Modern portfolio management with conditioning information

This paper studies models in which active portfolio managers utilize conditioning information unavailable to their clients to optimize performance relative to a benchmark. We derive explicit solutions for the optimal strategies with multiple risky assets, with or without a risk-free asset, and consider various constraints on portfolio risks or weights. The optimal strategies feature a mean–variance efficient component (to minimize portfolio variance), and a hedging demand for the benchmark portfolio (to maximize correlation with the benchmark). A currency portfolio example shows that the optimal strategies improve the measured performance by 53% out of sample, compared with portfolios ignoring conditioning information.     

Portfolio selection with a drawdown constraint

When identifying optimal portfolios, practitioners often impose a drawdown constraint. This constraint is even explicit in some money management contracts such as the one recently involving Merrill Lynch’ management of Unilever’s pension fund. In this setting, we provide a characterization of optimal portfolios using mean–variance analysis. In the absence of a benchmark, we find that while the constraint typically decreases the optimal portfolio’s standard deviation, the constrained optimal portfolio can be notably mean–variance inefficient. In the presence of a benchmark such as in the Merrill Lynch–Unilever contract, we find that the constraint increases the optimal portfolio’s standard deviation and tracking error volatility. Thus, the constraint negatively affects a portfolio manager’s ability to track a benchmark.     

Benchmarking the performance of recommended allocations to equities,bonds, and cash by international investment houses

We conduct performance tests of the recommended asset allocations made by a panel of international investment houses (the “Houses”) from 1982 through 2005. We compare the returns and Sharpe Ratios from the recommended-weight portfolio against those of several benchmark portfolios and to a set of 10,000 returns and Sharpe Ratios from randomly shuffled-weight and shuffled-weight change portfolios. We find that the Houses generally fail to outperform the benchmarks. The shuffled-weight change benchmark exhibits a robust “style-preserving” property in that the average portfolio standard deviation is nearly equal to the portfolio standard deviation from the actual recommended weights.     

Linear programing models for portfolio optimization using a benchmark

We consider the problem of constructing a perturbed portfolio by utilizing a benchmark portfolio. We propose two computationally efficient portfolio optimization models, the mean-absolute deviation risk and the Dantzig-type, which can be solved using linear programing. These portfolio models push the existing benchmark toward the efficient frontier through sparse and stable asset selection. We implement these models on two benchmarks, a market index and the equally-weighted portfolio. We carry out an extensive out-of-sample analysis with 11 empirical datasets and simulated data. The proposed portfolios outperform the benchmark portfolio in various performance measures, including the mean return and Sharpe ratio.     

Cardinality versus q-norm constraints for index tracking

Index tracking aims at replicating a given benchmark with a smaller number of its constituents. Different quantitative models can be set up to determine the optimal index replicating portfolio. In this paper, we propose an alternative based on imposing a constraint on the q-norm (0?<?q?<?1) of the replicating portfolios’ asset weights: the q-norm constraint regularises the problem and identifies a sparse model. Both approaches are challenging from an optimization viewpoint due to either the presence of the cardinality constraint or a non-convex constraint on the q-norm. The problem can become even more complex when non-convex distance measures or other real-world constraints are considered. We employ a hybrid heuristic as a flexible tool to tackle both optimization problems. The empirical analysis of real-world financial data allows us to compare the two index tracking approaches. Moreover, we propose a strategy to determine the optimal number of constituents and the corresponding optimal portfolio asset weights.     

Measuring bond mutual fund performance with portfolio characteristics

This paper studies the performance of U.S. bond mutual funds using measures constructed from a novel data set of portfolio weights. Active fund managers exhibit outperformance before costs and fees generating, on average, gross returns of 1% per annum over the benchmark portfolio constructed using past holdings (approximately the same magnitude as expenses and transaction costs combined). This suggests that fund managers are able to earn back their fees and costs. There is evidence of neutral ability to time different portfolio allocations (sector, credit quality, and portfolio maturity allocations) and only a subgroup of bond funds exhibit successful timing ability. One performance measure based on portfolio holdings predicts future fund performance and provides information not contained in the standard measures. These results provide the first evidence of the value of active management in bond mutual funds.     

