equilibrium in an ambiguity averse mean variance investors market abstract in a financial market composed of n risky assets and a riskless asset where short sales are allowed and mean variance investors can be ambiguity averse i e diffident about mean return estimates where confidence is represented using ellipsoidal uncertainty sets we derive a closed form portfolio rule based on a worst case max min criterion then in a market where all investors are ambiguity averse mean variance investors with access to given mean return and variance covariance estimates we investigate conditions regarding the existence of an equilibrium price system and give an explicit formula for the equilibrium prices in addition to the usual equilibrium properties that continue to hold in our case we show that the diffidence of investors in a homogeneously diffident with bounded diffidence mean variance investors market has a deflationary effect on equilibrium prices with respect to a pure mean variance investors market in equilibrium deflationary pressure on prices may also occur if one of the investors in an ambiguity neutral market with no initial short position decides to adopt an ambiguity averse attitude we also establish a capm like property that reduces to the classical capm in case all investors are ambiguity neutral

tax adjusted discount rates this paper develops models for discount rates that are adjusted for the interest tax shields of an infra marginal firm in a general tax equilibrium where there is cross sectional variation in corporate tax rates under the assumption that the firm optimally maintains a predetermined debt ratio a tax adjusted riskless discount rate model is given for valuing certainty equivalents and a tax and risk adjusted discount rate model is given for valuing expected cash flows for the latter case the asset equity debt and tax shield betas are derived and a weighted average cost of capital interpretation is given the tax adjusted capm apt security market lines for expected returns in stock and bond markets both have the same slope but different intercepts a formula is also provided for the present value of the interest tax shield when the firm optimally maintains a predetermined debt level the analysis here also differs from the existing literature in the following respects it allows for cross sectional variation in corporate tax rates and personal tax rates it shows that the market values of risky and riskless interest tax shields differ only to the extent that tax laws provide for nonlinear taxation of gains and losses it also shows that interest tax shields should be discounted at a tax adjusted discount rate that reflects the fact that they accrue to equity investors rather than debt investors continuous time simplifications of the formulas in this paper and the previous literature are also given

delta hedging strategies comparison abstract in this paper we implement dynamic delta hedging strategies based on several option pricing models we analyze different subordinated option pricing models and we examine delta hedging costs using ex post daily prices of s p 500 furthermore we compare the performance of each subordinated model with the black scholes model

inverse portfolio problem with mean deviation model abstract a markowitz type portfolio selection problem is to minimize a deviation measure of portfolio rate of return subject to constraints on portfolio budget and on desired expected return in this context the inverse portfolio problem is finding a deviation measure by observing the optimal mean deviation portfolio that an investor holds necessary and sufficient conditions for the existence of such a deviation measure are established it is shown that if the deviation measure exists it can be chosen in the form of a mixed cvar deviation and in the case of n risky assets available for investment to form a portfolio it is determined by a combination of n 1 cvar deviations in the later case an algorithm for constructing the deviation measure is presented and if the number of cvar deviations is constrained an approximate mixed cvar deviation is offered as well the solution of the inverse portfolio problem may not be unique and the investor can opt for the most conservative one which has a simple closed form representation

coordinated fuzzy constrained optimal power dispatch for bilateral contract balancing electricity and ancillary services markets this paper proposes a coordinated fuzzy constrained optimal power dispatch cfcopd algorithm for bilateral contract balancing electricity and ancillary services markets the cfcopd problem is decomposed into social welfare fuzzy maximization subproblem which is solved by mixed integer fuzzy linear programming miflp and combined reactive power cost and cost of real power loss fuzzy minimization subproblem which is solved by fuzzy linear programming flp the proposed cfcopd algorithm is tested on the modified ieee 30 bus system and the thai power 424 bus system the dispatch results show that the social welfare of the fuzzy constrained competitive electricity and ancillary services price ceasp scheme with bilateral contract curtailment bids is higher than those of competitive electricity price cep scheme and ceasp scheme with and without bilateral contract curtailment bids leading to a lower average electricity price

dynamic investment and financing under personal taxation this paper examines the effects of capital gains taxation on firms investment and financing decisions we develop a real options model in which the timing of investment the decision to default and the firm s capital structure are endogenously and jointly determined our analysis demonstrates that the asymmetric taxation of capital gains and losses fosters investment by eroding the option value of waiting it also shows that firms controlled by taxable investors employ more equity financing the higher the firm s stock price and the worse the firm s historical performance using a large sample of u s industrial firms that are owned by taxable investors between 1970 and 2008 we present new evidence on corporate investment and financing policies which is supportive of the model s predictions

arbitrage clientele effects and the term structure of interest rates this paper derives a new and intuitive estimation procedure for the term structure under potential tax arbitrage no a priori assumptions regarding the equality of the prices and present values of bonds are made the data are employed to determine whether this equality holds and an appropriate estimator is thereby endogenously derived the suggested estimator is based on the optimizing behavior of an investor in a market with frictions and emerges directly from the solution of the dual of the no arbitrage optimization problem in addition the proposed estimator benefits from being both theoretically sound and straightforward to apply

