commodity price shocks and civil conflict evidence from colombia how do income shocks aect armed con ict theory suggests two op posite eects if labor is used to appropriate resources violently higher wages may lower con ict by reducing labor supplied to appropriation this is the opportunity cost eect alternatively a rise in contestable income may increase violence by raising gains from appropriation this is the rapacity eect our paper exploits exogenous price shocks in inter national commodity markets and a rich dataset on civil war in colombia to assess how dierent income shocks aect con ict we examine changes in the price of agricultural goods which are labor intensive and natural resources which are capital intensive we focus on coee and oil the two largest exports we nd that a sharp fall in coee prices in the 1990s increased violence dierentially in regions growing more coee by lower ing wages and the opportunity cost of joining armed groups in contrast a rise in oil prices increased violence dierentially in the oil region by in creasing municipal revenue siphoned through rapacity this pattern holds in several other agricultural and natural resource sectors providing robust evidence that price shocks aect con ict in opposite directions depending on the factor intensity of the commodity

creation adoption and diffusion of innovations by subsidiaries of multinational corporations this paper reports some of the findings of a multi phased and multi method study on the organizational attributes that facilitate creation adoption and diffusion of innovations by subsidiaries of multinational companies comparison of results obtained through case research in nine companies multiple respondent questionnaire surveys in three companies and a single respondent survey in 66 north american and european multinationals reveal unambiguous and positive impacts of normative integration through organizational socialization and dense intra and inter unit communication on an mnc subsidiary s ability to contribute to the different innovation tasks the findings are less consistent with regard to the effects of local resources and autonomy and it appears that the influences of these two attributes are strongly mediated by the levels of normative integration and organizational communication

how labour market flexibility affects unemployment long term implications of the chain reaction theory this paper evaluates two theories of unemployment the natural rate theory whereby unemployment is depicted as fluctuating around a reasonably stable natural rate and the chain reaction theory which views movements in unemployment as the outcome of the interplay between labour market shocks and a network of lagged adjustment processes we show that for labour market systems with two common characteristics lagged endogenous variables and growing exogenous variables lags affect unemployment not only in the short run but in the long run as well the reason is that in the presence of growing exogenous variables the lagged responses are never able to work themselves out entirely in this respect the chain reaction theory contrasts sharply with the natural theory which commonly views unemployment as approaching a natural rate determined solely by the values of the exogenous variables the policy implications of the two theories are quite different as well for an empirical model of the uk market we show that unemployment does not converge to the natural rate as conventionally defined furthermore we show that lagged adjustment processes account for a substantial part of the uk long run equilibrium unemployment rate and for the movement of uk unemployment over the past 15 years this abstract was borrowed from another version of this item

internal cocaine trafficking and armed violence in colombia this paper exploits time variations in international cocaine prices and potential trafficking routes within colombia to estimate the effect of the illegal cocaine trade on changes in municipality homicide rates i construct the potential internal cocaine trafficking network and exploit the fact that different regions in colombia have comparative advantages in serving different international markets my results suggest that when cocaine prices increase in either the united states or europe homicide rates increase in municipalities strategically placed to serve each international market jel d74 k42 f19

uniqueness of equilibrium in the classical capital asset pricing model general equilibrium in the classical two period mean variance capital asset pricing model is not unique corresponding to one single set of expectations utility functions and an initial wealth distribution there may be several equilibria and an asset may have different prices expected rates of return and betas in different equilibria however any equilib rium portfolio is sustained by a unique price system and if investors have decreasing risk aversion then any equilibrium allocation ofthe risky assets is sustained by a unique price system tion of the market portfolio of risky assets the other is the simple linear pricing relation expressed in terms of betas and rates of return by sharpe 1964 and in terms of prices by lintner 1965 these properties of equilibrium imply severe restrictions on the possible equilibrium portfolios and equilibrium asset prices and they have led to a presumption that the equilibrium in this model is unique see e g sharpe 1970 relying on mossin s 1966 interpretation ofthe model this paper shows that general equilibrium in the classical capm is not necessar ily unique there may be several equilibria even with the same expected total returns covariances utility functions and initial distribution ofthe assets an asset may have different prices expected rates of return and betas in different equilibria however if just one investor s equilibrium holdings of both the risk less and the risky assets are given then the price system is unique if investors have decreasing risk aversion then the price system is unique given the equilib rium allocation of the risky assets on the other hand if investors do not have decreasing risk aversion then an allocation of risky assets may be sustained by several different price systems

