Price impact,strategic interaction and portfolio choice

This paper studies the portfolio choice of two large investors who act strategically because their trading affects interest rates. Each investor chooses her optimal portfolio conditional on the portfolio of the opponent. Equilibrium portfolios and their performance depend on the investor’s characteristics (risk aversion and return impact) and on the characteristics of the opponent (risk aversion and return impact). Depending on the interplay among these characteristics, strategic interaction can (i) increase or decrease risk taking incentives, as compared to the Merton-style portfolio, (ii) induce the more risk-averse investor to invest relatively more in the risky asset and (iii) change the role of inflation-linked bonds from hedging instrument to borrowing opportunity.     

Margin trade,short sales and financial stability

We model how leveraged trading activities constrained by dynamic funding availability affect financial stability. In the market, customers trade based on the fundamental value of the risky asset and make full payment for their transactions, while speculators take trading position based on margin, which is constantly adjusted by the financier, the fund provider, according to the price volatility. As a result of equilibrium price discontinuity triggered by dynamic margin requirements, trivial shocks to external supply, wealth or fundamental value can be transmitted into asset price crashes or jumps. We find that tightening margin requirements improves (mitigates) the market liquidity in the bull (bear) market, and that imposing short sale constraints helps prevent the price from falling further when the asset is sufficiently under-priced and accelerate price collapse when the asset is over-priced.

     

Selective Trading of Available-for-Sale Securities: Evidence from U.S. Commercial Banks

This paper examines the selective trading of available-for-sale (AFS) securities by U.S. banks after the implementation of fair value accounting under Statement of Financial Accounting Standards No. 115, Accounting Standards Codification Topic 320. Our findings suggest firms still engage in earnings management through selective selling of AFS securities despite the mandatory disclosure of unrealized security holding gains and losses in their financial statements. Such activities do not appear to be driven by the lack of reliability of the fair value measure. Instead, the degree of earnings management varies significantly with the reporting format of unrealized AFS security holding gains and losses. We find evidence of earnings management among banks that choose to report unrealized holding gains and losses in the statement of shareholders’ equity. By contrast, we find no such evidence among banks disclosing unrealized holding gains and losses in the income statement.     

The consumption–investment decision of a prospect theory household: A two-period model

This study extends the literature on portfolio choice under prospect theory preferences by introducing a two-period life cycle model, where the sufficiently loss averse household decides on optimal consumption and investment in a portfolio with one risk-free and one risky asset. The optimal solution depends primarily on whether the household’s present value of the consumption reference levels is below, equal to, or above the present value of its endowment income. Reference levels below the endowment income are associated with the self-enhancement motive. In this case, the household avoids relative losses in consumption in any present or future state of nature (good or bad). As a result the degree of loss aversion does not directly affect optimal consumption and risk taking activity. Reference levels equal to the endowment income are associated with the belonging motive. An example would be a household comparing to others that belong to the same social class. In this case the household’s optimal consumption is the reference consumption and the household will not invest in the risky asset. Finally, reference levels above the endowment income are associated with the self-improvement motive (or high aspirations). For such high reference levels, households cannot avoid experiencing a relative loss in consumption, either now or in the future. As a result, loss aversion directly affects consumption and risky investment.     

Do Investors Pay Sufficient Attention to Banks’ Unrealized Gains and Losses on Available-for-sale Securities?

Abstract

Unrealized gains and losses on available-for-sale securities (AFSGL) are included in Other Comprehensive Income (OCI) and directly affect shareholders’ equity but are not included in earnings. We investigate whether unrealized AFSGL help predict future earnings and whether analysts and investors incorporate the information conveyed by unrealized AFSGL in a timely manner. We conduct our investigation on a sample of banks because unrealized AFSGL are material in the banking industry. First, we show that unrealized AFSGL are material and help in predicting next period realized AFSGL and future earnings change. Second, we document that financial analysts are slow to react to unrealized AFSGL and update their forecasts after AFSGL are realized in earnings. Third, we find that investors are also slow to react to unrealized AFSGL and do so only after AFSGL are included (realized) in earnings and after financial analysts update their forecasts. We document an annual difference of 5% in future abnormal returns between banks in the top and bottom quintiles of past unrealized AFSGL. A zero-cost trading strategy that relies on public information about unrealized AFSGL generates a sizeable monthly alpha that ranges between 1.8% and 1.9%.     