preference heterogeneity and asset prices an exact solution abstract we introduce a general equilibrium model of a multi agent pure exchange economy and find a set of conditions that enable us to obtain explicit closed form solutions to the equilibrium interest rate stock price risk premium and stock market volatility when investors have heterogenous risk aversions because the market is dynamically complete full risk sharing obtains and a representative agent can be constructed though the risk aversion of this agent fluctuates over time with the state of the economy as the relative wealth distribution of the individual investors changes we show that preference heterogeneity can cause asset prices to be significantly more volatile than the underlying dividends and that it can lead to leverage like effects in volatility in the sense that volatility increases after stock market declines

capm and apt like models with risk measures abstract the paper deals with optimal portfolio choice problems when risk levels are given by coherent risk measures expectation bounded risk measures or general deviations both static and dynamic pricing models may be involved unbounded problems are characterized by new notions such as strong compatibility between prices and risks surprisingly the lack of bounded optimal risk and or return levels arises for important pricing models black and scholes and risk measures var cvar absolute deviation etc bounded problems present a market price of risk and generate a pair of benchmarks from these benchmarks we introduce apt and capm like analyses in the sense that the level of correlation between every available security and some economic factors explains the security expected return the risk level non correlated with these factors has no influence on any return despite the fact that we are dealing with risk functions beyond the standard deviation

taxes on tax exempt bonds implicit tax rates priced in the cross section of municipal bonds are approximately two to three times as high as statutory income tax rates with implicit tax rates close to 100 using retail trades and above 70 for interdealer trades these implied tax rates can be identified because a portion of secondary market municipal bond trades involves income taxes after valuing the tax payments market discount bonds which carry income tax liabilities trade at yields around 25 basis points higher than com parable municipal bonds not subject to any taxes the high sensitivities of municipal bond prices to tax rates can be traced to individual retail traders dominating dealers and other institutions the issue of how taxes affect asset prices is an important issue in finance accounting and economics in theoretical models examining the effect of taxes

tax arbitrage restrictions and financial leverage clienteles abstract this paper argues that while total short sale constraints are often introduced to rule out tax arbitrage such constraints are both unrealistic and conceptually problematic instead milder constraints are advocated which prevent tax arbitrage while still allow short positions it is demonstrated that a model with these constraints employed can support bond pricing as in the miller equilibrium although it leads to a richer set of tax clienteles

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

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

optimal dispatch under transmission contracts open transmission access is now the most topical issue in power system deregulation power system operation poses the greatest challenge to a competitive environment incorporating open transmission access and there are some fundamental operational problems that are still unresolved this paper seeks to provide an approach to the power dispatch problem in a structure dominated by bilateral and multilateral transmission contracts a framework for price based operation under these conditions is developed and a methodology for optimal transmission dispatch is proposed the case study results illustrate that the proposed market arrangement and operating mechanisms are compatible with this new business environment

valuation of bankrupt firms this study compares the market value of firms that reorganize in bankruptcy with estimates of value based on management s published cash flow projections we estimate firm values using models that have been shown in other contexts to generate relatively precise estimates of value we find that these methods generally yield unbiased estimates of value but the dispersion of valuation errors is very widethe sample ratio of estimated value to market value varies from less than 20 to greater than 250 cross sectional analysis indicates that the variation in these errors is related to empirical proxies for claimholders incentives to overstate or understate the firm s value

the capital gain lock in effect and perfect substitutes abstract this paper analyses the effect of investors accrued capital gains on optimal portfolio composition and equilibrium returns under the assumption that investors are able to re balance with perfect substitute securities no dominance arguments are used to show that pricing differences because of accrued capital gains do not arise among securities which are perfect substitutes these arguments are insufficient however to prevent pricing differences because of accrued capital gains among securities which are not perfect substitutes trading rules are developed which outline the conditions necessary for the realisation of accrued capital gains and the deferral of capital losses these trading rules also provide guidance on which securities investors should sell given their tax basis when re balancing their portfolios

unbundling of transmission and ancillary services ii cost based pricing framework for pt i see ibid vol 12 no 2 1997 this paper presents a systematic framework for pricing transmission and ancillary services in competitive power markets this framework is based on the recovery of fixed and operating costs and it meets the traditional revenue requirements it is practical feasible easy to implement and to regulate it can be implemented with minimum transition cost this network flow dependent and nondiscriminatory framework is based on the decomposition approach presented in part i of this paper this decomposition forms an essential part of the proposed framework for usage based recovery of the fixed and operating costs the transmission system related fixed cost component is recovered from all transactions based on percentage utilization of the transmission system equipment the charge is based on the actual network power flows the ancillary service charge for a given transaction can be computed as the sum of the costs incurred at secondary generation for compensating the imbalance caused by that specific transaction the path providing function of the transmission grid is viewed as a true monopolistic service its pricing is cost based and charge for its use is usage based the generation based ancillary service supply can be made competitive its pricing is market based and charge for it is usage based a global overview of the proposed pricing strategy is analyzed in the context of other alternatives especially cost based methods a numerical example on a five bus system is given to illustrate the use of this pricing strategy

risk returns and values in the presence of differential taxation abstract we show that there exist separate security market lines smls for debt and equity securities in an equilibrium with differential taxation of debt and equity we characterize the conditions under which these smls have the same price of risk with different intercepts and the conditions under which the tax effect of leverage is linear in debt value as in the adjusted present value method we explore the implications of our results for cost of capital calculations how to calculate the cost of capital for debt and equity and how to unlever betas correctly accounting for differential taxation