asset market equilibrium with short selling this paper presents simple conditions and a simple proof of the existence of equilibrium in asset markets where short selling is allowed and satiation is possible unlike standard non satiation assumptions the one used here is weak enough to be reasonable in the mean variance capital asset pricing model and in asset market models where investors maximize expected utility and where total returns to individual assets may be negative this paper analyses the existence of equilibrium in exchange economy models where choice sets may be unbounded below and satiation is likely there are two main examples of such models one is an asset market model where investors maximize expected utility and the total return to individual assets may be negative with positive probability the other is the mean variance capital asset pricing model capm where investors do not necessarily maximize expected utility but instead maximize a function of only the mean and variance of return to their portfolios in both of these models the investors choice sets will be unbounded if short selling is allowed to short sell a share of an asset means to borrow it and sell it promising to buy it back and return it to the lender at a later date formally short selling corresponds to holding a negative number of shares if unlimited short selling is allowed then there is no limit to how large negative numbers of shares can be held and therefore the choice sets are unbounded satiation can also occur both in the mean variance model and in the expected utility model unless there is a riskless asset in the expected utility model there may be satiation if the individual assets have negative returns with positive probability as the investor gets more and more shares the potential positive returns get larger and larger but so do the potential negative returns if the investor is very averse to large negative returns then he may eventually be satiated and not want any more shares in the mean variance model the expected return to an investor s portfolio increases as he holds more and more shares of the assets but so does the variance of return it may be that at some point the additional expected return gained from adding more shares to the portfolio is not sufficient to compensate for the increase in variance if so then there will be satiation satiation in the mean variance model iie analysed in nielsen 1987 1988 the expected utility model with short selling has been used in many specific analyses of portfolio selection and asset pricing to name but one connor 1984 studies arbitrage pricing in a general equilibrium model where there are no short sales restrictions the mean variance capm is of course very prominent in the finance literature because the

product innovation a tool for competitive advantage abstract this paper assesses the overall contribution of product innovation to competitive advantage analyzes the conditions under which such a contribution is likely and discusses how this likelihood can be increased through company action it concludes that pioneering is not riskier than following and that successful pioneers enjoy substantial and lasting competitive advantages success depends on the innovation s relative advantage compatibility complexity and the strength of the accompanying marketing effort lead time allows pioneers to build up resources that contribute to sustainability but customer and technological changes may destroy the competitive value of these resources

asset stock accumulation and sustainability of competitive advantage given incomplete factor markets appropriate time paths of flow variables must be chosen to build required stocks of assets that is critical resources are accumulated rather than acquired in strategic factor markets barney barney j 1986 strategic factor markets expectations luck and business strategy management sci october 1231 1241 sustainability of a firm s asset position hinges on how easily assets can be substituted or imitated imitability is linked to the characteristics of the asset accumulation process time compression diseconomies asset mass efficiencies inter connectedness asset erosion and causal ambiguity

spatial competition and the core models of spatial competition have proven useful in describing differentiated product markets a serious problem is the nonexistence of nash equilibria this problem is resolved by modelling the price formation process using the core the equilibrium is the outcome of a two stage process in the first stage two firms choose locations simultaneously the second stage has prices determined by an allocation in the core of a cooperative subgame allowing for coalitions of buyers and sellers these prices approach the competitive level as the distance between the firms goes to zero thus capturing the essence of duopoly rivalry this abstract was borrowed from another version of this item

international commodity prices growth and the outbreak of civil war in sub saharan africa to learn more about the effect of economic conditions on civil war we examine whether sub saharan civil wars are more likely to start following downturns in the international price of countries main export commodities the data show a robust effect of commodity price downturns on the outbreak of civil wars we also find that sub saharan countries are more likely to see civil wars following economic downturns in their main oecd export destinations

