vintage technologies and skill constraints evidence from u s exports of new and used machines when countries import production machinery they must choose between new and used equipment this article looks at that choice in the presence of labor saving technical progress and complementarity between technologies and skills within the firm it develops a theoretical model of the market for used machines it then analyzes data on united states u s exports of metalworking machine tools by country of destination classifying machines according to their vintage and their technological characteristics the data show that the share of used equipment imported is higher if the importing country has a lower level of development as measured by income per capita econometric estimation of the determinants of this share shows that it also is higher the greater is the technological change embodied in the machine or the greater is the change in the skills required to run the machine efficiently these results indicate that technological factors and skill constraints may be as important as factor prices in determining the choice of technique in developing countries the policy recommendation emerging from this work avoid constraints on imports of used equipment is similar to that in the existing literature but the reasoning is different instead of emphasizing inappropriate capital labor ratios for low wage countries the results indicate that investment in advanced technologies is effective only if importing countries have the skills to use them

economic development and the family structure from the pater familias to the nuclear family we provide a theory that is able to account for the observed comovement between the shift in intergenerational living arrangements from coresidence to non coresidence and economic development our theory is consistent with the diminution in the status of the elderly documented by some sociologists the results from our analysis show that when technical progress is fast enough the economy experiences a shift from stagnation to growth there is a transition from coresidence to non coresidence and the social status of the elderly tends to deteriorate

measuring organizational downside risk despite widespread incorporation of risk measures in strategy research there is little consensus regarding the meaning and measurement of risk in contrast to the variability measures widely used in strategy studies this paper draws from behavioral decision theory finance and management theory to present an alternative perspective on organizational risk downside risk the paper explains three categories of organizational downside risk measures based on the concept of lower partial moments the latter sections of the paper present considerations involved in specifying operational measures of downside risk and an empirical comparison of alternative downside risk measures

managerial skills acquisition and the theory of economic development micro level studies suggest managerial skills play a key role in the adoption of modern technologies in this paper we model the interactive process between on the job managerial skill acquisition and the adoption of modern technology we use the model to illustrate why some countries develop managerial skills quickly and adopt best practice technologies while others stay backwards the model also explains why managers will not migrate from rich countries to poor countries as would be needed to generate convergence finally we show why standard growth accounting exercises will incorrectly attribute a large proportion of managerial skills contribution to tfp and we quantify the importance of this bias aq2

export diversification through resource based industrialization the case of natural gas for small resource rich developing economies specialization in raw exports is usually considered to be detrimental to growth and resource based industrialization rbi is often advocated to promote export diversification this paper develops a new methodology to assess the performance of these rbi policies we first formulate an adapted mean variance portfolio model that explicitly takes into consideration i a technology based representation of the set of feasible export combinations and ii the cost structure of the resource processing industries second we provide a computationally tractable reformulation of the resulting mixed integer nonlinear optimization problem finally we present an application to the case of natural gas comparing current and efficient export oriented industrialization strategies of nine gas rich developing countries

the rationale of the mean standard deviation analysis skewness preference and the demand for money publisher summary this chapter discusses the rationale of the mean standard deviation analysis skewness preference and the demand for money in january 1969 issue of the review of economic studies karl borch and martin feldstein separately criticized the widely used mean variance analysis of portfolio selection borch contended that any system of upward sloping mean standard deviation e s indifference curves can be shown to be inconsistent with the basic axiom of choice under uncertainty he pointed out that one can always pick any two points on an upward sloping indifference curve to represent two bernoulli distributions with probability 1 p of gaining the same amount x in both the cases and probability p of gaining y1 in the case of one distribution and y2 in the case of the second distribution with y2 y1 if the second distribution represents the point to the northeast of the other point then by the dominance axiom the second distribution must be preferred to the first which contradicts the basic meaning of indifference curves feldstein by using a log utility function and a lognormal distribution for investment outcome showed that e s indifference curves for a risk averter need not be convex downwards though upward sloping they would change from convex to concave once the standard deviation of the outcome exceeds the mean multiplied by on the face of it this seems to suggest that risk aversion might decrease as risk is increased beyond a certain extent

disruption costs learning by doing and technology adoption abstract we study technology adoption in a dynamic model of price competition adoption involves disruption costs and learning by doing because of disruption costs the adopting firm begins in a market disadvantage which may persist if its rival captures the customers that the adopting firm needs to learn the technology the prospect of future rents by the rival results in i a failure to adopt socially efficient technologies ii an equilibrium preference for technologies that are learned faster but have lower social value and iii more technologies being adopted if more firms enter the market

assessing energy price induced improvements in efficiency of capital in oecd manufacturing industries to assess how capital stocks adapt to energy price changes it is necessary to account for the impacts on different vintages of capital and to account separately for price induced and autonomous improvements in the energy efficiency of capital stock the results of econometric analysis for five manufacturing industries in 19 oecd countries between 1990 and 2005 indicate that higher energy prices resulted in smaller energy use due to both improved energy efficiency of capital stock and reduced demand for the energy input the investment response to energy prices varied considerably across manufacturing industries being more significant in energy intensive sectors the results of policy simulations indicate that a carbon tax can deliver significant reductions in energy consumption in the medium run with modest declines in energy using capital stock

on equilibrium for overlapping generations organizations a necessary feature for equilibrium is that beliefs about the behavior of other agents are rational and indi viduals maximize we argue that in stationary olg environments this implies that any future generation in the same situation as the initial generation must do as well as the initial generation did in that situation we conclude that the existing equilibrium concepts in the literature do not satisfy this condition we then propose an alternative equilibrium concept organizational equilibrium that satisfies this condition we show that equilibrium exists it is unique and it improves over autarky without achieving optimality moreover the equilibrium can be readily found by solving a maximization program rios rull thanks the national science foundation for grant sbr 9309514 and the university of pennsylvania re search foundation for their support prescott thanks the national science foundation for grant sbr 9996201 we thank julio davila igor livshits larry jones dan silverman and attendants at seminars in the penn macro lunch group federal reserve bank of minneapolis cornell penn state university macro theory conference the univer sity of rochester ucla and the 1999 midwest theory meetings for comments the views expressed herein are those of the authors and not necessarily those of the federal reserve bank of minneapolis or the federal reserve system

path dependence endogenous innovation and growth the article presents a model of endogenous innovation and growth in which technological change is path dependent the historical pattern of technological development plays a central role in determining the pace of future technological change path dependence is explained using a distinction between fundamental and secondary knowledge the economy moves endogenously between periods of drastic and nondrastic innovation technological lock in is shown to be a special case of path dependence the model provides a rationale for cycles in technological leadership this rationale exists in equilibria with positive levels of fundamental research and in a world with no imitation