Portfolio choice in the model of expected utility with a safety-first component

Decisions in Economics and Finance - The standard problem of portfolio choice between one risky and one riskless asset is analyzed in the model of expected utility with a safety-first component...     

Asset price and wealth dynamics in a financial market with heterogeneous agents

This paper considers a discrete-time model of a financial market with one risky asset and one risk-free asset, where the asset price and wealth dynamics are determined by the interaction of two groups of agents, fundamentalists and chartists. In each period each group allocates its wealth between the risky asset and the safe asset according to myopic expected utility maximization, but the two groups have heterogeneous beliefs about the price change over the next period: the chartists are trend extrapolators, while the fundamentalists expect that the price will return to the fundamental. We assume that investors’ optimal demand for the risky asset depends on wealth, as a result of CRRA utility. A market maker is assumed to adjust the market price at the end of each trading period, based on excess demand and on changes of the underlying reference price. The model results in a nonlinear discrete-time dynamical system, with growing price and wealth processes, but it is reduced to a stationary system in terms of asset returns and wealth shares of the two groups. It is shown that the long-run market dynamics are highly dependent on the parameters which characterize agents’ behaviour as well as on the initial condition. Moreover, for wide ranges of the parameters a (locally) stable fundamental steady state coexists with a stable ‘non-fundamental’ steady state, or with a stable closed orbit, where only chartists survive in the long run: such cases require the numerical and graphical investigation of the basins of attraction. Other dynamic scenarios include periodic orbits and more complex attractors, where in general both types of agents survive in the long run, with time-varying wealth fractions.     

Homeownership and mixed-asset portfolio allocations

Homeownership represents both a consumption and an investment decision for individuals. Considering the investment benefits of the home, we estimate the total returns and risk associated with the investment in single-family homes. Then, using a mean–variance utility function, we consider the impact of homeownership and mortgage loan financing on the optimal asset allocation decisions of individuals and contrast this with advice that does not include the home as part of the portfolio. While optimal portfolio weights are dependant upon both the degree of risk aversion of the individual investor and the relative importance of the home in the overall net worth picture, we show that, in general, the higher the home-to-net worth ratio, the higher the optimal portfolio allocation to stock. For most investors, including the home in the optimization decision leads to higher allocations to risky stock than suggested by traditional advice that ignores the home.     

Adaptive market hypothesis: The story of the stock markets and COVID-19 pandemic

Since the level of markets’ information efficiency is key to profiteering by strategic players, Shocks; such as the COVID-19 pandemic, can play a role in the nature of markets’ information efficiency. The martingale difference and conditional heteroscedasticity tests are used to evaluate the Adaptive form of market efficiency for four (4) major stock market indexes in the top four affected economies during the COVID-19 pandemic (USA, Brazil, India, and Russia). Generally, based on the martingale difference spectral test, there is no evidence of a substantial change in the levels of market efficiency for the US and Brazilian stock markets in the short, medium, and long term. However, in the long term, the Indian stock markets became more information inefficient after the coronavirus outbreak while the Russian stock markets become more information efficient. Intuitively, these affect the forecastability and predictability of these markets’ prices and/or returns. Thereby, informing the strategic and trading actions of stock investors (including arbitrageurs) towards profit optimization, portfolio asset selection, portfolio asset adjustment, etc. Similar policy implications are further discussed.     