not only nokia what finland tells us about new economy growth new economy growth is there a relation between information technologies and the growth rate of productivity is this relation mainly due to the efficiency enhancing effects of few leading industries or rather to the pervasive spreading of it throughout the economy our country study on finland in the 1990s is a contribution to shed light on these issues we find that nokia the world leader in cellular phone production directly and substantially contributed to enhance productivity growth in finland productivity growth gains outside nokia and few other it related service industries have been small temporary or non existent at all though we also provide two pieces of evidence against the existence of technological spillovers between nokia and the other fast growing industries in the finnish economy as shown by the finnish input output table the thinness of the inter industry linkages between the nokia industry and the rest of the economy indicates that productivity gains of the size recorded in the few other fast growing service industries can be associated to nokia s productivity boom only to a very small extent parallel statistical analysis also shows a striking association between the timing and the industry distribution of productivity gains and the declining pace of the price of machinery and equipment investment goods in those industries this is evidence that tfp growth increases in those industries should be mostly attributed to the decline in the world price of computing power altogether we interpret our findings as showing that even in a country endowed with a world class national champion and a policy environment commonly thought of as conducive to growth a new economy takes a long time to show up unlike commonly held tenets it diffusion has shown a limited potential in speeding up this process in finland francesco daveri and olmo silva

modelling cost structure the bell system revisited this paper analyses a recent public policy decision and the crucial role played by the choice of the functional form the break up of the bell system is indeed a classic case of anti trust settlement and constitutes one of the most prominent and controversial applications of microeconomics to public policy it is argued that demanding multi output cost properties such as economies of scope for this is the considerable robustness problem displayed by the tranlog cost functional form the reason for this is the considerable able to robustness problem displayed by the translog cost function which is the source underlying many of the expert disagreements it is suggested that the non robustness is due to what ils termed the flip flop property and it is shown that the available empirical evidence from the pre divestiture bell system supports this argument to obtain robust results we propose that the analysis is constrained to the proper region of the cost function we propose that the analysis is con

unemployment wage bargaining and capital labour substitution many economists believe that capital accumulation technical progress and labour force expansion have no lasting effect on unemployment this view rests on the empirically doubtful assumption that the elasticity of substitution between labour and capital is equal to unity i e production is cobb douglas using a simple model based on the work of layard nickell and jackman this paper demonstrates that with a lower elasticity of substitution the equilibrium unemployment rate is affected by all of the above factors it considers briefly how capital accumulation may be endogenised and what long run implications this has for unemployment copyright 1999 by oxford university press

organized crime corruption and punishment we analyze an oligopoly model in which differentiated criminal organizations globally compete on criminal activities and engage in local corruption to avoid punishment when bribing costs are low that is badly paid and dishonest law enforcers work in a weak governance environment and the rents from criminal activity are sufficiently high we find that increasing policing and sanctions can generate higher crime rates indeed beyond a threshold further increases in intended expected punishment create incentives for organized crime to extend corruption rings and ensuing impunity results in a fall of actual expected punishment that yields more rather than less crime

capital accumulation and unemployment new insights on the nordic experience this paper takes a fresh look at the analysis of labour market dynamics and argues that capital accumulation plays a fundamental role in shaping unemployment movements this role has generally been examined by considering indirect transmission channels of the capital stock effects i e using variables like interest rates or investment ratios in the estimation of single equation unemployment rate models here we advocate a different approach we directly estimate the effects of capital stock in the labour market by applying the chain reaction theory of unemployment and we find that capital stock is a major determinant of unemployment in the nordic countries in particular the different unemployment experiences of these economies derive from the temporary albeit prolonged negative shocks to capital stock growth in denmark and sweden and the permanent downturn of capital stock growth in finland we are thus able to explain why the crisis of the early 1990s had a more acute impact in finland than in its twin economy sweden

inequality and crime this paper considers the relationship between inequality and crime using data from urban counties the behavior of property and violent crime are quite different inequality has no effect on property crime but a strong and robust impact on violent crime with an elasticity above 0 5 by contrast poverty and police activity have significant effects on property crime but little on violent crime property crime is well explained by the economic theory of crime while violent crime is better explained by strain and social disorganization theories

