Optimal portfolio positioning under ambiguity

This paper analyzes the optimality of financial portfolios when the investor has a utility with ambiguity aversion. It provides a general result about the optimal portfolio profile under ambiguity, in the Anscombe–Aumann framework, using the Maccheroni et al. (2006) approach which includes Gilboa and Schmeidler's (1989) multiple prior preferences and Hansen and Sargent's (2011) multiplier preferences. The paper then details the CRRA case with an ambiguity index based on relative entropy. Such findings have practical applications in structured portfolio management. Indeed, it is important to take account of uncertainty about the true values of financial parameters when determining the best portfolio profile.     

Individual Decision Making and Investor Welfare

This article analyses and quantifies the costs of suboptimal decision making for an investor with a multi-period horizon. In light of the empirical evidence that investors are too conservative and hold portfolios that are insufficiently diversified, we evaluate the costs of suboptimal equity participation both analytically and using simulation, and also estimate the costs of suboptimal diversification using simulation. We find that suboptimal leverage imposes only modest costs on the investor for reasonable parameter values. While the costs of inadequate diversification can be very high, we find that, because of the higher returns on small firms, an equally weighted portfolio of as few as five randomly chosen firms can provide the same level of expected utility as the value weighted market portfolio.
(J.E.L.: G11, G18, G23).     

Economic benefits of using realized covariance forecasts in risk-based portfolios

This article examines the economic benefit of using the realized covariance matrix forecasts, for constructing the risk-based portfolios. We use the two-scale realized covariance estimator (TSC), the jump robust two-scale realized covariance estimator (RTSC) and the realized bipower covariance estimator (BPC), to forecast the daily realized covariance matrix. Using these covariance matrix forecasts, we implement three risk-based portfolios: the global minimum variance portfolio, the equal risk contribution portfolio and the most diversified portfolio. There is evidence that the portfolio performance improves by using TSC or RTSC estimators as compared to the daily-returns-based estimator. The performance gains are robust to the choice of risk-based portfolio strategy, the degree of investor’s relative risk-aversion, the market conditions and the choice of time intervals.     

Liquidity and equity returns in Borsa Istanbul

We investigate the relationship between expected returns and liquidity measures in Borsa Istanbul. To do so, we gather a wide range of illiquidity measures that can be applied to the market. Firm-level cross-sectional regressions indicate that there is a positive relationship between various illiquidity measures and one- to six-month ahead stock returns. Findings of the article are robust after using different sample periods and controlling for well-known priced factors, such as market beta, size, book-to-market ratio and momentum. The portfolio analysis reveals that stocks that are in the highest illiquidity quintile earn 7.2%–19.2% higher risk-adjusted annual returns than those in the lowest illiquidity quintile. The illiquidity premium is stronger for small stocks and stocks with higher return volatility and it increases (decreases) during periods of extremely low (high) market returns.     

Empirical tests on the asset pricing model with liquidity risk: An unobserved components approach

The aim of this paper is to test empirically the conditional liquidity-adjusted capital asset pricing model (L-CAPM) developed by Acharya and Pedersen (2005). Accordingly, we propose to estimate the L-CAPM using unobserved components methodology, which allows us to take into account the main stylized facts characterizing liquidity. Based on a sample of firms listed on the NASDAQ, our empirical analysis reveals several findings. Firstly, we show that liquidity is time-varying and exhibits strong seasonality. Secondly, we highlight the impact of the liquidity level premium on asset prices. Thirdly, we show that the most important liquidity risk is related to the covariance between portfolio illiquidity and market returns. Fourthly, we observe a negative relationship between portfolio returns and market illiquidity. Fifthly, we find that liquidity risk and illiquidity level are not always positively correlated.     

ILLIQUIDITY COMPONENT OF CREDIT RISK – THE 2015 LAWRENCE R. KLEIN LECTURE

We provide a theoretical decomposition of bank credit risk into insolvency risk and illiquidity risk, defining illiquidity risk to be the counterfactual probability of failure due to a run when the bank would have survived in the absence of a run. We show that illiquidity risk is (i) decreasing in the “liquidity ratio”—the ratio of realizable cash on the balance sheet to short‐term liabilities; (ii) decreasing in the excess return of debt; and (iii) increasing in the solvency uncertainty—a measure of the variance of the asset portfolio.     

Forward Discount Bias: Is it Near-Rationality in the Foreign Exchange Market?*

A risk-averse US investor adjusts the shares of a portfolio of short-term nominal domestic and foreign assets to maximize expected utility. The optimal strategy is to respond immediately to all new information which arrives weekly. We develop a model to estimate the cost of optimizing less frequently and find that it is generally very small. For example, if the investor adjusts portfolio shares every three months, an average expected utility loss of 0.16 per cent p.a. is incurred. Hence, slight opportunity costs of frequent optimization may outweigh the benefits. This result may help explain forward discount bias.     