Arbitrage concepts under trading restrictions in discrete-time financial markets

In a discrete-time setting, we study arbitrage concepts in the presence of convex trading constraints. We show that solvability of portfolio optimization problems is equivalent to absence of arbitrage of the first kind, a condition weaker than classical absence of arbitrage opportunities. We center our analysis on this characterization of market viability and derive versions of the fundamental theorems of asset pricing based on portfolio optimization arguments. By considering specifically a discrete-time setup, we simplify existing results and proofs that rely on semimartingale theory, thus allowing for a clear understanding of the foundational economic concepts involved. We exemplify these concepts, as well as some unexpected situations, in the context of one-period factor models with arbitrage opportunities under borrowing constraints.     

Reaching nirvana with a defaultable asset?

We study the optimal dynamic portfolio exposure to predictable default risk, taking inspiration from the search for yield by means of defaultable assets observed before the 2007–2008 crisis and in its aftermath. Under no arbitrage, default risk is compensated by an ‘yield pickup’ that can strongly attract aggressive investors via an investment-horizon effect in their optimal non-myopic portfolios. We show it by stating the optimal dynamic portfolio problem of Kim and Omberg (Rev Financ Stud 9:141–161, 1996) for a defaultable risky asset and by rigorously proving the existence of nirvana-type solutions. We achieve such a contribution to the portfolio optimization literature by means of a careful, closed-form-yielding adaptation to our defaultable asset setting of the general convex duality approach of Kramkov and Schachermayer (Ann Appl Probab 9(3):904–950, 1999; Ann Appl Probab 13(4):1504–1516, 2003).     

Mean–variance econometric analysis of household portfolios

We investigate households' portfolio choice using a microeconometric approach derived from mean–variance optimization. We assume that households have heterogeneous expectations on the distribution of excess returns and that they cannot take short positions in risky assets. Assuming two such assets, we derive an explicit solution of the model characterized by four possible portfolio regimes, which are analyzed using two structural probit and tobit specifications with three latent state variables. Both specifications are estimated by weighted maximum likelihood on a cross‐section of US households drawn from the 2004 SCF. The tobit specification is simulated in order to evaluate the regressors' effects on regime probabilities and asset demands. We also assess to what extent the predicted state variables are consistent with the self‐reported expected returns and risk aversion elicited from the SCF questionnaire. Copyright © 2009 John Wiley & Sons, Ltd.     

Dynamic portfolio choice under ambiguity and regime switching mean returns

I examine a continuous-time intertemporal consumption and portfolio choice problem under ambiguity, where expected returns of a risky asset follow a hidden Markov chain. Investors with Chen and Epstein's (2002) recursive multiple priors utility possess a set of priors for unobservable investment opportunities. The optimal consumption and portfolio policies are explicitly characterized in terms of the Malliavin derivatives and stochastic integrals. When the model is calibrated to U.S. stock market data, I find that continuous Bayesian revisions under incomplete information generate ambiguity-driven hedging demands that mitigate intertemporal hedging demands. In addition, ambiguity aversion magnifies the importance of hedging demands in the optimal portfolio policies. Out-of-sample experiments demonstrate the economic importance of accounting for ambiguity.     

Gradual information diffusion and contrarian strategies

Various rational and behavioral models have been proposed to explain contrarian portfolio returns. In this article, I test the gradual information diffusion model of Hong and Stein [Hong, H., & Stein J. C. (1999). A unified theory of underreaction, momentum trading, and overreaction in asset markets. Journal of Finance, 54, 2143–2184]. Specifically, I study contrarian strategies based on past long-term returns and fundamental value-to-price ratios. Using ex post returns as a proxy for expected returns and size-controlled analyst coverage as a proxy for the rate of information diffusion, I show that contrarian portfolio returns decline monotonically with increasing rates of information diffusion. These results are consistent with the predictions of the Hong and Stein model. In addition, I show that analyst coverage is more important among glamour than value stocks, supporting the view that investors are more prone to decision biases when it comes to pricing hard-to-value glamour stocks for which information is relatively more ambiguous.     