an intertemporal general equilibrium model of asset prices this paper develops a continuous time general equilibrium model of a simple but complete economy and uses it to examine the behavior of asset prices in this model asset prices and their stochastic properties are determined endogenously one principal result is a partial differential equation which asset prices must satisfy the solution of this equation gives the equilibrium price of any asset in terms of the underlying real variables in the economy in this paper we develop a general equilibrium asset pricing model for use in applied research an important feature of the model is its integration of real and financial markets among other things the model endogenously determines the stochastic process followed by the equilibrium price of any financial asset and shows how this process depends on the underlying real variables the model is fully consistent with rational expectations and maximizing behavior on the part of all agents our framework is general enough to include many of the fundamental forces affecting asset markets yet it is tractable enough to be specialized easily to produce specific testable results furthermore the model can be extended in a number of straightforward ways consequently it is well suited to a wide variety of applications for example in a companion paper cox ingersoll and ross 7 we use the model to develop a theory of the term structure of interest rates many studies have been concerned with various aspects of asset pricing under uncertainty the most relevant to our work are the important papers on intertemporal asset pricing by merton 19 and lucas 16 working in a continuous time framework merton derives a relationship among the equilibrium expected rates of return on assets he shows that when investment opportunities are changing randomly over time this relationship will include effects which have no analogue in a static one period model lucas considers an economy with homogeneous individuals and a single consumption good which is produced by a number of processes the random output of these processes is exogenously determined and perishable assets are defined as claims to all or a part of the output of a process and the equilibrium determines the asset prices our theory draws on some elements of both of these papers like merton we formulate our model in continuous time and make full use of the analytical tractability that this affords the economic structure of our model is somewhat similar to that of lucas however we include both endogenous production and

the role of shocks and institutions in the rise of european unemployment the aggregate evidence two key facts about european unemployment must be explained the rise in unemployment since the 1960s and the heterogeneity of individual country experiences while adverse shocks can potentially explain much of the rise in unemployment there is insufficient heterogeneity in these shocks to explain cross country differences alternatively while explanations focusing on labour market institutions explain current heterogeneity well many of these institutions pre date the rise in unemployment based on a panel of institutions and shocks for 20 oecd nations since 1960 we find that the interaction between shocks and institutions is crucial to explaining both stylised facts

colombia s income from the drug trade abstract we estimate the net dollar proceeds that colombia receives from the drug trade making use of production data recently compiled by us authorities care is taken in assuring that our estimations are consistent with previous research on cocaine consumption in the united states and production in bolivia and peru we show that net dollar proceeds which used to represent around 7 of gdp and 70 of exports in the early 1980s now represent around 3 of gdp and 25 of exports these numbers though significant pale in comparison with those suggested in the popular press according to which colombia s economy has been all but overtaken by the drug trade

the consumption based capital asset pricing model the paper provides conditions on the primitives of a continuous time economy under which there exist equilibria obeying the consumption based capital asset pricing model ccapm the paper also extends the equilibrium characterization of interest rates of cox ingersoll and ross 1985 to multi agent economies we do not use a markovian state assumption this work provides sufficient conditions on agents primitives for the validity of the consumption based capital asset pricing model ccapm of breeden 1979 as a necessary condition breeden showed that in a continuous time equilibrium satisfying certain regularity conditions one can characterize returns on securities as follows the expected instantaneous rate of return on any security in excess of the riskless interest rate the security s expected excess rate of return is a multiple common to all securities of the instantaneous covariance of this excess return with aggregate consumption increments this common multiple is the arrow pratt measure of risk aversion of a representative agent rubinstein 1976 published a discrete time precursor of this result the exis tence of equilibria satisfying breeden s regularity conditions had been an open issue we also show that the validity of the ccapm does not depend on breeden s assumption of markov state information and present a general asset pricing model extending the results of cox ingersoll and ross 1985 as well as the discrete time results of rubinstein 1976 and lucas 1978 to a multi agent environment since the ccapm was first proposed much effort has been directed at finding sufficient conditions on the model primitives the given assets the agents preferences the agents consumption endowments and in a production econ omy the feasible production sets conditions sufficient for the existence of continuous time equilibria were shown in duffie 1986 but the equilibria demonstrated were not shown to satisfy the additional regularity required for the ccapm in particular breeden assumed that all agents choose pointwise interior consumption rates in order to characterize asset prices via the first order conditions of the bellman equation interiority was also assumed by huang 1987 in demonstrating a representative agent characterization of equilibrium an approach exploited here the use of dynamic programming and the bellman equation aside from the difficulty it imposes in verifying the existence of interior 1 financial support from the national science foundation is gratefully acknowledged we thank

