The limits of diversification when losses may be large

Recent results in value at risk analysis show that, for extremely heavy-tailed risks with unbounded distribution support, diversification may increase value at risk, and that generally it is difficult to construct an appropriate risk measure for such distributions. We further analyze the limitations of diversification for heavy-tailed risks. We provide additional insight in two ways. First, we show that similar non-diversification results are valid for a large class of risks with bounded support, as long as the risks are concentrated on a sufficiently large interval. The required length of the support depends on the number of risks available and on the degree of heavy-tailedness. Second, we relate the value at risk approach to more general risk frameworks. We argue that in markets for risky assets where the number of assets is limited compared with the (bounded) distribution support of the risks, unbounded heavy-tailed risks may provide a reasonable approximation. We suggest that this type of analysis may have a role in explaining various types of market failures in markets for assets with possibly large negative outcomes.     

Asset market linkages: Evidence from financial, commodity and real estate assets

We use a general Markov switching model to examine the relationships between returns over three different asset classes: financial assets (US stocks and Treasury bonds), commodities (oil and gold) and real estate assets (US Case-Shiller index). We confirm the existence of two distinct regimes: a “tranquil” regime with periods of economic expansion and a “crisis” regime with periods of economic decline. The tranquil regime is characterized by lower volatility and significantly positive stock returns. During these periods, there is also evidence of a flight from quality - from gold to stocks. By contrast, the crisis regime is characterized by higher volatility and sharply negative stock returns, along with evidence of contagion between stocks, oil and real estate. Furthermore, during these periods, there is strong evidence of a flight to quality - from stocks to Treasury bonds.     

Non-Gaussian diversification: When size matters

Classical portfolio theory informs investors that they should have a large number of assets in their portfolios in order to diversify risk. We show that the non-Gaussian features of stock return distribution may not allow for this risk protection in times of crisis. Moreover, we demonstrate empirically that, if investors are risk-averse and consider higher order moments, they have numerous incentives not to diversify their portfolios fully. This is caused by the evolution of both large losses and asymmetry of returns when the numbers of assets in a portfolio change.     

International portfolio diversification is better than you think

Using aggregate data on bilateral cross-border equity holdings, we investigate whether investors correctly hedge their over-exposure to domestic risk (the well-known equity home bias) by investing in foreign stock markets that have low correlation with their home stock market. To deal with the endogeneity of stock return correlations, we instrument current correlations with past correlations. Controlling for many determinants of international portfolios, we find that, all else equal, investors do tilt their foreign holdings towards countries, which offer better diversification opportunities. The diversification motive that we uncover is stronger for source countries exhibiting a higher level of home bias.     

Do sovereign credit default swaps represent a clean measure of sovereign default risk? A factor model approach

In this study, we use a factor model in order to decompose sovereign Credit Default Swaps (CDS) spreads into default, liquidity, systematic liquidity and correlation components. By calibrating the model to sovereign CDSs and bonds we are able to present a better decomposition and a more accurate measure of spread components. Our analysis reveals that sovereign CDS spreads are highly driven by liquidity (55.6% of default risk and 44.32% of liquidity) and that sovereign bond spreads are less subject to liquidity frictions and therefore could represent a better proxy for sovereign default risk (73% of default risk and 26.86% of liquidity). Furthermore, our model enables us to directly study the effect of systematic liquidity and flight-to-liquidity risks on bond and CDS spreads through the factor sensitivity matrix. We find that these risks do have an influence on the default intensity and they contribute significantly to spread movements. Finally, our empirical results advance the idea that the increase in the CDS spreads observed during the crisis period was mainly due to a surge in liquidity rather than to an increase in the default intensity.     

Does information drive trading in option strategies?

We study trading in option strategies in the FTSE-100 index market. Trades in option strategies represent around 37% of the total number of trades and over 75% of the total trading volume in our sample. We find some evidence that order flow in volatility–sensitive option strategies contains information about future realized volatility. We do not find evidence that order flow in directionally–sensitive option strategies contains information about future returns. Overall, our evidence suggests that option strategies are used both by traders who possess non-public information about future volatility and by uninformed speculators who appear to follow unprofitable trend chasing strategies.     