Effects of time horizon and asset condition on the profitability of technical trading rules

In much of the literature, the debate over technical trading strategies has centered around the question of whether an actively managed portfolio, controlled by a technical indicator, can outperform a passively managed portfolio. Typically, the time horizon is considered to be years. Additionally, the trader is assumed to use a technical trading strategy that is independent of asset conditions. These assumptions may not correspond well with reality. Traders often have much shorter time horizons and may switch between rebalancing or trading strategies on the basis of perceived shifts in market condition. This paper presents a study of the profitability of technical trading rules as a function of asset state or condition. Several common technical trading strategies were run on 296 stocks over a 15 year period. Strategies were run with 1 month rolling time horizons, significantly shorter than those used in similar studies in the literature. Stocks were segmented based on volatility and volume, which allowed for the examination of a strategy’s performance in different asset conditions. Several strategies were demonstrated to have consistently better risk-to-reward ratios under specific asset conditions and short time horizons. This finding helps to explain why some practitioners implement technical trading strategies.     

Minimum-cost portfolio insurance

Minimum-cost portfolio insurance is an investment strategy that enables an investor to avoid losses while still capturing gains of a payoff of a portfolio at minimum cost. If derivative markets are complete, then holding a put option in conjunction with the reference portfolio provides minimum-cost insurance at arbitrary arbitrage-free security prices. We derive a characterization of incomplete derivative markets in which the minimum-cost portfolio insurance is independent of arbitrage-free security prices. Our characterization relies on the theory of lattice-subspaces. We establish that a necessary and sufficient condition for price-independent minimum-cost portfolio insurance is that the asset span is a lattice-subspace of the space of contingent claims. If the asset span is a lattice-subspace, then the minimum-cost portfolio insurance can be easily calculated as a portfolio that replicates the targeted payoff in a subset of states which is the same for every reference portfolio.     

Collective rationality and functional wisdom of the crowd in far-from-rational institutional investors

The average portfolio structure of institutional investors is shown to reproduce the structure which optimally accounts for transaction costs when investment constraints are weak. Strikingly, this result emerges even though these investors are not aware of the existence of such law and despite the fact that their aims and tools are very heterogeneous. This extends the so-called wisdom of the crowd to much more complex situations in two important ways. First, wisdom of the crowd also holds for whole functions instead of a point-wise estimates. Second, this shows that in socio-economic systems, the optimal individual choice may only be found when the diversity of individual decisions is averaged out. Thus, rationality at a collective level does not need nearly rational individuals with well-aligned incentives. Finally we discuss the importance of accounting for constraints when assessing the presence of wisdom of the crowd.

     

Equilibrium and arbitrage in incomplete asset markets with fixed prices

At arbitrary prices of commodities and assets, fix-price equilibria exist under weak assumptions: endowments need not satisfy an interiority condition, utility functions need only satisfy a very weak monotonicity requirement, and the asset return matrix allows for redundant assets. Prices of assets may permit arbitrage. At equilibrium, though restricted through endogenously determined trading constraints, arbitrage possibilities may persist; in an example, an individual holds an arbitrage portfolio.     

The number of securities giving the maximum return in the presence of transaction costs

An essential element of any realistic investment portfolio selection is the consideration of transaction costs. Our purpose, in this paper, is to determine the maximum return and the corresponding number of securities to buy giving such return, whenever practical constraints features related to budget, buy-in thresholds, and transaction costs are taken into consideration. Dealing with the portfolio selection and optimization problem in the point of view of individual investors, we will arrive to get an analytic result, leading to a new and simple alternative solution to heuristic algorithms. Moreover, this result can be considered as another approach to integer optimization.     

Wavelet decomposition of heterogeneous investment horizon

Building on the assumptions that investors are heterogeneous and that not all of them are fully rational, the market for trading any financial instrument can be separated into several segments, each associated with a different investment horizon. Thus, the expected return on an asset for each horizon maintains a different functional relationship with an expected market return. In other words, the trading of an asset by investors with heterogeneous investment horizons results in the coexistence of multiple security market lines. This proposed theory, which offers an alternative interpretation of investment behavior from that of the capital asset pricing model (CAPM) and the efficient markets hypothesis (EMH), is verified by using the newly introduced amalgamated discrete wavelet transform.