optimal security design how should new securities be designed traditional theories have little to say on this the literature on capital structure and general equilibrium theories with incomplete markets take the securities firms issue as exogenous this paper explicitly incorporates the transaction costs of issuing securities and develops a model where the instruments that are traded are chosen optimally and the economy s market structure is endogenous among other things it is shown that the firm s income stream should be split so that in every state all payoffs are allocated to the security held by the group that values them most this abstract was borrowed from another version of this item

the dynamics of the volatility skew a kalman filter approach abstract much attention has been devoted to understanding and modeling the dynamics of implied volatility curves and surfaces this is crucial for both trading pricing and risk management of option positions we suggest a simple yet flexible model based on a discrete and linear kalman filter updating of the volatility skew from a risk management perspective we assess whether this model is capable of producing good density forecasts of daily returns on a number of option portfolios we also compare our model to the sticky delta and the vega gamma alternatives we find that it clearly outperforms both alternatives given its ability to easily account for movements of different nature in the volatility curve

two sided coherent risk measures and their application in realistic portfolio optimization by using a different derivation scheme a new class of two sided coherent risk measures is constructed in this paper different from existing coherent risk measures both positive and negative deviations from the expected return are considered in the new measure simultaneously but differently this innovation makes it easy to reasonably describe and control the asymmetry and fat tail characteristics of the loss distribution and to properly reflect the investor s risk attitude with its easy computation of the new risk measure a realistic portfolio selection model is established by taking into account typical market frictions such as taxes transaction costs and value constraints empirical results demonstrate that our new portfolio selection model can not only suitably reflect the impact of different trading constraints but find more robust optimal portfolios which are better than the optimal portfolio obtained under the conditional value at risk measure in terms of diversification and typical performance ratios

deposit market deregulation and interest rates the evolving deregulation of financial markets has sparked interest in the economic implications of increased flexibility in previously regulated markets much of the analysis has focused on deposit markets in which legislated maximum rates are being replaced by market determined equilibrium rates moreover because changes in deposit rates imply changes in the cost of funds to financial intermediaries concern has been voiced about the implications of deposit rate deregulation on the overall structure of interest rates specifically deregulation has been cited as one reason for the currently high rates of interest 2 in this paper we argue that this view of deregulation is flawed and we suggest that deregulation of deposit markets will lead to lower not higher loan and deposit rates furthermore we argue that previous analysis indicating that deposit deregulation leads to higher loan rates based on higher costs of funds to financial intermediaries depends on inadequate consideration of the role of implicit payments to depositors appropriate consideration of these implicit payments leads to results suggesting that deposit market deregulation should ceterus paribus lower loan rates the total cost of funds to banks falls as the interest rate ceiling is relaxed our theoretical results previewed here are admittedly at odds with some of the prior theoretical and empirical work on this issue our assumptions that the implicit deposit rate is flexible market determined and adjusts to clear the deposit market are crucial to our results

investor heterogeneity market segmentation leverage and the equity premium puzzle abstract financial economists for the past two decades have attempted to explain why the equity premium is so high now known as the equity premium puzzle epp we model investor heterogeneity market segmentation and optimal leverage using the time separable standard power utility market completeness and ignoring transaction costs to explain the epp we explain both the epp and the related risk free rate puzzle without resorting to preference modification furthermore we show a unique interior equilibrium for the debt ratio contrary to the work by f modigliani m h miller the cost of capital corporation finance and the theory of investment american economic review 48 1958 261 297 corporate income taxes and the cost of capital american economic review 53 1963 433 443 and s c myers presidential address the capital structure puzzle journal of finance 39 1984 575 592 our simulations show the relevance of our models

taxable and tax deferred investing a tax arbitrage approach we analyze an intertemporal portfolio problem with both taxable and tax deferred retirement accounts using a tax arbitrage argument we identify conditions under which the optimal location decision where to place an asset is separable from the allocation decision how much to allocate to each asset investors place highly taxed assets in the tax deferred account to maximize the tax benefit and adjust their taxable portfolios to achieve the optimal risk exposure we show that the two account problem can be reduced to a taxable account only problem the results are robust to capital gains tax deferrals consumption and contribution decisions and stochastic tax rates

using tucker s theorem of the alternative to simplify review and expand discrete arbitrage theory abstract for valuing derivatives and other assets in securities and commodities markets arbitrage pricing theory has been a major approach for decades this paper derives fundamental arbitrage pricing results in finite dimensions in a simple unified framework using tucker s theorem of the alternative frictionless results that is perfect market results plus imperfect market results such as those with dividends periodic interest payments transaction costs different interest rates for lending and borrowing shorting costs and constrained short selling are presented while the results are mostly known and appear in various places our contribution is to present them in a coherent and comprehensive fashion with very simple proofs the analysis yields a simple procedure to prove new results and some are presented for cases with imperfect market frictions