Fuzzy value-at-risk and expected shortfall for portfolios with heavy-tailed returns

This paper is concerned with linear portfolio value-at-risk (VaR) and expected shortfall (ES) computation when the portfolio risk factors are leptokurtic, imprecise and/or vague. Following Yoshida (2009), the risk factors are modeled as fuzzy random variables in order to handle both their random variability and their vagueness. We discuss and extend the Yoshida model to some non-Gaussian distributions and provide associated ES. Secondly, assuming that the risk factors' degree of imprecision changes over time, original fuzzy portfolio VaR and ES models are introduced. For a given subjectivity level fixed by the investor, these models allow the computation of a pessimistic and an optimistic estimation of the value-at-risk and of the expected shortfall. Finally, some empirical examples carried out on three portfolios constituted by some chosen French stocks, show the effectiveness of the proposed methods.     

基于后悔规避的投资组合模型及其实证分析

由于人的情感、认知等因素对投资活动有直接影响,本文在投资活动中引入人的情感因素,提出了基于后悔规避的投资者效用函数,该效用函数是期末财富和预期财富的函数。建立了存在无风险资产时的最优投资组合模型,发现基于后悔规避投资组合模型的组合前沿存在两基金分离的现象。对我国上海股票市场进行了实证分析,得到了基于后悔规避投资组合模型的组合前沿,并验证了组合前沿存在两基金分离现象的结论。     

The role of liquidity in monetary policy transmission: Evidence from Indian banks1

The role of bank liquidity in monetary policy transmission has received insufficient attention in the literature. Faced with monetary tightening, banks with more liquidity can sell off securities and protect their loan portfolios. We test this proposition using panel data for Indian banks during 2005–2020. Employing dynamic threshold panel regressions with liquid assets as the threshold variable, we show that bank lending declines with monetary policy tightening in low liquidity regimes, but not in high liquidity regimes. We also find evidence for different portfolio reallocation behaviour by banks in high versus low liquidity regimes in response to monetary policy changes.     

Local and global illiquidity effects in the Balkans frontier markets

We study market illiquidity across 11 national markets of the Balkans. In general, the EU member countries are more liquid than the nonmember countries. Turkey, however, has the most liquid market, while Serbia and Bosnia are the least liquid. Global illiquidity sourced from the US has a strong and positive impact on pricing in eight of the Balkans markets. In contrast, illiquidity transmitted from the EU impacts expected returns in only two instances, while local illiquidity is significant for just one market. Croatia and Slovenia are most susceptible to transmissions of regional illiquidity, each receiving illiquidity spillovers from four sources.     

Portfolio choice and pricing in illiquid markets

This paper studies portfolio choice and pricing in markets in which immediate trading may be impossible. It departs from the literature by removing restrictions on asset holdings, and finds that optimal positions depend significantly and naturally on liquidity: When expected future liquidity is high, agents take more extreme positions, given that they do not have to hold those positions for long when they become undesirable. Consequently, larger trades should be observed in markets with more frequent trading. Liquidity need not affect the price significantly, however, because liquidity has offsetting impacts on different agents' demands. This result highlights the importance of unrestricted portfolio choice. The paper draws parallels with the transaction-cost literature and clarifies the relationship between the price level and the realized trading frequency in this literature.     

Model uncertainty and liquidity

Extreme market outcomes are often followed by a lack of liquidity and a lack of trade. This market collapse seems particularly acute for markets where traders rely heavily on a specific empirical model such as in derivative markets like the market for mortgage backed securities or credit derivatives. Moreover, the observed behavior of traders and institutions that places a large emphasis on “worst-case scenarios” through the use of “stress testing” and “Value-at-Risk” seems different than Savage expected utility would suggest. In this paper, we capture model-uncertainty using an Epstein and Wang [Epstein, L.G., Wang, T., 1994. Intertemporal asset pricing under Knightian uncertainty. Econometrica 62, 283–322] uncertainty-averse utility function with an ambiguous underlying asset-returns distribution. To explore the connection of uncertainty with liquidity, we specify a simple market where a monopolist financial intermediary makes a market for a propriety derivative security. The market-maker chooses bid and ask prices for the derivative, then, conditional on trade in this market, chooses an optimal portfolio and consumption. We explore how uncertainty can increase the bid–ask spread and, hence, reduces liquidity. Our infinite-horizon example produces short, dramatic decreases in liquidity even though the underlying environment is stationary. We show how these liquidity crises are closely linked to the uncertainty aversion effect on the optimal portfolio. Effectively, the uncertainty aversion can, at times, limit the ability of the market-maker to hedge a position and thus reduces the desirability of trade, and hence, liquidity.     