optimal production allocation and distribution supply chain networks abstract enterprise optimisation can rapidly strip significant bottom line costs out of global operations giving companies a real competitive edge the benefits of managing supply chain networks by integrating operational design and financial decisions have been acknowledged by the industrial and academic community the objective of this work is to determine the optimal configuration of a production and distribution network subject to operational and financial constraints operational constraints include quality production and supply restrictions and are related to the allocation of the production and the work load balance financial constraints include production costs transportation costs and duties for the material flowing within the network subject to exchange rates as a business decision the out sourcing of production is considered whenever the organisation cannot satisfy the demand a mixed integer linear programming milp model is proposed to describe the optimisation problem a case study for the coatings business unit of a global specialty chemicals manufacturer is used to demonstrate the applicability of the approach in a number of scenarios

vintage human capital and learning curves abstract i study a vintage human capital model in which long lived workers accumulate human capital following an exogenous learning curve different skill levels inside a vintage are complementary in production this makes the ex ante homogeneous workers enter different vintages the continuous time framework allows me to study the timing decision for the technology phase out differentially and to derive sharp characterization for wages and the distribution of workers in the dying technology i show how to posit and solve a planner s problem and construct equilibrium in this way consistent with empirical evidence i show that the experience premium is always positive but diminishes as a technology ages the connection between workers learning curves and the technology s progress curve is characterized

redesign of global supply chains with integration of transfer pricing mathematical modeling and managerial insights abstract unlike the supply chain sc design problem which deals with the configuration of a new sc the redesign problem assumes that a sc already exists and focuses on its reconfiguration in order to take profit of the changing logistics financial and fiscal advantages offered by each country first this requires considering specific decisions and cost factors such as those associated with facility closing and capacity relocation these aspects are often ignored by sc design models second to better capitalize on the tax advantages in each country the redesign of sc requires the consideration of taxation rates and mainly transfer pricing indeed companies can use transfer pricing to shift profits to lower tax countries which may impact on the sc redesign decisions e g on the relocation of operations and manufacturing facilities this paper contributes to the literature by 1 developing a large scale optimization model that is specific to the problem of sc redesign while addressing decisions costs and complexity factors that are often ignored by the model based sc design literature 2 integrating transfer pricing in the model by using two methods one of them is the profit split method that is dictated by the oecd transfer pricing guidelines 1995 2010 which could be considered as a novelty in large scale sc optimization models and 3 using the model to derive a series of insights that may be helpful for companies and governments most of these insights are difficult to obtain without the support of models like the one developed here

technology diffusion and international income convergence abstract a macroeconomic model of international income convergence driven by differences in technology is presented ldc firms adopt foreign technology by paying an upfront cost of adaptation and early adopters create a positive externality for followers in equilibrium adoption is gradual and so is income convergence because of the externality small differences in adoption costs across ldcs can lead to large differences in long run income during convergence the ldc economy is dualistic with large high technology firms operating alongside small traditional establishments the effects of trade policy and direct foreign investment are also examined

shortfall as a risk measure properties optimization and applications motivated from second order stochastic dominance we introduce a risk measure that we call shortfall we examine shortfall s properties and discuss its relation to such commonly used risk measures as standard deviation var lower partial moments and coherent risk measures we show that the mean shortfall optimization problem unlike mean var can be solved e7ciently as a convex optimization problem while the sample mean shortfall portfolio optimization problem can be solved very e7ciently as a linear optimization problem we provide empirical evidence a in asset allocation and b in a problem of tracking an index using only a limited number of assets that the mean shortfall approach might have advantages over mean variance 2003 elsevier b v all rights reserved

vintage human capital growth and the diffusion of new technology we develop a model of vintage human capital in which each technology requires vintage specific skills we examine the properties of a stationary equilibrium for our economy the stationary equilibrium is characterized by an endogenous distribution of skilled workers across vintages the distribution is shown to be single peaked under general conditions there is a lag between the appearance of a technology and its peak usage a phenomenon known as diffusion an increase in the rate of exogenous technological change shifts the distribution of human capital to more recent vintages thereby increasing the diffusion rate

innovation adoption and diffusion when there are competing innovations abstract firms face a choice between two innovations without knowing which of the two is better each firm has a prior that one of the innovations is better which is updated by bayes rule as trials with the innovations are made a simple decision rule indicating which innovation should be tried given any posterior is derived and used to define an expected diffusion curve for the better innovation this curve has the commonly observed ogive shape even in the absence of any external demonstration effect when the distribution of firm priors belongs to a general class

the 2005 lawrence r klein lecture emergent class structure this article presents a model of the emergent class structure in which a society inhabited by inherently identical households may be endogenously split into the rich bourgeoisie and the poor proletariat for some parameter values the model has no steady state where all households remain equally wealthy in this case the model predicts emergent class structure or the rise of class societies even if every household starts with the same amount of wealth the society will experience symmetry breaking and will be polarized into two classes in steady state where the rich maintain a high level of wealth partly due to the presence of the poor who have no choice but to work for the rich at a wage rate strictly lower than the fair value of labor the nonexistence of the equal steady state means that a one shot redistribution of wealth would not be effective as wealth inequality and the class structure would always reemerge thus the class structure is an inevitable feature of capitalism for other parameter values on the other hand the model has the unique steady state which is characterized by perfect equality in this case the model predicts dissipating class structure or the fall of class societies even if the society starts with significant wealth inequality labor demand by the rich employers pushes up the wage rate so much that workers will escape from the poverty and eventually catch up with the rich eliminating wealth inequality and the class structure in the long run in an extension we introduce self employment which not only provides the poor with an alternative to working for the rich but also provides the rich with an alternative to investment that creates jobs due to this dual nature of self employment the effects of self employment turn out to be quite subtle yet within the present framework it is possible to offer a complete characterization of the steady states even in the presence of self employment

a strategic tactical model for the supply chain design in the delocalization context mathematical formulation and a case study abstract in this paper we propose a mathematical model for the design of supply chains in the delocalization context our main objective is to develop a strategic tactical supply chain design model that integrates all the relevant components that characterize the delocalization problem we adopt the activity based approach to model the problem and we focus on the logistic decisions of activity location technology choice supplier selection etc and the financial decisions of transfer pricing transportation costs allocation etc the mathematical formulation is illustrated by a case study from the automotive sector a comparison between the model solution and the real decisions is used to prove the applicability and the utility of the proposed model

a simple approximation for semivariance abstract semivariance can differentiate among skewed return distributions but variance is unable to do so thus semivariance has been used as a risk surrogate in portfolio analysis and capital budgeting problems unfortunately semivariance analysis is relatively unknown and poses difficult analytic and computational problems in this paper an expression is derived which very closely approximates semivariance this expression is simple in form and uses only familiar statistics namely mean variance critical value and cumulative probability below the critical value