a general equilibrium theory of banks capital structure abstract we develop a general equilibrium theory of the capital structures of banks and firms the liquidity services of bank deposits make deposits a cheaper source of funding than equity in equilibrium banks pass on part of this funding advantage in the form of lower interest rates to firms that borrow from them firms and banks choose their capital structures to balance the benefits of debt financing against the risk of costly default an increase in the equity of a firm makes its debt less risky and that in turn reduces the risk of the banks who lend to the firm hence there is some substitutability between firm and bank equity we find that firms have a comparative advantage in providing a buffer against systemic shocks whereas banks have a comparative advantage in providing a buffer against idiosyncratic shocks

capital asset pricing model capm with drawdown measure the notion of drawdown is central to active portfolio management conditional drawdown at risk cdar is defined as the average of a specified percentage of the largest drawdowns over an investment horizon and includes maximum and average drawdowns as particular cases the necessary optimality conditions for a portfolio optimization problem with cdar yield the capital asset pricing model capm stated in both single and multiple sample path settings the drawdown beta in the capm has a simple interpretation and is evaluated for hedge fund indices from the hfrx database in the single sample path setting drawdown alpha is introduced similarly to the alpha in the classical capm and is evaluated for the same hedge fund indices both drawdown beta and drawdown alpha are used to prioritize hedge fund strategies and to identify instruments for hedging against market drawdowns

equilibrium with investors using a diversity of deviation measures abstract it has been argued that investors who optimize their portfolios with attention paid only to mean and standard deviation will all end up choosing some multiple of a certain master fund portfolio justification for the capital asset pricing model of classical portfolio theory which relates individual assets to such a master fund has come from this direction in particular attempts have been made to provide solid mathematical support by showing that the imputed behavior of investors is a consequence of price equilibrium in a market in which assets are traded subject to budget constraints and optimization is carried out with respect to utility functions that depend only on mean and standard deviation in recent years reliance on standard deviation has come under increasing criticism because of inconsistencies in its effect on portfolio preferences one response has been to introduce generalized measures of deviation which lead to alternative master funds the market implications of such extensions of theory have hitherto been unclear but in this paper the existence of equilibrium is established in circumstances where nonstandard deviations are admitted equilibrium is guaranteed even when different investors use different measures of deviation and thereby end up with portfolios scaled from different master funds whether they employ the same measure or not they may impose caps on deviation which likewise may be different

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

an international study of tax effects on government bonds it is shown that coupon bonds alone are not sufficient to span time dated claims on ordinary income capital gains and non taxable wealth in an incomplete bond market where the pure dated claims are not spanned by existing bonds marginal rates of substitution between present consumption and pure dated claims on ordinary income capital gains income and non taxable wealth respectively can differ across bondholders however the relative pricing of coupon bonds in each of these countries is shown to be consistent with the tax status of the major non tax exempt holders of government debt

capital asset prices with and without negative holdings prize lecture to the memory of alfred nobel december 7 1990 this abstract was borrowed from another version of this item

term structure multiplicity and clientele in markets with transactions costs and taxes the authors investigate term structure with realistic transactions costs and taxes its properties are derived from a certain no arbitrage condition via duality theory in convex programming transactions costs imply an infinite multiplicity of term structures a simple example with realistic transactions costs shows that this multiplicity can induce a valuation range of over 277 basis points transactions costs also allow equilibrium without short sale restrictions the authors find the minimum transactions costs that prevent arbitrage in addition the exact conditions for weak clientele in which investors will not buy some bonds and may not sell any that they already hold are established most research on the pricing of riskless bonds hereafter bonds uses a noarbitrage model equilibrium pricing is based on the assumption that there is no buy and hold investment strategy that provides riskless arbitrage profit however most of these studies ignore transactions costs 2 the clientele model hereafter ss developed by stephen schaefer 19 adopts a no arbitrage assumption na equivalent to the existence of a valuation operator this operator is a vector of discount factors known as the term structure ss shows that na implies the existence of a tax bracket specific term structure that ensures that the bonds after tax present values do not exceed their prices ss also shows that in markets with spanning positive term structures consistent with na will not exist for some brackets see his example in subsection iva below investors in such brackets would have arbitrage opportunities to resolve this na violation and make equilibrium feasible ss assumes a prohibition on shorting this implies clientele effects in the usual sense i e investors in some brackets hold some but not all bonds there may be however a bracket in which investors hold positive amounts of all bonds this would be a

arbitrage and martingales with taxation this paper extends the martingale analysis of no arbitrage pricing to worlds with taxation the absence of arbitrage is shown to imply the existence of different shadow prices for income streams that are subject to differing tax treatments for example no arbitrage implies the existence of different martingale measures for capita l gains and for ordinary income when they are differentially taxed andfor item s such as depreciation expenses that influence only after tax cash flows the analysis is applied to several topics in finance including the debt equity decision tax options and the taxation of dividends and pensions copyright 1987 by university of chicago press

portfolio investment with the exact tax basis via nonlinear programming computing the optimal portfolio policy of an investor facing capital gains tax is a challenging problem because the tax to be paid depends on the price at which the security was purchased the tax basis the optimal policy is path dependent and the size of the problem grows exponentially with the number of time periods dammon et al 2001 2002 2004 garlappi et al 2001 and gallmeyer et al 2001 address this problem byapproximating the exact tax basis by the weighted average purchase price our contribution is threefold first we show that the structure of the problem has several attractive features that can be exploited to determine the optimal portfolio policy using theexact tax basis via nonlinear programming second we characterize the optimal portfolio policy in the presence of capital gains tax when using theexact tax basis third we show that the certainty equivalent loss from using the average tax basis instead of the exact basis is very small it is typically less than 1 for problems with up to 10 periods and this result is robust to the choice of parameter values and to the presence of transaction costs dividends intermediate consumption labor income tax reset provision at death and wash sale constraints