hysteresis in unemployment unemployment has risen sharply in a number of countries and it appears to be becoming more persistent the experience of the 1970s and 1980s showed that adverse unemployment shocks could have long lasting effects with very serious economic and social consequences a key mechanism producing these adverse consequences was hysteresis in unemployment whereby temporary rises in unemployment generated by supply and or demand shocks had permanent or at least very persistent effects clearly it is important to understand how hysteresis mechanisms might operate in order to avoid such adverse outcomes on the other hand experience during the subsequent two decades showed that under more favourable macroeconomic conditions it is possible to observe good hysteresis effects now is a very appropriate time to re visit the issue of hysteresis in unemployment in order to avoid the errors of the 1970s and 1980s and if possible to get hysteresis effects working in a positive direction copyright 2011 oxford university press

guns violence and the efficiency of illegal markets in economics the standard mechanism for allocating scarce resources is the market a smoothly functioning market however is built upon legally enforceable contracts and property rights in the absence of law it is likely that violence or the threat thereof rather than prices is the means by which resources will be allocated interactions among animals provide clear evidence for this claim dominance hierarchies based on fighting ability also sometimes known as pecking orders have been documented across a wide variety of species e g primates chickens and other birds reptiles lobsters and a broad range of resources including food nesting sites and access to mates warder c allee 1938 john alcock 1993 evidence suggests that violence also plays a critical role in human interactions when property rights are not legally enforceable e g drug dealing and extortion see e g peter reuter 1983 geoffrey canada 1995 in this paper we analyze the determinants of the efficiency with which illegal markets allocate scarce resources we develop a stylized model in which players compete for a fixed prize with the winner determined by fighting ability efficiency in this context is determined by the amount of resources spent on fighting two factors affecting efficiency emerge from the model lethality and predictability perhaps surprisingly the use of more lethal mechanisms for resolving disputes does not have a clear impact on the social costs of violence the intuition underlying this result is that as the costs of losing a fight rise the willingness to fight falls we show that holding other factors constant the resources spent on fighting are lowest when the cost of losing is either very low or very high e g nuclear deterrence but over a wide range of lethality levels the overall social costs of fighting are fairly stable in contrast the costs of violence are critically linked to the predictability of dispute outcomes i e the certainty with which potential combatants know who will be victorious ex ante when the outcome of a conflict is highly correlated with observable characteristics such as strength or size there is little need to actually fight thus unpredictability all else equal increases the expected payoff to fighting for the lower ranked member leading to more conflicts

unemployment persistence does the size of the shock matter one of the stylized facts of unemployment is that shifts in its mean rate between decades and half decades account for most of its variance in this paper we use a statistical analysis based on markov switching regression models to identify the dates of infrequent changes in the mean of the unemployment rate series of fifteen countries we find that in most countries unemployment persistence is much reduced once the infrequently changing mean rate induced by large shocks to unemployment has been removed we conclude that the observed persistence in unemployment appears to be consistent with multiple equilibria models and models with an endogeneous natural rate 1998 john wiley sons ltd

the monopoly of violence evidence from colombia many states in latin america africa and asia lack the monopoly of violence even though this was identified by max weber as the foundation of the state and thus the capacity to govern effectively in this paper we develop a new perspective on the establishment of the monopoly of violence we build a model to explain the incentive of central states to eliminate nonstate armed actors paramilitaries in a democracy the model is premised on the idea that paramilitaries may choose to and can influence elections since paramilitaries have preferences over policies this reduces the incentives of the politicians they favor to eliminate them we then investigate these ideas using data from colombia between 1991 and 2006 we first present regression and case study evidence supporting our postulate that paramilitary groups can have significant effects on elections for the legislature and the executive next we show that the evidence is also broadly consistent with the implication of the model that paramilitaries tend to persist to the extent that they deliver votes to candidates for the executive whose preferences are close to theirs and that this effect is larger in areas where the presidential candidate would have otherwise not done as well finally we use roll call votes to illustrate a possible quid pro quo between the executive and paramilitaries in colombia language en

the role of economic theory in modelling the long run this argues for a closer link between the modelling of the long run relations in applied economics and the intertemporal equilibrium notion from economic theory this abstract was borrowed from another version of this item

wage dynamics reconciling theory and evidence u s macroeconomic evidence shows a negative relation between the rate of change of wages and unemployment in contrast most theories of wage determination imply a negative relation between the level of wages and unemployment in this paper we ask whether one can reconcile the empirical evidence with theoretical wage relations we reach three main conclusions first we derive the condition under which the two can indeed be reconciled we show the constraints that such a condition imposes on the determinants of workers reservation wages as well as the relative importance of workers outside options as opposed to match specific productivity in wage determination second in the light of this condition we reinterpret the presence of an error correction term in macroeconomic wage relations for most european economies but not in the united states third we show that whether this condition holds or not has important implications for the effects of a number of variables from real interest rates to oil prices to payroll taxes on the natural rate of unemployment this abstract was borrowed from another version of this item

