bank runs liquidity costs and investment distortions abstract in this paper we extend the diamond and dybvig 1983 model of intermediation to study further the conditions under which bank runs can occur and to consider how private parties might adjust to the existence of bank run equilibria we provide weaker necessary conditions for runs we then characterize how banks respond to the possibility of runs in their design of deposit contracts and investment decisions banks might choose to offer contracts that prevent runs but under some conditions the second best contracts will involve accepting some risk of runs in order to achieve higher expected returns from their investments

index changes and losses to index fund investors because of arbitrage around the time of index changes investors in funds linked to the s p 500 index and the russell 2000 index lose between 1 0 billion and 2 1 billion a year for the two indices combined the losses can be higher if benchmarked assets are considered the pre reconstitution period is lengthened or involuntary deletions are taken into account the losses are an unexpected consequence of the evaluation of index fund managers on the basis of tracking error minimization of tracking error coupled with the predictability and or pre announcement of index changes creates the opportunity for a wealth transfer from index fund investors to arbitrageurs

portfolio optimization with tracking error constraints this article explores the risk and return relationship of active portfolios subject to a constraint on tracking error volatility tev which can also be interpreted in terms of value at risk such a constrained portfolio is the typical setup for active managers who are given the task of beating a benchmark the problem with this setup is that the portfolio manager pays no attention to total portfolio risk which results in seriously inefficient portfolios unless some additional constraints are imposed the development in this article shows that tev constrained portfolios are described by an ellipse on the traditional mean variance plane this finding yields a number of new insights because of the flat shape of this ellipse adding a constraint on total portfolio volatility can substantially improve the performance of the active portfolio in general plan sponsors should concentrate on controlling total portfolio risk

another look at portfolio optimization under tracking error constraints research has shown that adding constraints to total portfolio volatility can substantially improve the performance of managed portfolios although other work has considered constant tracking error volatility frontiers in this study tracking error was allowed to vary but the risk aversion was fixed the resulting optimal portfolios have several desirable properties

portfolio selection with mental accounts and delegation das et al 2010 develop an elegant framework where an investor selects portfolios within mental accounts but ends up holding an aggregate portfolio on the mean variance frontier this investor directly allocates the wealth in each account among available assets in practice however investors often delegate the task of allocating wealth among assets to portfolio managers who seek to beat certain benchmarks accordingly we extend their framework to the case where the investor allocates the wealth in each account among portfolio managers our contribution is threefold first we provide an analytical characterization of the existence and composition of the optimal portfolios within accounts and the aggregate portfolio second we present conditions under which such portfolios are not on the mean variance frontier and conditions under which they are third we show that the aforementioned analytical characterization is also applicable within the framework of das et al and thus improves upon their numerical approach

portfolio selection based on return risk and relative performance markowitz introduced the concept of portfolio selection based on return and variance recognition that many investors evaluate performance relative to a benchmark led to the idea of portfolio selection based on return and relative risk for many investors both approaches fail to yield satisfactory results although they acknowledge the importance of benchmarks in the decision process they are not indifferent to the variance of absolute returns in this situation a utility function that measures return variance and tracking error is more appropriate analysis of this utility function shows that its set of efficient portfolios includes the mean variance efficient set the mean tracking error efficient set and all convex combinations of these two sets optimization with this utility function may find solutions that investors will actually use

basel s value at risk capital requirement regulation an efficiency analysis abstract we analyze the optimal portfolio policies of expected utility maximizing agents under var capital requirement var cr regulation in comparison to the optimal policy under exogenously imposed var limit var l and limited expected loss lel regulations with var cr regulation the agent strategy consists of simultaneous decisions on both the portfolio var and on the implied amount of required eligible capital as a result the performance of var cr regulation depends on its design the parameter n and the agent preferences we show that an optimal var cr regulation allows the regulator on the one hand to completely eliminate the exposure to the largest losses which may jeopardize the existence of the institution and on the other hand to restrain the portfolio exposure to all other losses these results rationalize the current basel regulations however the analysis shows also that there is an optimal level of required eligible capital from the regulator standpoint counter intuitively any requirement above this optimal level is inefficient as it leads to a smaller amount of actually maintained eligible capital and thereby to a larger exposure to the most adverse states of the world unfortunately the current basel s range of required levels n 3 4 is within this inefficient range moreover with an inefficient regulation the agent might employ an inefficient reporting and disclosure procedure

incentive fees who wins who loses 1987 incentive fees who wins who loses financial analysts journal vol 43 no 1 pp 27 38

portfolio selection with a drawdown constraint abstract when identifying optimal portfolios practitioners often impose a drawdown constraint this constraint is even explicit in some money management contracts such as the one recently involving merrill lynch management of unilever s pension fund in this setting we provide a characterization of optimal portfolios using mean variance analysis in the absence of a benchmark we find that while the constraint typically decreases the optimal portfolio s standard deviation the constrained optimal portfolio can be notably mean variance inefficient in the presence of a benchmark such as in the merrill lynch unilever contract we find that the constraint increases the optimal portfolio s standard deviation and tracking error volatility thus the constraint negatively affects a portfolio manager s ability to track a benchmark