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.     

Econometrics of efficient fitted portfolios

In this paper we propose a mean variance analysis of the portfolio choice under constraints. An efficient portfolio under constraint is called fitted. We show that the fitted portfolios can consistently be estimated and used to assess the performances of the portfolio management. The explicit formula of the individual demand function for assets is also derived, and generalizes the demand function of the standard portfolio choice theory. The performance measures and associated statistics can be used to test the hypothesis of the portfolio efficiency under constraint. Moreover, we explain how to estimate subsets of constraints faced by an individual. Finally, we show that our framework is also adequate for the analysis of incomplete information.     

Portfolio risk management in a data-rich environment

We study risk assessment using an optimal portfolio in which the weights are functions of latent factors and firm-specific characteristics (hereafter, diffusion index portfolio). The factors are used to summarize the information contained in a large set of economic data and thus reflect the state of the economy. First, we evaluate the performance of the diffusion index portfolio and compare it to both that of a portfolio in which the weights depend only on firm-specific characteristics and an equally weighted portfolio. We then use value-at-risk, expected shortfall, and downside probability to investigate whether the weights-modeling approach, which is based on factor analysis, helps reduce market risk. Our empirical results clearly indicate that using economic factors together with firm-specific characteristics helps protect investors against market?risk.     

The performance of international asset allocation strategies using conditioning information

The existence of predictable components in conditional expected returns has been widely reported. We propose a test of the economic significance of this phenomenon by designing dynamic international allocation strategies based on a conditioning information set. We compare the performance of these dynamic strategies with some market portfolio benchmark and with unconditionally efficient portfolios (among the set of primitive assets). We find the performance of the dynamic strategies to be superior. The difference is not only statistically significant, it is economically large.     

Parameter uncertainty in portfolio selection: Shrinking the inverse covariance matrix

The estimation of the inverse covariance matrix plays a crucial role in optimal portfolio choice. We propose a new estimation framework that focuses on enhancing portfolio performance. The framework applies the statistical methodology of shrinkage directly to the inverse covariance matrix using two non-parametric methods. The first minimises the out-of-sample portfolio variance while the second aims to increase out-of-sample risk-adjusted returns. We apply the resulting estimators to compute the minimum variance portfolio weights and obtain a set of new portfolio strategies. These strategies have an intuitive form which allows us to extend our framework to account for short-sale constraints, transaction costs and singular covariance matrices. A comparative empirical analysis against several strategies from the literature shows that the new strategies often offer higher risk-adjusted returns and lower levels of risk.     

Multivariate Shrinkage for Optimal Portfolio Weights

Abstract

This paper proposes a multivariate shrinkage estimator for the optimal portfolio weights. The estimated classical Markowitz weights are shrunk to the deterministic target portfolio weights. Assuming log asset returns to be i.i.d. Gaussian, explicit solutions are derived for the optimal shrinkage factors. The properties of the estimated shrinkage weights are investigated both analytically and using Monte Carlo simulations. The empirical study compares the competing portfolio selection approaches. Both simulation and empirical studies show that the proposed shrinkage estimator is robust and provides significant gains to the investor compared to benchmark procedures.     

Long-Term Synthetic Puts

We present the possibility of replicating the performance of a long-term put, which is not available in the financial markets, by a set of other traded financial assets. First, a benchmark portfolio is formed out of one share of stock and one put on the stock with a certain exercise price and a long time until maturity. The general form of a portfolio, consisting of shares of stock, bonds, and options on the stock, is discussed, which is expected to perform like the benchmark portfolio. Then a class of these synthetic puts is examined to determine which type of synthetic put may dominate the others.     