the enduring impact of the american dust bowl short and long run adjustments to environmental catastrophe the 1930 s american dust bowl was an environmental catastrophe that greatly eroded sections of the plains analyzing new data collected to identify low medium and high erosion counties the dust bowl is estimated to have immediately substantially and persistently reduced agricultural land values and revenues during the depression and through at least the 1950 s there was limited reallocation of farmland from activities that became relatively less productive agricultural adjustments such as reallocating land from crops to livestock recovered only 14 to 28 of the initial agricultural cost the economy adjusted predominately through migration rather than through capital inows and increased industry

formation of a strategic manufacturing and distribution network with transfer prices abstract we propose a profit maximization model for the decision support system of a firm that wishes to establish or rationalize a multinational manufacturing and distribution network to produce and deliver finished goods from sources to consumers the model simultaneously evaluates all traditional location factors in a manufacturing and distribution network design problem and sets intra firm transfer prices that take account of tax and exchange rate differentials between countries utilizing the generalized benders decomposition approach we exploit the partition between the product flow and the cash allocation i e the pricing and revenue assignment decisions in the supply chain to find near optimal model solutions our proposed profit maximizing strategic planning model produces intuitive results we offer computational experiments to illustrate the potential valuable guidance the model can provide to a firm s supply chain design strategic planning process

asset pricing in a generalized mean lower partial moment framework theory and evidence a new asset pricing model that generalizes earlier results in the downside risk literature is developed and empirically tested using a multivariate approach by specifying risk as deviations below any arbitrary target rate of return the generalized mean lower partial moment mlpm model overcomes the limited appeal of earlier formulations and moreover a large class of extant pricing models using alternative risk measures variance semivariance semideviation probability of loss etc becomes special cases of the new framework empirical tests indicate that the new model cannot be rejected against an unspecified alternative for a large set of target rates of return the traditional capm on the other hand is rejected as a well specified alternative the mlpm target rates inferred from market data appear to be related to equity market mean returns rather than to the riskfree rate the target rate that is implicit in the capm and explicit in earlier downside risk formulations the attractiveness of downside risk measures for decision making purposes has been noted in the financial economic literature for over a quarter of a century 1 risk from this perspective is measured in terms of deviations below some exogenously prespecified target rate of return and a formal analysis of these risk measures for various utility functions has been presented by bawa 1975 in terms of the lower partial moment lpm of the asset distributions the appeal of these risk measures has been based in part on their consistency with the way individuals actually perceive risk notwithstanding its intuitive appeal this area of research has been virtually neglected in recent years we believe that this disaffection with downside risk models tends from two sources first earlier models of this genre exogenously specify the target rate to equal the risk free interest rate in the absence of a satisfactory theory for explaining how investors establish their target rates this assumption as argued herein has been motivated more by technical reasons than economic considerations second empirical tests

investment options and the business cycle abstract this paper extends r mehra e c prescott recursive competitive equilibrium the case of homogeneous households econometrica 48 1980 1365 1380 to a production economy with two capital goods it is an rbc model in which each unit of investment requires a new idea an option when options are scarce new capital is harder to put in place and the value of old capital rises thus the stock market and tobin s q are negative indexes of intangibles during a boom q rises gradually as options are used up because investment represents an exercise of options it has an intertemporal substitution tradeoff that is absent from the adjustment cost model equilibrium may be efficient even without markets for knowledge the stock market may suffice

two moment decision models and expected utility maximization two moment decision models are consistent with expected utility maximization only if the choice set or the agent s preferences are restricted this paper identifies a restriction which is sufficient to ensure this consistency and confirms that it holds in many economic models the implications for economic analysis are then derived two different approaches to representing an agent s preferences over strategies yielding random payoffs are in wide use under the mean standard deviation ms approach the agent is assumed to rank the alternatives according to the value of some function defined over the first two moments of the random payoff while the expected utility eu criterion assumes that the expected value of some utility function defined over payoffs is used instead the fact that there are these two competing approaches has generated a considerable literature some authors are concerned with the advantages and disadvantages of each while others deal with conditions under which the potentially different approaches would yield the same results or at least approximately so space does not

models of political economy of growth a short survey abstract this paper surveys recent work on the political economy of growth after presenting the general structure of a model of politics and growth with heterogenous agents we discuss the role of dynamic strategic political behavior the existence of multiple equilibria and how endogenous political participation interacts with the dynamics of wealth distribution and economic development

comparative statics under uncertainty the case of mean variance preferences we analyze the comparative statics of optimal decisions under uncertainty when preferences are represented by twomoment mean variance utility functions we relate our findings to concepts for risk attitudes that are familiar from the expected utility approach in the two parameter approach a number of plausible comparative static effects already emerges under the assumption of decreasing absolute risk aversion to determine comparative static effects of changes in background risks stronger concepts are needed risk vulnerability temperance and standardness imply appropriately transferred to the mean variance framework the plausible effect that risk taking will be reduced if background risks increase 2002 elsevier b v all rights reserved

experience vs obsolescence a vintage human capital model abstract i introduce endogenous human capital accumulation into an infinite horizon version of chari and hopenhayn s 1991 4 vintage human capital model returns to skill and tenure premia are highest in young vintages where skill is scarcest and agents accumulate human capital fastest as the vintage ages the skill premium decreases and vanishes entirely upon vintage death workers run through cycles of human capital accumulation their wages rise as they accumulate skill undergo downward pressure as the technology ages and finally drop sharply when the worker switches to a new technology the results are in line with german linked employer employee data tenure premia are highest in young establishments as well as in fast growing industries occupations and establishments a calibration exercise suggests that human capital accumulation is the most important determinant of workers wage profiles whereas changes to the price of skill and vintage productivity gains play a smaller quantitative role

integration of financial statement analysis in the optimal design of supply chain networks under demand uncertainty abstract models that aim to optimize the design of supply chain networks have become a mainstream in the supply chain literature this paper aims to fill a gap in the literature by introducing a mathematical model that integrates financial considerations with supply chain design decisions under demand uncertainty the proposed mixed integer linear programming milp problem enchases financial statement analysis through financial ratios and demand uncertainty through scenario analysis the applicability of the model is illustrated by using a case study along with a sensitivity analysis on financial parameters expressing the business environment the model could be used as an effective and convenient strategic decision tool by supply chain managers