an intertemporal general equilibrium asset pricing model the case of diffusion information this paper provides sufficient conditions for the equilibrium price system and a vector of exogenously specified state variable processes to form a diffusion process in a pure exchange economy the conditions involve smoothness of agents utility functions and certain nice properties of the aggregate endowment process and the dividend processes of traded assets in place of the dynamic programming a martingale representation technique is utilized to characterize equilibrium portfolio policies this technique is useful even when there does not exist a finite dimensional markov structure in the economy and thus the markovian stochastic dynamic programming is not applicable a gents are shown to hold certain hedging mutual funds and the riskless asset in contrast to earlier results the market portfolio does not have a special role in hedging since the markets are dynamically complete when there exists a finite dimensional markov system in the economy the dimension of the hedging demand identified through the markovian dynamic programming may be much larger than that identified by the martingale method copyright 1987 by the econometric society

competition and investment in flexible technologies this paper examines the implications of market structure on investment in flexible manufacturing systems fms we analyze a two stage game in which firms choose between a flexible and a less flexible technology in the first stage then choose production quantities in the second stage in equilibrium a large proportion of fms firms is associated with more concentrated markets our model predicts that a larger market and or a more differentiated product results in a higher proportion of fms firms being sustained these predictions are empirically supported using cross section industry level data from both the us and japan

trafficking networks and the mexican drug war abstract drug trade related violence has escalated dramatically in mexico since 2007 and recent years have also witnessed large scale efforts to combat trafficking spearheaded by mexico s conservative pan party this study examines the direct and spillover effects of mexican policy toward the drug trade regression discontinuity estimates show that drug related violence increases substantially after close elections of pan mayors empirical evidence suggests that the violence reflects rival traffickers attempts to usurp territories after crackdowns have weakened incumbent criminals moreover the study uses a network model of trafficking routes to show that pan victories divert drug traffic increasing violence along alternative drug routes jel d72 d85 k42 o17 z13

capital formation and unemployment this paper criticizes the current enthusiasm for labour market policies as the main route to employment creation in oecd countries such policies are normally seen as a means of encouraging more employment on existing capital stock this approach is one sided and downplays the equally important task of increasing productive capacity with more investment in productive capacity conventional labour market policies for increasing employment would be more effective and some might be unnecessary the paper analyses the role of capital stock within the framework of a simple nairu model based on previous work by the author it also presents some empirical evidence copyright 1995 by oxford university press

deposit rate ceilings and the market value of banks the case of france 1971 1981 the objective of this paper is to develop an empirical methodology to assess the relationship between the market value and the asset liability structure of banks a simple bank valuation model is suggested and empirically tested on a sample of french banks the paper attempts to evaluate the effect of corporate taxation the rent on deposits subject to interest rate ceilings and the determinants of the 1974 drop in banks market values copyright 1992 by ohio state university press

equilibrium in capm without a riskless asset in the mean variance capm without a riskless asset the possibility of satiation sometimes leads to non existence of general equilibrium moreover because portfolio preferences are not necessarily monotone equilibrium asset prices when they exist may be negative or zero to demonstrate the possibility of non existence and to develop an intuitive understanding of when and why equilibrium does or does not exist this paper fully investigates the special case of utility functions linear in mean and variance and partially extends the results to the general case