miller s irrelevance mechanism a note this note attempts to clarify miller s 12 capital structure irrelevance mechanism using a geometric edgeworth box diagrams presentation such an exercise is useful because miller s proposition is founded on analytically complex equilibrium arguments that tend to mask the intuition and logic behind his result since miller s original discussion unnecessarily assumed a zero tax on equity income and since miller did not prove his clientele effects rigorously we also focus our attention on the deangelo and masulis 8 9 henceforth d m generalization of the miller model the d m framework is also important because it assumes a proportional tax code as we shall see whether the tax code is proportional or progressive is an important factor in understanding miller s proposition

existence of equivalent martingale measures in finite dimensional securities markets abstract given the information structure and the number of securities we characterize the set of all price dividend systems for which there exist a dynamic portfolio with strictly positive value through time and a strictly positive probability q such that expressing prices and dividends in units of such portfolio every gain process is a q martingale we also weaken our characterization by showing that the existence of a trading strategy with strictly positive terminal payoffs only is generically sufficient for the existence of an equivalent martingale measure finally an example shows that our results robustely extend the current literature on the topic journal of economic literature classification numbers d52 g10 g12

taxation of asset income in the presence of a world securities market abstract this paper examines a capm model of world security prices in which governments recognize their ability to influence international security prices via their tax treatment of foreign and domestic investors in this model governments have the incentive to set tax rates such that investors tend to specialize in domestic securities and to restrict net capital flows between countries each country does this to increase the utility of domestic residents taking as given the tax policies of other governments but the net outcome is a reduction in world efficiency and likely a reduction in the utility of all investors

impact on real and reactive power pricing in open power market using unified power flow controller transmission pricing is an important issue in view of increased deregulation a nonlinear optimization problem has been formulated to maximize the social welfare in the open power market using a unified power flow controller upfc in this paper with a static point of view congestion management installation of upfc requires a two step approach first the proper location of these devices in the network must be ascertained and then the settings of its control parameters optimized for the required objective nodal spot prices for both real and reactive powers have been computed using optimal power flow solutions and the impact of upfc on the spot pricing have been studied the effectiveness of the proposed methods is demonstrated on a test system

tax management and investment strategies of property liability insurers abstract the tax reform act tra of 1986 reduced the incentives for institutional investors to participate in the tax exempt bond market this paper develops a model of profit maximization incorporating the tra provisions applicable to property liability pl insurers the theory predicts that pl insurers will use underwriting losses to shelter taxable investment income and invest the balance of their portfolios in tax favored securities our empirical evidence reveals that insurers continued to invest in tax exempts following the tra suggesting that implicit tax rates are low enough to attract insurers into the long term tax exempt market however insurers reduced the proportions of income derived from tax exempt interest and dividends following the tra

combined pool bilateral dispatch i performance of trading strategies this three paper series deals with the dispatch of power networks under mixed pool bilateral trading the major questions examined are i to what degree does the relative level of pool versus bilateral trading influence performance in terms of individual power levels costs prices revenues and expenditures ii what is the comparative performance of mixed trading with firm and nonfirm bilateral contracts under various curtailment strategies and iii is the revenue derived from the pool and bilateral trading consistent with the corresponding unbundled costs the above issues are sequentially addressed in each of the three parts the eventual goal of these results is to help generator and load serving entities choose appropriate relative levels of pool versus bilateral trades while considering risk economic performance as well as physical constraints this paper proposes a one step optimal power flow model that dispatches the pool in combination with the privately negotiated bilateral contracts while minimizing cost and accounting for both losses and congestion in part i notions of pool bilateral demand and generation as well as a number of technical and economic performance measures for each competing entity are defined this dissection of total and individual financial measures according to pool or bilateral trading allows the market participant to evaluate the profitability of each component of its chosen pool bilateral mix a number of simulation results illustrate the effect of varying the relative levels of pool bilateral trading on the values of individual performance measures

optimal consumption and portfolio policies when asset prices follow a diffusion process abstract we consider a consumption portfolio problem in continuous time under uncertainty a martingale technique is employed to characterize optimal consumption portfolio policies when there exist nonnegativity constraints on consumption and on final wealth we also provide a way to compute and verify optimal policies our verification theorem for optimal policies involves a linear partial differential equation unlike the nonlinear partial differential equation of dynamic programming the relationship between our approach and dynamic programming is discussed we demonstrate our technique by explicitly computing optimal policies in a series of examples in particular we solve the optimal consumption portfolio problem for hyperbolic absolute risk aversion utility functions when the asset prices follow a geometric brownian motion the optimal policies in this case are no longer linear when nonnegativity constraints on consumption and on final wealth are included by these examples one can see that our approach is much easier than the dynamic programming approach