the benefits of differential variance based constraints in portfolio optimization abstract the main problem of portfolio optimization is parameter estimation error various methods have been suggested to mitigate this problem among which are shrinkage resampling bayesian updating naive diversification and imposing constraints on the portfolio weights this study suggests two substantial extensions of the constrained optimization approach the variance based constraints vbc and the global variance based constraints gvbc methods by the vbc method the constraint imposed on the weight of a given stock is inversely proportional to its standard deviation the higher a stock s sample standard deviation the higher the potential estimation error of its parameters and therefore the tighter the constraint imposed on its weight gvbc employs a similar idea but instead of imposing a sharp boundary constraint on each stock a quadratic cost is assigned to deviations from the naive 1 n weight and a single global constraint is imposed on the total cost of all deviations comparing ten optimization methods we find that the two new suggested methods typically yield the best performance as measured by the sharpe ratio gvbc ranks first these results are obtained for two different datasets and are also robust to the number of assets under consideration

markets externalities and the dynamic gains of openness inflows of foreign knowledge can be the key for developing countries to catch up with the world technology frontier in this paper i construct a simple tractable model to analyze a the incentives of foreign firms to bring their know how to a developing country and b the incentives of domestic firms to invest in their own know how the model embeds the two mechanisms typically considered separately in the literature for the diffusion of knowledge externalities and markets the relative preponderance of these mechanisms significantly changes the dynamic implications of openness notably openness allows developing countries to fully catch up only when market transactions fully dominate the diffusion of ideas while externalities can also push domestic firms to upgrade their productivity the equilibrium exposure to ideas in the country is always below the frontier and asymptotically the country would remain importing foreign know how however in general the dynamic gains of openness are substantial

endowment structures industrial dynamics and economic growth this paper develops a dynamic general equilibrium model to explore industrial evolution and economic growth in a closed developing economy the authors show that industries will endogenously upgrade toward the more capital intensive ones as the capital endowment becomes more abundant the model features a continuous inverse v shaped pattern of industrial evolution driven by capital accumulation as the capital endowment reaches a certain threshold a new industry appears prospers then declines and finally disappears while the industry is declining a more capital intensive industry appears and booms ad infinitum explicit solutions are obtained to fully characterize the whole dynamics of perpetual structural change and economic growth implications for industrial policies are discussed

vested interests and technology adoption this paper incorporates asymmetric interest group formation into a political economy model of barriers to technology adoption with many small industries coalitions of workers skilled in incumbent technologies lobby government for a prohibition on the adoption of superior technologies the model naturally generates concentrated benefits to vested interests and diused costs of barriers to technology adoption for reasonable parameter values this smallness of industry lobbies leads to barriers to the adoption of technologies that would make all workers more productive higher government corruption can lead to lower levels of tfp and per capita output the

a multi objective stochastic programming approach for supply chain design considering risk abstract in this paper we develop a multi objective stochastic programming approach for supply chain design under uncertainty demands supplies processing transportation shortage and capacity expansion costs are all considered as the uncertain parameters to develop a robust model two additional objective functions are added into the traditional comprehensive supply chain design problem so our multi objective model includes i the minimization of the sum of current investment costs and the expected future processing transportation shortage and capacity expansion costs ii the minimization of the variance of the total cost and iii the minimization of the financial risk or the probability of not meeting a certain budget the ideas of unreliable suppliers and capacity expansion after the realization of uncertain parameters are also incorporated into the model finally we use the goal attainment technique to obtain the pareto optimal solutions that can be used for decision making

var seductive but dangerous value at risk var has gained rapid acceptance as a valuable approach to risk management not all vars are equal however a study of var techniques used by dealers and end users reveals that var calculations differ significantly for the same portfolio vars are extremely dependent on parameters data assumptions and methodology calculation of eight common vars for three hypothetical portfolios demonstrates the potentially seductive but dangerous nature of any single approach to risk management in sum although var and other quantitative techniques are necessary aspects of an effective risk management program they are not sufficient to control risk

a holistic framework for short term supply chain management integrating production and corporate financial planning abstract traditional approaches for scm usually focus on process operations and neglect the financial side of the problem in this work we present a novel approach for holistically optimizing the combined effects of operations and finances in scm to achieve such integration between different business areas it is derived an integrated model for scm which incorporates process operations as well as budgetary constraints the novelty of this formulation lies not only in the insertion of financial aspects within a sc planning formulation but also in the choice of a financial performance indicator i e the change in equity as the objective to be optimized in the integrated model the main advantages of this mathematical formulation are highlighted through a case study in which the results obtained by the integrated model are compared with those computed by the traditional sequential strategy in which the operations are firstly computed and the finances are fitted afterwards the obtained results show the importance of devising broader modeling systems for scm leading to increased overall earnings and providing further insights on the interactions between operations and finances

investment and technical progress models in which the growth rate is exogenous provide no role for government in determining growth in our model growth is associated with investment through externalities from learning by watching rather than with the level of the capital stock presumption of a technical progress function with first increasing and then decreasing returns leads to multiple steady state growth equilibria there is also an explicit role of government policy in setting tax rates on output it follows that two economies with identical structures and stochastic tax policies may exhibit very different growth paths over sustained periods although the stationary distribution of growth rates is the same given the desirability in principle of subsidizing investment various practical methods are considered copyright 1992 by oxford university press

downside loss aversion and portfolio management downside loss averse preferences have seen a resurgence in the portfolio management literature this is due to the increasing use of derivatives in managing equity portfolios and the increased use of quantitative techniques for bond portfolio management we employ the lower partial moment as a risk measure for downside loss aversion and compare mean variance m v and mean lower partial moment m lpm optimal portfolios under nonnormal asset return distributions when asset returns are nearly normally distributed there is little difference between the optimal m v and m lpm portfolios when asset returns are nonnormal with large left tails we document significant differences in m v and m lpm optimal portfolios this observation is consistent with industry usage of m v theory for equity portfolios but not for fixed income portfolios

capital accumulation under technological progress and learning a vintage capital approach abstract in standard capital accumulation models all capital goods are equally productive and produce goods of the same quality however due to technological progress in reality it holds most of the time that newer capital goods are either more productive process innovation or produce goods of better quality product innovation implications of process innovation for the firm s investment policies are investigated while the output price development is subject to a business cycle and a given generation of capital goods gets more productive over time due to learning the problem is turned into an optimal control model that distinguishes the vintages of capital goods and where unlike most of the recent contributions it is possible to keep on investing in older technologies it is shown that i learning is one of the reasons why a firm may invest in old technologies even when apparently superior technologies are available ii investments in machines of a given age increase more over time under faster technological progress iii under faster technological progress investments are more vulnerable to output price developments and iv on average machines are older during recessions in deciding whether to invest in newer or older capital goods also the lower productivity due to aging versus differences in cost of discounting and acquisition have to be taken into account