Incentive contracts in delegated portfolio management under VaR constraint

This paper studies the incentive effect of linear performance-adjusted contracts in delegated portfolio management under a value-at-risk (VaR) constraint. It is shown that a linear performance-based contract can provide incentives for the portfolio manager to work at acquiring private information under a VaR risk constraint. The expected utility and optimal effort of a risk-averse manager are increasing functions of the return sharing ratio in the contract. However, a risk constraint causes the portfolio manager to reduce effort in gathering private information, suggesting that the VaR constraint increases the moral hazard between the investor and the manager.     

Risk Appetite,Home Bias and the Unstable Demand for Emerging Market Assets

Home bias arises when the actual portfolio of an investor consists of a smaller proportion of foreign assets than that predicted by standard portfolio theory for the observed set of risks and returns on available assets. The existence and persistence of home bias undermines the theoretical case for the efficiency of international capital markets. In this paper we use data on UK pension fund portfolios to measure home bias, and find that this is doubly acute in the case of emerging market equity—a bias against overseas assets as a whole being further magnified by a bias against emerging markets within the foreign equity class as a whole. Moreover, contrary to the conventional assumption that risk aversion is both relatively low and stable over time (canonised in neoclassical theory by the derivation of constant relative risk aversion from the utility function itself) our finding that home bias fluctuates over time suggests that risk aversion is in fact time‐variant and path‐dependent. We sketch an alternative Keynesian approach in conclusion.     

The risk-return relations: evidence from the Korean and Taiwan stock markets

This article examines the risk-return relations conditional on up and down market periods in the Korean and Taiwan stock markets. Based on statistical tests adjusted for the effects of heteroskedasticity and autocorrelation of the residuals, beta is found positively (negatively) related to realized returns in up (down) markets. However, the results are sensitive to portfolio aggregation methods. Its role as a risk measure vanishes in down markets for the two-way (beta-size and size-beta) sorted portfolios. Unsystematic risk is significantly and positively priced only in up markets and mainly for beta-sorted portfolios while total risk is correctly priced except in Taiwan during down markets. Moreover, the impact of skewness and kurtosis on realized returns is not only sensitive to portfolio aggregation methods but also different across stock markets. They are found to be more relevant risk characteristics in the Korean than in the Taiwan stock market.     

A novel measure of liquidity premium: application to the Korean stock market

This study proposes a novel measure for an asset’s liquidity premium. Applying Brownian first-passage time distribution properties, we derive an explicit form of liquidity premium embedded in the asset price. Our liquidity premium measure is intuitive because it assesses the extent to which the value of the asset should be increased from the current market price if investors were allowed to retain the asset until they achieve an investment goal. This measure is readily available for assessing an asset’s liquidity because it does not require information on the asset’s transactional characteristics. Our empirical experiment using Korean stock market data suggests that the liquidity premium in this study is inversely related to Amihud’s (2002) illiquidity ratio, which is commonly used to measure stocks’ illiquidity.     

Covered Call Investing in a Loss Aversion Framework

In a mean-variance framework, the covered call investment strategy has been seen as an inefficient method of allocating wealth. Covered calls reduce the riskiness of the portfolio and therefore lead to lower portfolio returns. Recent debate has focused on the shortcomings of mean-variance efficiency as an accurate depiction of investor utility. Using alternative utility functions, we find mixed support for the use of the covered call investing strategy. Using loss aversion, however, we reexamine the covered call investment decision and find it significantly enhances investor utility relative to an index portfolio investment strategy. We conclude that loss aversion's more accurate depiction of investor preferences and behavior helps to explain the popularity of the covered call investment strategy.     

Portfolio choice of financial investors and European business cycle convergence: a panel analysis for EU countries

We investigate the linkage between business cycle convergence and financial portfolio choice for a panel of 18 EU countries. We construct an index of similarity of financial portfolios which we then put into context with the view that “the financial world” has an impact on business cycles and contributes to business cycle convergence via the consumption-wealth linkage. The model which guides our analysis is the International Asset Pricing Model (IAPM). Portfolios of the 18 EU countries investigated by us turn out to become more similar over time. According to our fixed effects GMM TSLS estimations, similar portfolios contribute to a convergence of business cycles—via a convergence of consumption cycles. This turns out to be especially true for country-pairs that include euro area non-member countries and, thus, have quite different income and wealth structures.