optimal stock trading with personal taxes implications for prices and the abnormal january returns abstract the tax law confers upon the investor a timing option to realize capital losses and defer capital gains with the tax rate on long term gains and losses being about half the short term rate the law provides a second timing option to realize losses short term and gains long term if at all our theory and simulation over the 1962 1977 period establish that taxable investors should realize long term gains in high variance stocks and repurchase stock in order to realize potential future losses short term tax trading does not explain the small firm anomaly but predicts a seasonal pattern in trading volume which maps into a seasonal pattern in stock prices the january anomaly only if investors are irrational or ignorant of the price seasonality

intertemporal asset pricing with heterogeneous beliefs abstract we examine the behaviour of the interest rate asset prices and asset holdings in an economy with heterogeneous rationally updated beliefs about the expected rate of production growth the equilibrium interest rate is a weighted average of the interest rates that would prevail in economies populated by homogeneous agents with the beliefs of the respective agents in the heterogeneous model the weights are given by the fractions of total wealth held financial innovation affects the dynamics of allocations and prices but preserves the aggregate output process and the structure of equilibrium asset prices also display the wealth weighted average characterization journal of economic literature classification numbers c60 d52 d91 g12

municipal debt and marginal tax rates is there a tax premium in asset prices we study the marginal tax rate incorporated into short term municipal rates using municipal swap market data using an affine model we identify the marginal tax rate and the credit liquidity spread in 1 week tax exempt rates as well as their associated risk premia the marginal tax rate averages 38 0 and is related to stock bond and commodity returns the tax risk premium is negative consistent with the strong countercyclical nature of after tax fixed income cash flows these results demonstrate that tax risk is a systematic asset pricing factor and help resolve the muni bond puzzle

incomplete preferences and equilibrium in contingent markets this paper shows that betting or speculative trading between agents with incomplete preferences is likely to occur if agents have access to convex choice sets this contrasts sharply with endowment economy models where preference incompleteness often hinders betting speculative trading or mutually beneficial insurance arrangements our results imply that decision makers with identical tastes and identical feasible sets will potentially gain from speculative trade for generic status quo allocations we also develop a framework for endogenizing the status quo allocations of decision makers that are treated exogenously in the existing literature finally we provide a tractable differential representation of status quo allocations equilibria and conditions where speculative trade may or may not emerge

persistence of regulatory innovation mmmfs and financial intermediaries abstract regulation induced innovation may persist in the deregulated environment if the fixed costs of innovation are too high to be incurred without the incentives created by binding regulation the example of money market mutual funds mmmfs illustrates the dynamics leading to lasting change the effects of mmmfs entry on thrift and commercial bank deposit shares are examined mmmfs are found to substitute for thrift but not commercial bank deposits mmmfs reduced thrift deposit share deregulation did not restore lost share and substitutability persisted into the post regulation environment with increases in gnp mmmfs now acquire share that would conceivably have gone to banking institutions

a note on capital asset pricing and heterogeneous taxes abstract in this paper we present a stylized model where we show how asset prices i e required expected rates of returns may be characterized in a world with heterogeneous asset taxes within a simple capm like framework we derive an after tax beta equal to the pre tax beta multiplied by a non obvious asset specific tax adjustment we further show in what sense the security market line here can be replaced by a security market fan well known capm relations are obtained as special cases and policy implications are analyzed

tax arbitrage and the existence of equilibrium prices for financial assets in models where both investors and securities are subject to differential taxation there may be no set of prices that rule out infinite gains to trade or tax arbitrage this paper characterizes the joint restrictions on financial asset returns and investors tax schedules that preclude tax arbitrage in the absence of short sale constraints the authors show that if there exists any configuration of marginal tax rates on investors tax schedules that rule out infinite gains to trade then no tax arbitrage prices will exist they also show that the existence of no tax arbitrage prices ensures the existence of equilibrium prices the effects of differential taxation on the equilibrium prices of financial assets have attracted much attention from financial economists in recent years otherwise identical securities that contribute to taxable income to different degrees will in general be valued differently by taxable investors as a result tax considerations have been useful in helping explain the effect of dividend yield on stock returns the effect of coupon levels and term to maturity on bond prices 2 the timing of investors portfolio transactions 3 and the observed capital structures of firms 4 while a rich set of observed behaviors can be better understood by reference to differential taxation there are well known difflculties in dealing with taxes in a general equilibrium setting to clear markets relative prices must reflect the marginal rates of substitution of all agents simultaneously when tax rates differ across investors however this condition can be impossible to achieve to illustrate consider a world of perfect certainty with two assets a tax exempt municipal bond and a taxable government bond to equate marginal rates of substitution the rate of return on the government bond rg must equal that on the municipal rm grossed up by one minus the investor s marginal tax rate ti that is rg rm 1 ti if there are investors in more than one tax bracket this condition will obviously be impossible to satisfy for all of them simultaneously both authors from graduate school of industrial administration carnegie mellon university we wish to thank scott richard steven spear and an anonymous referee for helping us sort through the issues considered here seminar participants at columbia wharton the johnson symposium on asset pricing at the university of wisconsin madison and the 1986 western finance association meeting also provided valuable comments we are also grateful for the financial support provided by the center for public policy research carnegie mellon university all errors are our own responsibility