replacement echoes in the vintage capital growth model this paper is concerned with a non standard source of fluctuations called echo effects i e the ability of an economy to reproduce its own past history in the 1960s growth theorists believed that this property could arise in vintage capital models taking the form of replacement echoes this line of research was stopped after the publication of solow et al 15 who showed that echoes should vanish in a solow growth model with vintage capital however the fundamental reason for this result has nothing to do with vintages rather it comes directly from the main assumption in a solow growth model i e at equilibrium investment is a constant fraction of output and does not depend on any optimal replacement rule we claim that in a more general ramsey model replacement echoes do not necessarily vanish and we show this in the case when instantaneous utility is linear c 1997 academic press

a microcredit contract model with a black scholes model under default risk microfinance has emerged as a new promise for alleviating poverty and improving the limited access to financial services by offering small loans with no pledged collateral requirement to the poor due to the unique features of microfinance the credit relationship between the lender and the borrower is considered to be the foundation of the business based on the concept of supply chain microfinance this paper develops scenario based stochastic microcredit contract models for a group case in order to obtain a minimum interest rate a black scholes debt model estimates volatility directly from market observable returns on a borrower s equity next incorporating the minimum interest rate the stochastic microcredit models are developed to calculate a proper interest rate while maintaining the financial sustainability of a corporation the stochastic microcredit models also include financial statement analysis through financial ratios to reflect the microfinance business environment through the comparison of the effect of cash flow bullwhip this study illustrates that the proposed model has the potential to decrease the bullwhip effect by determining a proper interest rate in microcredit the proposed models could be used by microfinance institutions as an effective credit risk tool

optimal mean variance portfolio selection using cauchy schwarz maximization fund managers highly prioritize selecting portfolios with a high sharpe ratio traditionally this task can be achieved by revising the objective function of the markowitz mean variance portfolio model and then resolving quadratic programming problems to obtain the maximum sharpe ratio portfolio this study presents a closed form solution for the optimal sharpe ratio portfolio by applying cauchy schwarz maximization and the concept of kuhn tucker conditions an empirical example is used to demonstrate the efficiency and effectiveness of the proposed algorithms moreover the proposed algorithms can also be used to obtain the optimal portfolio containing large numbers of securities which is not possible or at least is complicated via traditional quadratic programming approaches

mean variance analysis of a single supplier and retailer supply chain under a returns policy abstract in the literature most of the supply chain coordinating policies target at improving the supply chain s efficiency in terms of expected cost reduction or expected profit improvement however optimizing the expected performance alone cannot guarantee that the realized performance measure will fall within a small neighborhood of its expected value when the corresponding variance is high moreover it ignores the risk aversion of supply chain members which may affect the achievability of channel coordination as a result we carry out in this paper a mean variance mv analysis of supply chains under a returns policy we first propose an mv formulation for a single supplier single retailer supply chain with a newsvendor type of product the objective of each supply chain decision maker is to maximize the expected profit such that the standard deviation of profit is under the decision maker s control we study both the cases with centralized and decentralized supply chains we illustrate how a returns policy can be applied for managing the supply chains to address the issues such as channel coordination and risk control extensive numerical studies are conducted and managerial findings are proposed

analysis of the conditional stock return distribution under incomplete specification abstract the analysis of the distribution of the stock returns plays an important role in financial theory since a distributional assumption is required for mean variance portfolio theory theoretical models of capital asset prices determining the price of derivative products efficient estimation by maximum likelihood procedure and establishing forecasting confidence intervals up to now most of the studies analyze the unconditional distribution of the stock returns using the likelihood ratio test the schwarz information criterion or by graphical analysis however the analysis of the conditional distribution is very important since most of the empirical financial studies use high frequency data and these data present dynamic structure in this paper we focus on the conditional distribution we design different bootstrap mechanisms for comparing the goodness of fit of several functional forms postulated under the null hypothesis for individual spanish stocks and for the general index of the madrid stock market we use the cramer von mises test statistic based on the standardized residuals and assuming that the null distribution can depend on some unknown parameters

the transfer of human capital abstract most of our productive knowledge was handed down to us by previous generations the transfer of knowledge from the old to the young is therefore a cornerstone of productivity growth we study this process in a model in which the old sell knowledge to the young old agents train the young and charge them for this service we take an information theoretic approach in which training occurs if a young agent watches an old agent perform a task equilibrium is not constrained pareto optimal the old have private information and this gives rise to an adverse selection problem some old agents manage to sell skills that the planner would prefer to extinguish so as to allow more young agents to start new technologies in this sense there is too much resistance to change

anticipation effects of technological progress on capital accumulation a vintage capital approach abstract due to embodied technological progress new generations of capital goods are more productive therefore in order to study the effects of technological progress a model must be analyzed in which different generations of capital goods can be distinguished we determine in what way the firm adjusts current investments to predictions of technological progress in the presence of market power we show that a negative anticipation effect occurs i e current investments in recent generations of capital goods decline when faster technological progress will take place in the future because then it becomes more attractive to wait for new generations of capital goods in case that only investments in new machines are possible actually a whole wave of anticipation phases arises

financing durable assets this paper studies the nancing of durable assets in a model with collateral constraints due to limited enforcement durability aects the ease of nancing we show that more durable assets require larger down payments of internal funds per unit of capital making them harder to nance because durability raises the price of an asset and hence the overall nancing need more than its collateral value thus nancial constraints have a bigger impact on purchases of more durable capital such as land structures and durable equipment this basic insight has implications for the choice between new and used capital technology adoption and the rent versus buy decision since new assets are more durable than used ones unconstrained borrowers buy new assets and sell them when they are used while constrained borrowers purchase used assets financial constraints inhibit technology adoption as constrained borrowers may adopt less durable low quality assets that are otherwise dominated technologies more durable assets are more likely to be rented given their larger nancing need legal enforcement aects trade in durable assets and technology adoption with weak legal enforcement economies being net importers of used assets and investing a larger fraction in less durable low quality assets

frictionless technology diffusion the case of tractors many new technologies display long adoption lags and this is often interpreted as evidence of frictions inconsistent with the standard neoclassical model we study the diffusion of the tractor in american agriculture between 1910 and 1960 a well known case of slow diffusion and show that the speed of adoption was consistent with the predictions of a simple neoclassical growth model the reason for the slow rate of diffusion was that tractor quality kept improving over this period and more importantly that only when wages increased did it become relatively unprofitable to operate the alternative laborintensive horse technology jel l62 n51 n52 n71 n72 o33 q11 understanding the determinants of the rate at which new technologies are created and adopted is a critical element in the analysis of growth even though modeling equilibrium technology creation can be somewhat challenging for standard economic theory understanding technology adoption should not be specifically once the technology is available the adoption decision is equivalent to picking a point on the appropriate isoquant dynamic considerations make this calculation more complicated but they still leave it in the realm of the neoclassical model a simple minded application of the theory of the firm suggests that profitable innovations should be adopted instantaneously or with some delay depending on various forms of cost of adjustment the evidence on the adoption of new technologies seems to contradict this prediction jovanovic and lach 1997 report that for a group of 21 innovations it takes 15 years for its diffusion to go from 10 percent to 90 percent the 10 90 lag they also cite the results of a study by grubler 1991 covering 265 innovations who finds that for most diffusion processes the 10 90 lag is between 15 and 30 years 1