active portfolio management with benchmarking adding a value at risk constraint abstract we examine the impact of adding a value at risk var constraint to the problem of an active manager who seeks to outperform a benchmark while minimizing tracking error variance tev by using the model of roll 1992 a mean variance analysis of tracking error journal of portfolio management 18 13 22 we obtain three main results first portfolios on the constrained mean tev boundary still exhibit three fund separation but the weights of the three funds when the constraint binds differ from those in roll s model second the constraint mitigates the problem that when an active manager seeks to outperform a benchmark using the mean tev model he or she selects an inefficient portfolio finally when short sales are disallowed the extent to which the constraint reduces the optimal portfolio s efficiency loss can still be notable but is smaller than when short sales are allowed

management compensation and market timing under portfolio constraints abstract this paper shows that portfolio constraints have important implications for management compensation and performance evaluation in particular in the presence of portfolio constraints allowing for benchmarking can be beneficial benchmark design arises as an alternative effort inducement mechanism vis a vis relaxing portfolio constraints numerically we solve jointly for the manager s linear incentive fee and the optimal benchmark the size of the incentive fee and the risk adjustment in the benchmark composition are increasing in the investor s risk tolerance and the manager s ability to acquire and process private information

interest rates and financial fragility abstract how do the interest rates banks earn on their assets affect the susceptibility of the banking system to a self fulfilling run by depositors i study this question in a version of the model of diamond and dybvig 1983 with limited commitment and a non trivial portfolio choice i show that the relationship between these interest rates and financial fragility is often non monotone for example a small increase in the return on illiquid investment or a small increase in the term premium may raise banks susceptibility to a run while a larger increase would make the banking system more stable the same is true for changes in short term rates holding the longer term rates fixed i provide a precise characterization of these comparative statics of financial fragility

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

preindustrial and postwar economic development is there a link everybody knows now that the hardware dimension of development the physical infrastructure for example is a lot easier to put in place than the software to keep it operable which depends on local skills and institutions united nations development programme 1

portfolio frontiers with restrictions to tracking error volatility and value at risk abstract asset managers are often given the task of restricting their activity by keeping both the value at risk var and the tracking error volatility tev under control however these constraints may be impossible to satisfy simultaneously because var is independent of the benchmark portfolio the management of these restrictions is likely to affect portfolio performance and produces a wide variety of scenarios in the risk return space the aim of this paper is to analyse various interactions between portfolio frontiers when risk managers impose joint restrictions upon tev and var specifically we provide analytical solutions for all the intersections and we propose simple numerical methods when such solutions are not available finally we introduce a new portfolio frontier

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

does it all add up benchmarks and the compensation of active portfolio managers in this article the authors examine theoretically the use of benchmark portfolios in the compensation of privately informed portfolio managers they find that the use of a benchmark and particularly the types of benchmarks often observed in practice cannot be easily rationalized specifically commonly used benchmark adjusted compensation schemes are generally inconsistent with optimal risk sharing and do not lead to the choice of an optimal portfolio for the investor moreover benchmarks do not help in solving potential contracting problems such as inducing the manager to expend effort or trying to screen out uninformed managers copyright 1997 by university of chicago press

equilibrium bank runs we analyze a banking system in which the class of feasible deposit contracts or mechanisms is broad the mechanisms must satisfy a sequential service constraint but partial or full suspension of convertibility is allowed consumers must be willing to deposit ex ante we show by examples that under the so called optimal contract the postdeposit game can have a run equilibrium given a propensity to run triggered by sunspots the optimal contract for the full predeposit game can be consistent with runs that occur with positive probability thus the diamond dybvig framework can explain bank runs as emerging in equilibrium under the optimal deposit contract

optimizing tracking error constrained portfolios active portfolios subject to tracking error te constraints are the typical setup for active managers tasked with outperforming a benchmark the risk and return relationship of such constrained po

incentive fees some problems and some solutions 1987 incentive fees some problems and some solutions financial analysts journal vol 43 no 1 pp 21 26

a linear model for tracking error minimization abstract this article investigates four models for minimizing the tracking error between the returns of a portfolio and a benchmark due to linear performance fees of fund managers we can argue that linear deviations give a more accurate description of the investors risk attitude than squared deviations all models have in common that absolute deviations are minimized instead of squared deviations as is the case for traditional optimization models linear programs are formulated to derive explicit solutions the models are applied to a portfolio containing six national stock market indexes usa japan uk germany france switzerland and the tracking error with respect to the msci morgan stanley capital international index world stock market index is minimized the results are compared to those of a quadratic tracking error optimization technique the portfolio weights of the optimized portfolio and its risk return properties are different across the models which implies that optimization models should be targeted to the specific investment objective finally it is shown that linear tracking error optimization is equivalent to expected utility maximization and lower partial moment minimization