the optimal trading and pricing of securities with asymmetric capital gains taxes and transaction costs this article explores the optimal trading and pricing of taxable securities with asymmetric capital gains taxes and transaction costs in the long term region investors realize all gains below some critical cutoff level which we derive analytically in the short term region investors defer all gains and depending upon the time remaining in the short term region may also defer small losses contrary to common intuition deferral of short term losses can be optimal even without transaction costs the value of tax timing is considerably bigger under the optimal trading strategy than under alternative strategies previously analyzed the impact of offset rules is also explored article published by oxford university press on behalf of the society for financial studies in its journal the review of financial studies

optimal portfolios when volatility can jump abstract we consider an asset allocation problem in a continuous time model with stochastic volatility and jumps in both the asset price and its volatility first we derive the optimal portfolio for an investor with constant relative risk aversion the demand for jump risk includes a hedging component which is not present in models without volatility jumps we further show that the introduction of derivative contracts can have substantial economic value we also analyze the distribution of terminal wealth for an investor who uses the wrong model either by ignoring volatility jumps or by falsely including such jumps or who is subject to estimation risk whenever a model different from the true one is used the terminal wealth distribution exhibits fatter tails and in some cases significant default risk

taxation portfolio choice and debt equity ratios a general equilibrium model this paper explores the portfolio behavior of investors differing with respect to both tax rates and risk aversion emphasizing the role of constraints on individual and firm behavior in ensuring the existence of and characterizing portfolio equilibrium under certain conditions on the securities available in the market which also are necessary for shareholders to be unanimous in supporting firm value maximization investors will be segmented by tax rate into two groups one specialized in equity and the other in debt though the relative wealths of the two groups determine the aggregate debt equity ratio each firm will be indifferent to its financial policy

a reexamination of the value of tax options this article reexamines the value of tax trading when the tax rate on long term realizations is less than that on short term realizations in particular the value of the option to realize long term capital gains and repurchase stock in order to increase one s tax basis and restart the option to realizefuture losses short term is examined empirically our estimate of the incremental value of restarting which is based on the results of simulations of several alternative tax trading policies over a large number of independent return sequences is generally much smaller than that reported by constantinides 1984 the incremental value of restarting is shown to depend critically on the particular pattern of realized returns and the assumed tax treatment of unrealized capital gains at the end of the simulation period the effects of stockprice volatility transaction costs portfolio offset rules and realization cutoff levels on the value of tax trading are also investigated

limiting losses may be injurious to your wealth abstract theory tells us that if return distributions are independent over time an expected utility maximizing logarithmic utility investor will almost surely accumulate the most long run wealth this paper examines the robustness of the result specifically it examines the expected and unexpected long run and short run consequences of imposing value at risk and other loss constraints on power utility investors with a numerical example and empirically in an asset allocation setting covering the 1934 2008 period in addition it examines the expected and unexpected long run consequences of imposing conditional value at risk constraints on power utility and prospect theory kinked linear utility investors

diversification consistent data envelopment analysis with general deviation measures abstract we propose new efficiency tests which are based on traditional dea models and take into account portfolio diversification the goal is to identify the investment opportunities that perform well without specifying our attitude to risk we use general deviation measures as the inputs and return measures as the outputs we discuss the choice of the set of investment opportunities including portfolios with limited number of assets we compare the optimal values efficiency scores of all proposed tests leading to the relations between the sets of efficient opportunities strength of the tests is then discussed we test the efficiency of 25 world financial indices using new dea models with cvar deviation measures

combined pool bilateral dispatch part ii curtailment of firm and nonfirm contracts this paper deals with the dispatch of power networks under mixed pool bilateral trading the major questions that are examined are the following 1 to what degree does the relative level of pool versus bilateral trading influence performance in terms of individual power levels costs prices and revenues 2 what is the comparative performance of mixed trading with firm and nonfirm bilateral contracts under various curtailment strategies 3 is the revenue derived from the pool and bilateral trading consistent with the corresponding unbundled costs the above questions are sequentially addressed in separate parts of this three part paper the eventual goal of these results is to help generator and load serving entities choose appropriate relative levels of pool versus bilateral trades while considering risk economic performance and physical constraints in part ii two types of bilateral contracts firm and nonfirm are introduced together with their respective curtailment and noncurtailment bids the optimal power flow problem from part i is now modified to accommodate this new type of operation technical and economical performance measures defined in part i namely generation revenues from bilateral and pool sales pool demand payments plus generation and load expenditures to cover transmission loss and congestion management attributed to bilateral exchanges are also used here together with revenues from contract curtailment and expenditures due to noncurtailment bidding simulation results illustrate the effects of firm and nonfirm contracts and their bidding strategies on the relative levels of pool bilateral trading as well as on economic performance of market participants

congestion influence on bidding strategies in an electricity market much of the research on bidding strategies in an electricity market has focused on idealized situations where participants have limited market power and the transmission system is not constrained yet congestion may act to effectively give a bidder market power and consequently the ability to influence the market clearing price in such a noncompetitive situation the bidding strategies of market participants will change in this paper the electrical power market is modeled as an oligopoly market and the cournot quantity model is applied to the bidding strategy problem the bidding process with congestion management is modeled as a three level optimization problem a statistical methodology is then proposed as a solution for large systems