positive prices in capm some equilibrium prices in capm may be negative because of nonmonotonicity of preferences we identify several sets of sufficient conditions for prices to be positive the central conditions impose bounds on the investors risk aversion these bounds do not need to hold globally but only in a relevant range of portfolios or combinations of mean and standard deviation the relevant range is specified on the basis of exogenous parameters and variables and it must contain any endogenously determined equilibrium the bounds on risk aversion ensure that the preferences for assets are sufficiently well behaved within the relevant range the two period mean variance capital asset pricing model capm has the peculiar property that preferences may not be monotone the expected return to an investor s portfolio increases as he holds more and more shares of the assets but so does the variance of return it may be that at some point the additional expected return gained from adding more shares to the portfolio is not sufficient to compensate for the increase in variance if so then the induced preferences for assets are not monotone nonmonotonicity of preferences in the mean variance model is analyzed in nielsen 1987 because portfolio preferences are not necessarily monotone equilibrium asset prices may be negative or zero in fact it is possible that the value of the market portfolio of risky assets is negative this is demonstrated in nielsen 1985 1990a and in two examples in the present paper when the capm is used as a model of the prices of stocks which in reality have limited liability it is of course disturbing that it may predict negative prices it can be seen as a symptom of the fact that mean variance preferences are not always a good approximation to reality this paper analyzes various conditions on the exogenous parameters which ensure that the preferences are sufficiently realistic to yield positive prices the exogenous parameters in question are the expectations variances and covariances of total returns the initial allocations of the assets endowments and the investors utility functions for mean and variance of return the analysis applies to the classical version of the capm with a riskless asset as developed by sharpe 1964 lintner 1965 and mossin 1966 as well as the capm with risky assets only which was introduced by black 1972 and has been much used in empirical work under the name the zero beta or two factor capm

capital accumulation and unemployment a tale of two continents in contrast to much recent work regarding the causes of european unemployment in this paper we emphasize the importance of capital accumulation but unlike the few previous studies which have examined the relationship between capital accumulation and unemployment we argue that what matters for the evolution of employment and the unemployment rate is not the absolute growth rate of a country s capital stock but its evolution relative to other countries capital stock the empirical validity of the above statement is demonstrated for almost all oecd countries using quarterly time series data for the period 1961 1995 more detailed evidence is also presented for germany japan and the united kingdom

diamonds are forever wars are not is conflict bad for private firms this paper studies the relationship between civil war and the value of firms in a poor resource abundant country using microeconomic data for angola we focus on diamond mining firms and conduct an event study on the sudden end of the conflict marked by the death of the rebel movement leader in 2002 we find that the stock market perceived this event as bad news rather than good news for companies holding concessions in angola as their abnormal returns declined by 4 percentage points the event had no effect on a control portfolio of otherwise similar diamond mining companies this finding is corroborated by other events and by the adoption of alternative methodologies we interpret our findings in light of conflict generated entry barriers government bargaining power and transparency in the licensing process jel d74 g32 o13 o17 q34

the economic crisis of the 1990s in finland finland s depression a tale of bad luck and bad policies in the 1990s finland underwent a deep depression as its gdp dropped about 14 and unemployment rose from 3 to almost 20 this is a story of bad luck and bad policies bad luck took the form of external shocks the collapse of trade with the former soviet union in 1991 but also sharp cycles in the oecd area however bad luck is far from being the whole story in the absence of bad policies finland would have experienced a recession not a depression bad policies included a poorly designed financial regulation and mistaken reactions to the onset of the crisis of particular interest is the role of financial factors in triggering the crisis and aggravating the effects of bad policies not only were consumption and investment spending hurt by the credit crunch but there is evidence that the private sector s indebtedness has increased structural unemployment which explains why the recovery is proceeding with few job creations a number of general lessons emerge they concern the deregulation of financial markets the policy reaction to massive capital inflows and the role of employment policies seppo honkapohja and erkki koskela

phillips curves and unemployment dynamics a critique and a holistic perspective the conventional wisdom that inflation and unemployment are unrelated in the long run implies that these phenomena can be analysed by separate branches of economics the macro literature tries to explain inflation dynamics and estimates the nairu the labour macro literature tries to explain unemployment dynamics and determine the real economic factors that drive the natural rate of unemployment we show that the orthodox view that the new keynesian phillips curve is vertical in the long run and that it cannot generate substantial inflation persistence relies on the implausible assumption of a zero interest rate in the light of these results we argue that a holistic framework is needed to jointly explain the evolution of inflation and unemployment

eec integration towards 1992 some distributional aspects gains and losses from 1992 damien j neven this paper examines how the benefits and costs of the internal market programme will be shared across member states the main conclusion is that the northern european countries stand to gain little from 1992 the only exception is the uk which will benefit from integration because initially it is less integrated than its northern neighbours the main beneficiaries will be the southern european countries they will benefit both from a better exploitation of their comparative advantage in labour intensive commodities and from the gains from unexploited scale economies which have already been substantially exploited in northern europe although northern countries have a comparative advantage in goods which are intensive in human capital southern markets for these goods are relatively small that is why it is the southern countries which stand to gain most even if in addition ec trade with the rest of the world is liberalized at the same pace as within the ec labour intensive production especially clothing and footwear in the south could increase by as much as 14 after 1992 areas in the north where such industries are concentrated may be the largest losers from 1992