learning by doing and the choice of technology the role of patience if agents learn by doing and are myopic less advanced firms might adopt new technologies while more advanced firms would stick with the old technology this kind of overtaking can also occur if agents are forward looking and have high discount rates however overtaking never occurs if agents are sufficiently patient a finite discount rate increases the set of states at which agents adopt new technologies so more patient agents tend to upgrade their technology more frequently journal of economic literature classification numbers d92 o14 o33

on the unimodality of the price setting newsvendor problem with additive demand under risk considerations abstract we present a mean variance analysis of the single product single period price setting newsvendor problem with additive price dependent demand the main goal of this paper is to use a mean variance framework to solve any risk sensitive instance and find conditions under which the unimodality of the problem is guaranteed we introduce such conditions via the lost sales rate elasticity the elasticity of the optimal price and the elasticity of the expected safety stock surplus to provide managerial insight in terms of the newsvendor s level of service we also simplify the optimization problem in case that those conditions do not hold the main contribution of this paper is that by evaluating the unimodality of the problem for any possible risk attitude it extends previously published results found for the concavity of the solution in risk neutral and moderately risk sensitive cases

what s your identification strategy innovation in corporate finance research we study the diffusion of techniques designed to identify causal relationships in corporate finance research we estimate that the diffusion started in the mid 1990s lagged 20 years compared to economics and is now used in the majority of corporate finance articles consistent with recent theories of technology diffusion the adoption varies across researchers based on individuals expected net benefits of adoption younger scholars holders of phds in economics and those working at top institutions adopt faster adoption is accelerated through networks of colleagues and alumni and is also facilitated by straddlers who cross over from economics to finance our findings highlight new forces that explain the diffusion of innovation and shape the norms of academic research this paper was accepted by gustavo manso finance

robust tracking error portfolio selection with worst case downside risk measures abstract this paper proposes downside risk measure models in portfolio selection that captures uncertainties both in distribution and in parameters the worst case distribution with given information on the mean value and the covariance matrix is used together with ellipsoidal and polytopic uncertainty sets to build up this type of downside risk model as an application of the models the tracking error portfolio selection problem is considered by lifting the vector variables to positive semidefinite matrix variables we obtain semidefinite programming formulations of the robust tracking portfolio models numerical results are presented in tracking sse50 of the shanghai stock exchange compared with the tracking error variance portfolio model and the equally weighted strategy the proposed models are more stable have better accumulated wealth and have much better sharpe ratio in the investment period for the majority of observed instances

non separation in the mean lower partial moment portfolio optimization problem abstract with a number of advantages lower partial moments lpm serve as alternatives to variance as measures of portfolio risk for two specific targets a separation property holds in the context of mean lpm portfolio optimization that allows investors to separate the decision about investment proportions among risky assets from the decision about how much to invest in risky versus risk free assets for other targets however separation is not guaranteed and this case has not received much attention in the literature we show in the case of non separation that investment curves are not common to all optimizing investors but that they are convex in mean lpm space and their lower envelope is the efficient frontier we consider the interesting behavior of investment curves and optimal risky portfolios we also show empirically that an investor who mistakenly assumes separation holds will not experience significant excess portfolio risk in all practical cases

sustainable economic development and the environment theory and evidence the relationship between growth and pollution is studied through a vintage capital model where new technologies are more environmentally friendly we find that once the optimal scrapping age of technologies is reached an economy may achieve two possible cases of sustainable development one in which pollution falls and another in which it stabilizes or a catastrophic outcome where environmental quality reaches its lower bound the outcome will depend on countries investment path and their propensity to innovate in environmentally clean technologies both of which are likely to differ across economies empirical results using long time series for a number of developed and developing countries indeed confirm heterogenous experiences in the pollution output relationship

keeping up with the technology pace a dns curve and limit cycle in a technology investment decision problem abstract in order to keep up with its economic environment a firm should respond to new technological developments in this paper we establish the optimal technology investment decision within a dynamic model in which the baseline technology level rises over time the problem is analyzed by designing a two state optimal control model it turns out that in the state space a dechert nishimura skiba dns curve can be determined that separates different long run outcomes viz zero investment constant positive investment or a cyclical sequence of zero and positive investment

occupational mobility and wage inequality in this article we argue that wage inequality and occupational mobility are intimately related we are motivated by our empirical findings that human capital is occupation specific and that the fraction of workers switching occupations in the u s was as high as 16 a year in the early 1970 s and had increased to 21 by the mid 1990 s we develop a general equilibrium model with occupation specific human capital and heterogeneous experience levels within occupations we find that the model calibrated to match the level of occupational mobility in the 1970 s accounts quite well for the level of within group wage inequality in that period next we find that the model calibrated to match the increase in occupational mobility accounts for over 90 of the increase in wage inequality between the 1970 s and the 1990 s the theory is also quantitatively consistent with the level and increase in the short term variability of earnings copyright wiley blackwell

entry exit and diffusion with learning by doing early entry has the advantage of higher revenues per unit of output early on late entry has the benefit of learning from the experience of earlier entrants and hence lower production costs the advantages are balanced off in a continuous time perfect foresight equilibrium competition generates s shaped diffusion and staggered entry and exit a monopolist will innovate less than a competitive industry but the innovation that he does do he will do sooner copyright 1989 by american economic association

technical change and the demand for skills during the second industrial revolution evidence from the merchant marine 1891 1912 abstract using a large individual level wage data set we examine the impact of a major technological innovation the steam engine on the demand for skills in the merchant shipping industry we find that the technical change created a new demand for engineers a skilled occupation it had a deskilling effect on production work moderately skilled able bodied seamen were replaced by unskilled engine room operatives on the other hand able bodied seamen carpenters and mates employed on steam vessels earned a premium relative to their counterparts on sail vessels and this appears partly related to skill