REGULAR(IZED) HEDGE FUND CLONES

This article addresses the problem of portfolio construction in the context of efficient hedge fund investments replication. We propose a modification to the standard Sharpe “style analysis” by introducing a constraint on the asset weights 1‐norm and 2‐norm. This constraint regularizes the optimization problem, allows efficient selection of relevant factor's and has significant effects on the stability of the resulting asset mix and the risk–return characteristics of the replicating portfolio. The empirical results suggest that the norm‐constrained replicating portfolios exhibit significant correlations with their benchmarks, often higher than 0.9; have a fraction, which is about half to two‐thirds, of active positions relative to those determined through the standard method; and are obtained with turnover, which is in some instances about one‐fourth of that for the standard method.     

Portfolio insurance and prospect theory investors: Popularity and optimal design of capital protected financial products

Portfolio insurance strategies are used on both the institutional and the retail side of the asset management industry. While standard utility theory struggles to provide an explanation, this study justifies the popularity of portfolio insurance strategies in a behavioral finance context. We run Monte Carlo simulations as well as historical simulations for popular portfolio insurance strategies and benchmark strategies in order to evaluate the outcomes using cumulative prospect theory. Our simulation results indicate that most portfolio insurance strategies are the preferred investment strategy for a prospect theory investor. Moreover, the analysis provides insights into how portfolio insurance products should be designed and structured to meet the preferences of prospect theory investors as accurately as possible.     

When are path-dependent payoffs suboptimal?

Generalizing a result by  and , this note shows that risk-averse investors with fixed planning horizon prefer path-independent payoffs in any financial market if the pricing kernel is a function of the underlying’s price at the end of the planning horizon. Generally, for every payoff which is not a function of the pricing kernel, there is a more attractive alternative that depends solely on the pricing kernel at the end of the planning horizon.     

CAPM and APT-like models with risk measures

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.     

Time diversification: Definitions and some closed-form solutions

We establish general conditions under which younger investors should invest a larger proportion of their wealth in risky assets than older ones. In the finite horizon dynamic setting, we show that such phenomenon, known as ‘‘time diversification,” can occur in the presence of human wealth, guaranteed consumption, or mean-reverting stock returns. We formalize two alternative notions of time diversification commonly confounded in the literature. Analytic solutions are provided for both time-series and cross-sectional forms of time diversification. To our best knowledge, this paper is the first to solve in closed-form the hedging demand for a CARA investor with inter-temporal consumption and a finite horizon, facing mean-reverting expected returns. Our results indicate that horizon can have a significant effect on the portfolio demand of a CARA investor due to inter-temporal hedging.     

International diversification with securitized real estate and the veiling glare from currency risk

This paper analyzes diversification benefits from international securitized real estate in a mixed-asset context. We apply regression-based mean-variance efficiency tests, conditional on currency-unhedged and fully hedged portfolios to account for systematic foreign exchange movements. From the perspective of a US investor, it is shown that, first, international diversification is superior to a US mixed-asset portfolio, second, adding international real estate to an already internationally diversified stock and bond portfolio results in a further significant improvement of the risk-return trade-off and, third, considering unhedged international assets could lead to biased asset allocation decisions not realizing the true diversification benefits from international assets.     

On the diversification benefits of commodities from the perspective of euro investors

This paper investigates the diversification contribution of several commodities to a portfolio of traditional assets from the perspective of a euro investor. The approach applied in our analysis has high informational content as it differentiates between the sources of the diversification benefits in a statistically significant way. The results indicate that the diversification contribution varies greatly amongst the different commodities. Industrial metals, agriculturals and livestock contribute to the reduction of risk, while energy and precious metals contribute to both the reduction of the level of risk and to the improvement of return. The differentiation between bull and bear markets reveals that investors can enhance the portfolio performance by changing exposure into individual commodities. Investors can benefit from the diversification gains through financial instruments as the diversification gains hold both in the sample of physical commodity and commodity futures. Overall, the results confirm that commodities are valuable investments from the perspective of diversification.     

