and production provides a multidimensional integrated and dynamic view of sectors it is proposed that a sectoral system is a set of products and the set of agents carrying out market and non market interactions for the creation production and sale of those products a sectoral systems has a specific knowledge base technologies inputs and demand agents are individuals and organizations at various levels of aggregation they interact through processes of communication exchange co operation competition and command and these interactions are shaped by institutions a sectoral system undergoes change and transformation through the co evolution of its various elements 2002 elsevier science b v all rights reserved

transaction costs and asset prices a dynamic equilibrium model in this article we study the effects of transaction costs on asset prices we assume an overlapping generations economy with a riskless liquid bond and many risky stocks carrying proportional transaction costs we obtain stock prices and turnover in closed form surprisingly a stock s price may increase in transaction costs and a more frequently traded stock may be less adversely affected by an increase in transaction costs calculations based on the marginal investor overestimate the effects of transaction costs for realistic parameter values transaction costs have very small effects on stock prices but large effects on turnover

pricing options in an extended black scholes economy with illiquidity theory and empirical evidence this article studies the pricing of options in an extended black scholes economy in which the underlying asset is not perfectly liquid the resulting liquidity risk is modeled as a stochastic supply curve with the transaction price being a function of the trade size consistent with the market microstructure literature the supply curve is upward sloping with purchases executed at higher prices and sales at lower prices optimal discrete time hedging strategies are then derived empirical evidence reveals a significant liquidity cost intrinsic to every option copyright 2006 oxford university press

announcements and credibility under inflation targeting abstract we inspect how inflation target announcements are instrumental in building central bank credibility and shaping inflation expectations investigating the role of announcements by using a time varying credibility measure we find that both the accuracy and the frequency of inflation announcements have a positive impact on how much attention the public pays to target announcements

why research partnerships really matter innovation theory institutional arrangements and implications for developing new technology for the poor abstract this paper explores the conceptual basis for existing and emergent institutional patterns in the context of partnership approaches to technology development drawing examples from recent studies of private enterprise activity in india smallholder horticulture it suggests that agricultural innovation as a process involves a wider range of organizational types than the conventional policy focus on public sector research organizations would tend to suggest it uses the concept of a national innovation system to argue that a partnership approach is adopted as a core methodology for engaging science and technology development with the livelihood demands of the poor