international portfolio diversification with estimation risk international portfolio diversification has long been advocated as a way of enhancing average returns while reducing portfolio risk for the investor who considers diversifying into foreign securities this proposition however relies on the assumption that the required inputs to the classical mean variance analysis are known with certainty typically expected returns variances and covariances are simply replaced by their ex post sample values and the optimal portfolio is derived without mentioning the uncertainty inherent in these parameter values but the rational investor should take this uncertainty into account when forming expectations and probably will consider estimators that are less subject to estimation error than the classical sample mean this paper investigates alternative estimators of expected returns and their implications for the alleged gains from diversification an important observation is the crucial influence that errors in estimating expected returns have on portfolio analysis a closer examiprevious studies of international portfolio diversification have relied on ex post meanvariance analysis without considering the problem of estimation risk typically past averages are substituted for expected returns and no allowance is made for the uncertainty inherent in these parameter values first i demonstrate the shortcomings of such an approach and second i investigate another method of estimating expected returns initially proposed by stein by shrinking the sample averages toward a common mean i find that the out of sample performance of the optimal portfolio is substantially increased one of the implications of this method is that the classical conclusions vastly overestimate the possible gains in average returns instead benefits from diversification are more likely to accrue from a reduction in risk this paper draws on part of my dissertation at the university of chicago i am grateful to arnold zellner michael mussa george constantinides and especially john bilson for useful discussions and comments numerous improvements were also suggested by the referee this research received the generous financial support of the college interuniversitaire d etudes doctorales dans les sciences du management

portfolio optimization under lower partial moments in emerging electricity markets evidence from turkey abstract optimization of the electricity markets under modern portfolio theory has a crucial role for financial decision makers power suppliers in deregulated electricity markets need to optimize their generation capacities and bidding strategies so as to effectively participate in bilateral contract and spot markets market players have to deal with continuously changing electricity prices in competitive electricity market environment during their daily routine system operations electricity not like the others is a unique product service and cannot be stored economically however it should be generated and consumed simultaneously in addition to all power suppliers face with fuel price water regime delivery and network risks in view of the scene described above prudent decision making methodologies are of critical importance to maximize profit while minimizing managing risks this paper presents a comprehensive comparison of mean variance down side and semi variance methods for optimization in electricity markets and the corresponding methodologies to maximize the return while minimizing risk real turkish day ahead market data set between december 2009 and december 2012 is used in numerical calculations generation cost data of hydraulic plants lignite coal fired thermal power plants and natural gas combined cycle power plants are taken into consideration in the course of optimization evaluations in the present of real data these methods can also be applied to renewable energy generation types these three methods were able to be applied to all case scenarios effectively and produced efficient frontiers optimal minimal portfolios and utility functions successfully the results have revealed that the methods significantly provide decisions for power suppliers with different risk aversion levels and for various instruments to maximize the profit while minimizing the associated market risks and to meet generation obligations consequently financial optimization under lower partial moments constraints would give notable results in analyzing the efficient frontiers for electricity markets in turkey

portfolio optimization under loss aversion abstract we present an integrated methodological approach for selecting portfolios the proposed methodology is focused on incorporation of investor s preferences in the mean risk framework we propose a risk measure calculated with the downside part of the portfolio return distribution which we argue captures better the practical behavior of the loss averse investor we establish its properties study the link with stochastic dominance criteria point out the relations with conditional value at risk and lower partial moment of first order and give the explicit formula for the case of scenario based portfolio optimization the proposed methodology involves two stages firstly the investment opportunity set efficient frontier is determined and secondly one single preferred efficient portfolio is selected namely the one having the highest expected utility value three classes of utility functions with loss aversion corresponding to three types of investors are considered the empirical study is targeted on assessing the differences between the efficient frontier of the proposed model and the classical mean variance mean cvar and mean lpm1 frontiers we firstly analyze the loss of welfare incurred by using another model instead of the proposed one and measure the corresponding gain loss of utility secondly we assess how much the portfolios really differ in terms of their compositions using a dissimilarity index based on the 1 norm we describe and interpret the optimal solutions obtained and emphasize the role and influence of loss aversion parameters values and of constraints three types of constraints are studied no short selling allowed a certain degree of diversification imposed and short selling allowed

on the diffusion of new technology a game theoretic approach this paper is an attempt at a rigorous albeit not exceedingly general analysis of the diffusion of new technology in particular consider an industry composed of two firms each using the current best practice technology the firms are assumed to be operating at nash equilibrium output levels generating a market price given demand and profit allocations when a cost reducing innovation is announced each firm must determine when if ever to adopt it based in part upon the discounted cost of implementing the new technology and in part upon the behavior of the rival firm if either firm adopts before the other it can expect to make substantial profits at the expense of the other firm on the other hand the discounted sum of purchase price and adjustment costs may decline with the lengthening of the adjustment period as various quasi fixed factors become more easily variable therefore although waiting costs the firm more in terms of foregone profits it may save money on the cost of purchasing the new technology thus the firm must weigh the costs and benefits of delaying adoption as well as take account of its rival s strategic behavior

var and expected shortfall in portfolios of dependent credit risks conceptual and practical insights in the first part of this paper we address the non coherence of value at risk var as a risk measure in the context of portfolio credit risk and highlight some problems which follow from this theoretical deficiency in particular a realistic demonstration of the non subadditivity of var is given and the possibly nonsensical consequences of var based portfolio optimisation are shown the second part of the paper discusses var and expected shortfall estimation for large balanced credit portfolios all standard industry models creditmetrics kmv creditrisk are presented as bernoulli mixture models to facilitate their direct comparison for homogeneous groups it is shown that measures of tail risk for the loss distribution may be approximated in large portfolios by analysing the tail of the mixture distribution in the bernoulli representation an example is given showing that for portfolios of lower quality choice of model has some impact on measures of extreme risk 2002 elsevier science b v all rights reserved

vested interests in a positive theory of stagnation and growth we study a positive theory of stagnation and growth aimed at understanding the large variations in growth outcomes across actual economies the theory points to the fundamental role played by vested interests in determining policies which are key to the growth process some agents seek to prevent the adoption of new technologies we develop a model of technology adoption and show how technological innovation may sow the seeds of its own destruction in particular we find that the equilibrium is characterized by a long cycle of stagnation and growth over this cycle incumbents are phased out of the economy will new innovation occur in formalizing our theory we make a methodological contribution by characterizing dynamic voting equilibria when voters must forecast the effects of different current policies on future prices and policy outcomes

volatility and slow technology diffusion abstract i study the effects of uncertainty on technology adoption and thereby on volatility and growth i present an analytically tractable model in which i uncertainty about the returns to adoption delays technology diffusion and ii the mean and volatility of output growth are jointly determined in equilibrium i then test the key predictions of the model by studying the introduction of three major information and communication technologies icts computers internet and cell phones i find that countries with more volatile growth rates of real gdp per capita have higher time adoption lags and lower average growth as predicted by the model

the culture of entrepreneurship abstract we study the cultural process through which a society inculcates an entrepreneurial spirit people work for a guaranteed wage or operate a firm whose risky return depends on business expertise the latter is culturally acquired within the family or outside and people may choose an occupation different from the one they were socialized into a cultural bias towards safer occupations from colonial and post colonial policies leads to stagnation where entrepreneurs do not upgrade technology because of their proficiency with existing methods an aggregate productivity shock can tip this economy towards growth led by established businesses a human capital shock where existing business expertise is less useful is more disruptive growth occurs through the emergence of a new class of entrepreneurs we conclude that culture is not destiny it adapts even when some cultural traits do not