Social comparison of cost behaviour and financial analysts

We investigate whether social comparison of a firm’s reported selling, general and administrative (SG&A) expenses affects financial analysts’ information uncertainty (and their behaviour). Based on a sample of US firms, we examine whether similarity of a firm’s SG&A to an industry-specific peer-based benchmark (or social benchmark) is associated with analyst forecast dispersion, forecast error and coverage. For external observers, the SG&A relative to sales (SG&A ratio) is a key diagnostic of a firm’s cost behaviour, but interpretational ambiguity of the SG&A signal is likely to incentivise search for information-relevant external cues to set expectations about and assess a firm’s SG&A ratio. Higher similarity to the social benchmark is expected to attenuate information asymmetry between analysts and firms regarding firms’ ability to effectively control overheads, decreasing analyst information uncertainty about cost behaviour and performance. In line with a varying weights model for social comparison, we observe a negative association between SG&A similarity and both forecast dispersion and error of one-year-ahead earnings for firms with a prior SG&A ratio exceeding the social benchmark. Our findings also show a negative relationship between SG&A similarity and analyst coverage, especially for firms with a prior SG&A ratio exceeding the social benchmark.     

Implied measures of relative fund performance

We evaluate the relative performance of funds by conditioning their returns on the cross-section of portfolio characteristics across fund managers. Our implied procedure circumvents the need to specify benchmark returns or peer funds. Instead, fund-specific benchmarks for measuring selection and market timing ability are constructed. This technique is robust to herding as well as window dressing and mitigates survivorship bias. Empirically, the conditional information contained in portfolio weights defined by industry sectors, assets, and geographical regions is important to the assessment of fund management. For each set of portfolio characteristics, we identify funds with success at either selecting securities or timing-the-market.

A semiparametric model for the systematic factors of portfolio credit risk premia

The aim of this paper is to investigate the empirical relationship between daily fluctuations in the risk premium for holding a large diversified credit portfolio, which we approximate by a benchmark credit index, and some tradeable market factors which capture systematic risk. The analysis is based on an adaptive nonparametric modelling approach which allows for the data-driven estimation of the nonlinear dynamic relationship between portfolio credit risk premia and their hypothetical components. Our main finding is that the empirical weights of the systematic factors display sudden jumps during market crises and a less intense time-dependent behaviour during normal market conditions. In addition, we find that during market crises the directions of the empirical relationships are often inconsistent with ordinary economic intuition, as they are influenced by the specific circumstances of financial markets distress.     

Performance aspects of Greek bond mutual funds

This paper examines the performance characteristics of Greek bond funds and the impact of fund flows on portfolio returns. The evidence shows that on average bond funds do not offer risk-adjusted profits exceeding the returns of the benchmark index, which is in consistence with the US and international evidence. Returns before fees are slightly superior to the returns of the benchmark index, but when fees are considered they lag considerably. The security selection and market timing skills of fund managers are also tested using both an unconditional and a conditional model to test for the impact of public information variables. We also find that fund flows impact negatively on market timing.     

The dynamics of portfolio management contracts

We consider the multiperiod relationship between a client anda portfolio manager and the resulting problem of motivatinga manager of unknown ability to acquire valuable information.We explore the contractual form and the optimal retention policyof the client and find that the optimal initial set of contractsfeatures a smaller performance based fee component paid to themanager than in a first-best contract, and the contract choiceelicits only partial information about the manager. As a result,ex post performance measurement is critical to future recontracting.In general, managers are retained only if the returns on theirportfolio exceed the benchmark by an appropriate amount.     

Paying for Minimum Interest Rate Guarantees: Who Should Compensate Who?

Defined contribution pension schemes often have a mandatory minimum interest rate guarantee as an integrated part of the contract. The guarantee is an embedded put option issued by the institution to the individual who is forced to invest in the option. As argued in this paper, the individual may in this way face a constraint on the feasible set of portfolio choices. We quantify the effect of the minimum interest rate guarantee constraint and demonstrate that guarantees may induce a significant utility loss. We also consider the effects of the interest rate guarantee in the case of heterogenous investors sharing a common portfolio on a pro rata basis.