capital accumulation labour market institutions and unemployment in the medium run according to the mainstream view labour market institutions lmis are the key determinants of unemployment in the medium run the actual empirical explanatory power of measures for labour market institutions however has recently been called into question the keynesian view holds periods of high real interest rates and insufficient capital accumulation responsible for unemployment empirical work in this tradition has paid little attention to the role of lmis this paper contributes to the debate by highlighting the role of autonomous changes in capital accumulation as a macroeconomic shock in the empirical analysis medium term unemployment is explained by capital accumulation lmis and a number of macroeconomic shocks in a panel analysis covering 20 oecd countries the economic effects of changes in lmi variations in capital accumulation and other macro shocks are compared capital accumulation and the real interest rate are found to have statistically significant effects that are robust to the inclusion of control variables and show larger effects than lmi

strategic choice of flexible production technologies and welfare implications this paper examines the market conditions under which firms would choose a more flexible production technology with respect to product design the authors use a two stage game in which firms choose between flexible and less flexible production technologies in the first stage and subsequently choose output they find that consumers would benefit from the introductions of flexible production technologies in their model the authors also find that the production technology game is a prisoner s dilemma when firms invest in flexible manufacturing systems they derive the conditions under which the resulting equilibria are efficient copyright 1990 by blackwell publishing ltd

market microstructure effects of government intervention in the foreign exchange market as asymmetric information model of the bid ask spread is developed for a foreign exchange market subject to occasional government interventions traditional tests of the unbiasedness of the forward rate as a predictor of the future spot rate are shown to be inconsistent when the rates are measured as the average of their respective bid and ask quotes larger bid ask spreads on fridays are documented reliable evidence of asymmetric bid ask spreads for all days of the week albeit more pronounced on fridays are presented the null hypothesis that the forward rate is an unbiased predictor of the future spot rate continues to be rejected the regression slope coefficients increase toward unity however indicating a less variable risk premium

existence of equilibrium in capm abstract in the mean variance capital asset pricing model capm non monotonicity of preferences may lead to satiation and short selling as well as satiation may lead to non existence of equilibrium this paper identifies several sets of sufficient conditions for equilibrium to exist the nature of the central conditions is to impose bounds on the investors degree of risk aversion as measured by the marginal rate of substitution between mean and standard deviation of return these bounds do not need to hold globally but only in a relevant range of portfolios or combinations of mean and standard deviation

portfolio selection in the mean variance model a note a little recognized feature of the mean variance portfolio selection model is that induced preferences for asset holdings are not necessarily monotone more of an asset or portfolio is not necessarily better even if the asset or portfolio has positive expected return the model predicts that an investor typically wants only a limited number of shares of an asset and beyond that the increase in mean return from costlessly getting more of an asset is not sufficient to compensate for the increased risk this is reasonable if the model describes a market for contracts with unlimited liability where total returns may be negative e g they may be normally distributed it is unreasonable however if the model is used to describe a stock market with limited liability in that case it is desirable to impose conditions that ensure that there is no upper limit to how much of an asset or portfolio the investor wants the sharpest possible conditions are identified in section i since portfolio preferences are not monotone global satiation is possible again this is unrealistic when liability is limited satiation is bothersome also because it may lead to nonexistence of equilibrium in black s 4 capm without a riskless asset as demonstrated in nielsen 9 uniqueness of equilibrium in capm is investigated in nielsen 10 section i identifies the exact conditions under which global satiation does or does not occur the conditions compare the maximum ratio of mean to standard deviation of total return available from the assets with the investor s limiting degree of risk aversion as measured by the slope of his or her indifference curves at high levels of risk an optimal portfolio may or may not exist in the portfolio selection problem depending on the asymptotic slopes of the efficient frontier and the investor s indifference curves section ii identifies the exact conditions mean variance behavior can arise from expected utility maximization based on normal distributions in that case the conditions for nonsatiation and for existence of optimal portfolios can be stated in terms of the von neumannmorgenstern utility function section iii relates the relevant properties of the utility function for standard deviation and mean to properties of the von neumann morgenstern utility function