mean lower partial moment valuation and lognormally distributed returns in this paper we develop a capital asset pricing model in a mean lower partial moment framework specifically we show that when partial moments are computed about the expected risky portfolio return optimal portfolio choice in a mean lower partial framework permits a two fund portfolio separation between a riskless asset and a market portfolio of risky assets in this new framework risk is measured as semideviation for second degree stochastic dominance and semivariance for third degree stochastic dominance further when security returns are lognormally distributed and small risk this new mean lower partial moment valuation specializes to the mean logarithmic variance capital asset pricing model

the economics of new blood abstract we construct a dynamic general equilibrium model of search and matching where public knowledge grows through time and workers accumulate a fraction of this knowledge through education retraining due to search delays the unemployment pool is populated by vintages of workers of differing productivities through intergenerational rivalry the human capital of older generations is rendered obsolete relative to that of the new blood higher knowledge growth exacerbates intergenerational competition thereby lowering education and growth while raising unemployment and inequality these findings help explain wage compression expansion and the hump shaped wage tenure profile across cohorts

a risk return model with risk and return measured as deviations from a target return two attribute risk and return models are very popular in the economics and finance literature for analyzing decisions under uncertainty their popularity stems primarily from the intuitive appeal of the dichotomy into risk and return and from the ease with which the concepts can be diagrammed in two dimensions the most commonly used risk return model is the mean variance model in which risk is measured as the variance and return by the mean of the probability distribution over outcomes the mean variance model has a number of shortcomings which are widely known but of particular concern here are the facts that 1 mean variance dominance is neither necessary nor sufficient for second degree stochastic dominance 2 unless the form of the probability distribution is restricted mean variance is consistent with von neumann morgenstern utility theory only if the utility function is quadratic and 3 as peter fishburn has noted

the diffusion of computers and the distribution of wages abstract when the costs are decreasing workers adopt technology at the point where the costs equal the increased productivity output per worker increases immediately while productivity benefits increase only gradually if costs continue to fall as a result workers in computer adopting labor market groups experience an immediate fall in wages due to increased supply on the other hand adopting workers experience wage increases with some delay this model explains why increased computer use does not immediately lead to higher wage inequality more specifically the results of the model are shown to be consistent with the question why within group wage inequality among skilled workers as a result of computer technology adoption in the united states increased in the 1970s while between group wage inequality and within group wage inequality among the unskilled did not start to increase until the 1980s the model also predicts that the more compressed german wage structure leads to a lagged diffusion of computer technology along with smaller changes in wage inequality our empirical analysis suggests that this is consistent with the actual developments in germany since the 1980s finally the theoretical predictions seem to be of the right magnitude to explain the empirical quantities observed in the data

variance vs downside risk is there really that much difference abstract the popularity of downside risk among investors is growing and mean return downside risk portfolio selection models seem to oppress the familiar mean variance approach the reason for the success of the former models is that they separate return fluctuations into downside risk and upside potential this is especially relevant for asymmetrical return distributions for which mean variance models punish the upside potential in the same fashion as the downside risk the paper focuses on the differences and similarities between using variance or a downside risk measure both from a theoretical and an empirical point of view we first discuss the theoretical properties of different downside risk measures and the corresponding mean downside risk models against common beliefs we show that from the large family of downside risk measures only a few possess better theoretical properties within a return risk framework than the variance on the empirical side we analyze the differences between some us asset allocation portfolios based on variances and downside risk measures among other things we find that the downside risk approach tends to produce on average slightly higher bond allocations than the mean variance approach furthermore we take a closer look at estimation risk viz the effect of sampling error in expected returns and risk measures on portfolio composition on the basis of simulation analyses we find that there are marked differences in the degree of estimation accuracy which calls for further research

technical progress and early retirement this paper claims that technical progress induces early retirement of older workers it presents a model where human capital is technology specific so that technical progress erodes some existing human capital this affects mostly older workers who have a smaller incentive to learn the new technology since their career horizon is shorter hence they tend to work less we find support to this erosion effect in hrs data which shows that retirement and unemployment of older workers are positively related to technical progress in their sectors unlike the effect across sectors the model is ambiguous about the aggregate effect of technical progress on labor supply of older workers while in sectors with many innovations it falls due to the erosion effect in other sectors it increases due to higher wages to examine which effect dominates we run a time series test using us data and find that the rate of average technical progress reduces aggregate labor force participation by the old namely the erosion effect dominates

bargaining over new ideas the distribution of rents and the stability of innovative firms we develop a theory of the rent distribution and stability of innovative firms our theory is based on a model of bargaining over new ideas the model accounts for the problem of information leakage namely the diffusion of information about new ideas among the agents that participate in the bargaining our main results draw a link between the strength of intellectual property rights enforcement and the distribution of rents in firms as well as between the size and organization of firms and their stability our theory explains why small firms are advantaged in introducing innovation into the market and why spin outs tend to emerge from large established firms jel l1 l2 c7

vintage human capital demographic trends and endogenous growth we study how economic growth is affected by demographics in an overlapping generations model with a realistic survival law individuals optimally chose the dates at which they leave school to enter the labor market and at which they retire endogenous growth arises thanks to the accumulation of generation specific human capital favorable shifts in the survival probabilities always induce longer schooling and later retirement but have an ambiguous effect on growth the relationship between the growth of population and per capita growth is hump shaped increases in longevity can be responsible for a switch from a no growth regime to a sustained growth regime and for a positive relationship between fertility and growth to vanish

the impact of financial leverage on risk of equity measured by loss oriented risk measures an option pricing approach abstract we investigate how financial leverage influences the risk of equity in companies with limited liability in our study the risk is measured by loss oriented risk measures var downside deviation etc also the dependence of the risk premium on risk is under consideration var based and downside risk measures are considered in similar frameworks and risk premium is introduced which is symmetrical to these risk measures the value of equity is modeled by the price of a call option in most cases there is a positive relationship between the level of leverage measured by the debt ratio and the risk measured by the loss oriented risk measures however there exist exceptions the risk premium is not a linear function of the risk still for a reasonable range of leverage the dependence of the risk premium on risk is approximately linear in most cases

optimal algorithms and lower partial moment ex post results portofolio management in the finance literature has typically used optimization algorithms to determine security allocations within a portfolio in order to obtain the best trade off between risk and return these algorithms despite some improvements are restrictive in terms of an investor s risk aversion utility function since individual investors have different levels of risk aversion this paper proposes two portfolio optimization algorithms that can be tailored to the specific level of risk aversion of the individual investor and performs ex postevaluation tests of the algorithm performance