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

market plurality and manipulation performance comparison of independent system operators in this paper the authors present three different models that represent the coordinating functions of existing independent system operators isos and discuss their advantages and disadvantages max iso is a centralized operator based on the pool model and min iso is a decentralized operator based on the bilateral model mix iso is positioned in between having multiple power exchanges or bilateral contracts the performance of the different isos is compared by the total social welfare and the vulnerability to market manipulation a numerical example is presented to compare the performance of different isos the max iso is considered to be the most efficient model theoretically but it does not necessarily provide the best market in terms of vulnerability to market manipulation

efficient trading strategies in the presence of market frictions we provide a price characterization of efficient contingent claims that is chosen by at least a rational agent in multiperiod economies with market frictions frictions include market incompleteness transaction costs short selling and borrowing costs we characterize the inefficiency cost of a trading strategy its required investment minus the largest amount necessary to obtain the same utility level and we propose a measure of portfolio performance we show that arbitrage bounds cannot be tightened based on efficiency without restricting preferences or endowments we observe common investment strategies becoming inefficient with market frictions and others rationalized by them in this article we characterize efficient contingent claims to future consumption consumption bundles in multiperiod economies with uncertainty taking a wide range of market frictions into account 1 such as dynamic market

arbitrage short sales and financial innovation the authors describe a model of general equilibrium with incomplete markets in which firms can innovate by issuing arbitrary costly securities when short sales are prohibited firms behave competitively and equilibrium is efficient when short sales are allowed these classical properties may fail if unlimited short sales are allowed imperfect competition may persist even when the number of potential innovators is large if limited short sales are allowed perfect competition may obtain in the limit but equilibrium can be inefficient because of the presence of an externality the private benefits of innovation for firms differ from the social benefits copyright 1991 by the econometric society

put call parity and market frictions abstract we extend the fundamental theorem of finance and the pricing rule representation theorem to the case in which market frictions are taken into account but the put call parity is still assumed to hold in turn we obtain a representation of the pricing rule as a discounted expectation with respect to a nonadditive risk neutral probability

arbitrage pricing transaction costs and taxation of capital gains abstract this paper examines one of the few cases of seemingly redundant securities sets of three government bonds with the same maturity date within the bounds on relative bond prices established by tax exempt investors in a market with proportional transaction costs the taxation of capital gains on the basis of realization has a significant impact on relative prices the empirical evidence supports the tax option effect discussed by constantinides and ingersoll but does not generally support the segmented tax clientele equilibrium discussed by schaefer

capital structure investment and fire sales we study a dynamic general equilibrium model in which firms choose their investment level and capital structure trading off the tax advantages of debt against the risk of costly default bankruptcy costs are endogenous as bankrupt firms are forced to liquidate their assets resulting in a fire sale if the market is illiquid when the corporate income tax rate is positive firms have a unique optimal capital structure in equilibrium firms default with positive probability and their assets are liquidated at fire sale prices the equilibrium features underinvestment and is constrained inefficient in particular there is too little debt and default

valuation of risky assets in arbitrage free economies with frictions this paper derives a framework for arbitrage models in markets with frictions it generalizes the existence of a valuation operator to such markets as in perfect markets the valuation operator is a linear operator and its existence is implied by the no arbitrage condition in imperfect markets the valuation operator is individual specific and depends on the agent s position in the market the methodology employed in the paper is duality in convex programming

tax clienteles and optimal capital structure under uncertainty this article demonstrates that investors heterogeneous tax status implies that they value bonds differently at the margin due to asymmetric personal taxes high risk bonds generate a higher amount of taxable income than low risk bonds and are therefore held by investors in low tax brackets in such a setting firms can increase their value by choosing a capital structure that attracts a particular bondholder clientele the author analyzes how bondholder clienteles change as the uncertainty about a bond s final payoff is resolved over time and shows how tax clientele effects influence firms capital structure decisions copyright 1990 by the university of chicago

term structure of interest rates and implied market frictions the min max approach it is often assumed that financial markets are frictionless bond markets are illiquid and bond prices are observed with errors the magnitude of these errors leads to violation of no arbitrage conditions and consequently prevents researchers from obtaining an estimate of the term structure ts of interest rates researchers have had to settle for a second best estimate of the ts e g obtained via regression at a cost of an economically unrealistic assumption of symmetric market frictions the true shape of market frictions however is not known and generally is a highly complex issue a no arbitrage based methodology that avoids making detrimental assumptions is developed here it facilitates empirical investigation of the shape of the market frictions and of the ts that are simultaneously imputed from market data assuming efficient market frictions that minimize the maximum net arbitrage the empirical investigation performed in the canadian and u s markets shows that in both markets the frictions are asymmetric and the estimates of the ts produced via regression and our methodology significantly differ

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

the safety first expected utility model experimental evidence and economic implications abstract roy s roy a 1952 safety first and the holding of assets econometrica 20 3 431 449 safety first criterion advocates the minimization of the probability of outcomes below a certain disaster level this paper examines safety first theoretically and experimentally we find that safety first plays a crucial role in decision making inducing choices that cannot be explained by and even contradict risk aversion prospect theory and loss aversion in general yet safety first alone cannot explain individual choice therefore we propose an expected utility safety first eu sf model where decisions are made based on a weighted average of the safety first criterion and standard expected utility maximization we experimentally estimate these relative weights and discuss their economic implications