Limits to arbitrage and hedging: Evidence from commodity markets

We build an equilibrium model of commodity markets in which speculators are capital constrained, and commodity producers have hedging demands for commodity futures. Increases in producers' hedging demand or speculators' capital constraints increase hedging costs via price-pressure on futures. These in turn affect producers' equilibrium hedging and supply decision inducing a link between a financial friction in the futures market and the commodity spot prices. Consistent with the model, measures of producers' propensity to hedge forecasts futures returns and spot prices in oil and gas market data from 1979 to 2010. The component of the commodity futures risk premium associated with producer hedging demand rises when speculative activity reduces. We conclude that limits to financial arbitrage generate limits to hedging by producers, and affect equilibrium commodity supply and prices.     

International portfolio diversification benefits: Cross-country evidence from a local perspective

We investigate how the benefits of international portfolio diversification differ across countries from the perspective of a local investor. We find that the benefits of investing abroad are largest for investors in developing countries, including when controlling for currency effects. Most of the benefits are obtained from investing outside the region of the home country. These global diversification benefits remain large when controlling for short-sales constraints in developing stock markets. The gains from international portfolio diversification appear to be largest for countries with high country risk. In addition to this cross-sectional evidence, we also provide evidence that diversification benefits vary over time as country risk changes. We find that diversification benefits have decreased for most countries in our sample over the past two decades.     

Cross-section of option returns and volatility

We study the cross-section of stock option returns by sorting stocks on the difference between historical realized volatility and at-the-money implied volatility. We find that a zero-cost trading strategy that is long (short) in the portfolio with a large positive (negative) difference between these two volatility measures produces an economically and statistically significant average monthly return. The results are robust to different market conditions, to stock risks-characteristics, to various industry groupings, to option liquidity characteristics, and are not explained by usual risk factor models.     

Two counters of jumps

This paper introduces a class of two counters of jumps option pricing models. The stock price follows a jump-diffusion process with price jumps up and price jumps down, where each type of jumps can have different means and standard deviations. Price jumps can be negatively autocorrelated as it has been observed in practice. We investigate the volatility surfaces generated by this class of two counters of jumps option pricing models. Our formulae, like the jump-diffusion models with a single counter of jumps, are able to generate smiles, and skews   with similar shapes to those observed in the options markets. More importantly, unlike the jump-diffusion models with a single counter of jumps, our formulae are able to generate term structures of implied volatilities of at-the-money options with ∩$\cap$-shaped patterns similar to those observed in the marketplace.     

Portfolio diversification benefits within Europe: Implications for a US investor

This paper investigates the possibility of cointegration between the United States and 11 European equity markets before and after the convergence period of 1995. The results indicate that during the preconvergence and postconvergence periods, some country groups, with and without the US equity market, exhibited cointegration while others did not. For the European Union markets, however, at least one cointegrating vector emerged in either period, but no cointegration among them surfaced during the Euro introduction period of 1999. These results suggest that a US investor can still benefit from country diversification within the European Union markets.     

International diversification gains and home bias in banking

This paper studies international diversification in banking, exploiting a bank-level dataset that covers the operations of 38 global banks and their subsidiaries overseas during 1995–2004. The paper finds that banks with a larger share of assets allocated to subsidiaries in emerging market countries were able to attain higher risk-adjusted returns. These gains were somewhat reduced by the concentration of bank subsidiaries in specific geographical regions, which is typical of the observed international expansion strategies. The paper also finds a substantial home bias in the international allocation of bank assets relative to the results of a mean–variance portfolio optimization model.     

Corporate taxes,strategic default,and the cost of debt

The current US tax code’s loss carry provisions provide implicit tax subsidies to financially troubled firms. Since shareholders ultimately decide when to announce bankruptcy, such tax subsidies can incentivize them to strategically postpone default. Therefore, corporate taxation can influence corporate cost of debt. Using a large panel of corporate bonds, we find supporting evidence: credit spreads become smaller as tax loss carries grow larger. In contrast, tax shields such as depreciation, which limit loss carry gains, lead to wider spreads. Interestingly, when stockholders hold greater bargaining power – due to large managerial ownership – larger corporate tax shields lead to even narrower credit spreads.