We provide a general framework for finding portfolios that perform well out-of-sample in the presence of estimation error. This framework relies on solving the traditional minimum-variance problem ...but subject to the additional constraint that the norm of the portfolio-weight vector be smaller than a given threshold. We show that our framework nests as special cases the shrinkage approaches of Jagannathan and Ma (Jagannathan, R., T. Ma. 2003. Risk reduction in large portfolios: Why imposing the wrong constraints helps. J. Finance 58 1651–1684) and Ledoit and Wolf (Ledoit, O., M. Wolf. 2003. Improved estimation of the covariance matrix of stock returns with an application to portfolio selection. J. Empirical Finance 10 603–621, and Ledoit, O., M. Wolf. 2004. A well-conditioned estimator for large-dimensional covariance matrices. J. Multivariate Anal. 88 365–411) and the 1/ N portfolio studied in DeMiguel et al. (DeMiguel, V., L. Garlappi, R. Uppal. 2009. Optimal versus naive diversification: How inefficient is the 1/ N portfolio strategy? Rev. Financial Stud. 22 1915–1953). We also use our framework to propose several new portfolio strategies. For the proposed portfolios, we provide a moment-shrinkage interpretation and a Bayesian interpretation where the investor has a prior belief on portfolio weights rather than on moments of asset returns. Finally, we compare empirically the out-of-sample performance of the new portfolios we propose to 10 strategies in the literature across five data sets. We find that the norm-constrained portfolios often have a higher Sharpe ratio than the portfolio strategies in Jagannathan and Ma (2003), Ledoit and Wolf (2003, 2004), the 1/ N portfolio, and other strategies in the literature, such as factor portfolios.
This paper investigates the dynamics of individual portfolios in a unique data set containing the disaggregated wealth of all households in Sweden. Between 1999 and 2002, we observe little aggregate ...rebalancing in the financial portfolio of participants. These patterns conceal strong household-level evidence of active rebalancing, which on average offsets about one-half of idiosyncratic passive variations in the risky asset share. Wealthy, educated investors with better diversified portfolios tend to rebalance more actively. We find some evidence that households rebalance toward a greater risky share as they become richer. We also study the decisions to trade individual assets. Households are more likely to fully sell directly held stocks if those stocks have performed well, and more likely to exit direct stockholding if their stock portfolios have performed well; but these relationships are much weaker for mutual funds, a pattern that is consistent with previous research on the disposition effect among direct stockholders and performance sensitivity among mutual fund investors. When households continue to hold individual assets, however, they rebalance both stocks and mutual funds to offset about one-sixth of the passive variations in individual asset shares. Households rebalance primarily by adjusting purchases of risky assets if their risky portfolios have performed poorly, and by adjusting both fund purchases and full sales of stocks if their risky portfolios have performed well. Finally, the tendency for households to fully sell winning stocks is weaker for wealthy investors with diversified portfolios of individual stocks.
To obtain more funds from the institutional investors, private equity (PE) fund managers may report inflated valuations of private investee companies that are not yet sold. However, such ...overvaluations may result in a reputational cost when those investments are realized. Using evidence from 39 countries, we show that there are significant systematic biases in managers' reporting of fund performance. We find that these biases depend on the accounting and legal environment in a country, and on proxies for the degree of information asymmetry between institutional investors and PE fund managers.
Social status concerns influence investors' decisions by driving a wedge in attitudes toward aggregate and idiosyncratic risks. I model such concerns by emphasizing the desire to "get ahead of the ...Joneses," which implies that aversion to idiosyncratic risk is lower than aversion to aggregate risk. The model predicts that investors hold concentrated portfolios in equilibrium, which helps rationalize the small premium for undiversified entrepreneurial risk. In the model, status concerns are more important for wealthier households. Consequently, these households own a disproportionate share of risky assets, particularly private equity, and experience greater volatility of consumption, consistent with empirical evidence.
Using data on identical and fraternal twins’ complete financial portfolios, we decompose the cross-sectional variation in investor behavior. We find that a genetic factor explains about one-third of ...the variance in stock market participation and asset allocation. Family environment has an effect on the behavior of young individuals, but this effect is not long-lasting and disappears as an individual gains experience. Frequent contact among twins results in similar investment behavior beyond a genetic factor. Twins who grew up in different environments still display similar investment behavior. Our interpretation of a genetic component of the decision to invest in the stock market is that there are innate differences in factors affecting effective stock market participation costs. We attribute the genetic component of asset allocation—the relative amount invested in equities and the portfolio volatility—to genetic variation in risk preferences.
The paper examines the performance of several multivariate volatility models, namely CCC, VARMA-GARCH, DCC, BEKK and diagonal BEKK, for the crude oil spot and futures returns of two major benchmark ...international crude oil markets, Brent and WTI, to calculate optimal portfolio weights and optimal hedge ratios, and to suggest a crude oil hedge strategy. The empirical results show that the optimal portfolio weights of all multivariate volatility models for Brent suggest holding futures in larger proportions than spot. For WTI, however, DCC, BEKK and diagonal BEKK suggest holding crude oil futures to spot, but CCC and VARMA-GARCH suggest holding crude oil spot to futures. In addition, the calculated optimal hedge ratios (OHRs) from each multivariate conditional volatility model give the time-varying hedge ratios, and recommend to short in crude oil futures with a high proportion of one dollar long in crude oil spot. Finally, the hedging effectiveness indicates that diagonal BEKK (BEKK) is the best (worst) model for OHR calculation in terms of reducing the variance of the portfolio.
We develop a one-period model of investor asset holdings where investors have heterogeneous preference for skewness. Introducing heterogeneous preference for skewness allows the model's investors, in ...equilibrium, to underdiversify. We find support for our model's three key implications using a dataset of 60,000 individual investor accounts. First, we document that the portfolio returns of underdiversified investors are substantially more positively skewed than those of diversified investors. Second, we show that the apparent mean-variance inefficiency of underdiversified investors can be largely explained by the fact that investors sacrifice mean-variance efficiency for higher skewness exposure. Furthermore, we show that idiosyncratic skewness, and not just coskewness, can impact equilibrium prices. Third, the underdiversification of investors does not appear to be coincidentally related to skewness. Stocks most often selected by underdiversified investors have substantially higher average skewness-especially idiosyncratic skewness-than stocks most often selected by diversified investors.
Portfolio Choice with Illiquid Assets Ang, Andrew; Papanikolaou, Dimitris; Westerfield, Mark M.
Management science,
11/2014, Letnik:
60, Številka:
11
Journal Article
Recenzirano
Odprti dostop
We present a model of optimal allocation to liquid and illiquid assets, where illiquidity risk results from the restriction that an asset cannot be traded for intervals of uncertain duration. ...Illiquidity risk leads to increased and state-dependent risk aversion and reduces the allocation to both liquid and illiquid risky assets. Uncertainty about the length of the illiquidity interval, as opposed to a deterministic nontrading interval, is a primary determinant of the cost of illiquidity. We allow market liquidity to vary from “normal” periods, when all assets are fully liquid, to “illiquidity crises,” when some assets can only be traded infrequently. The possibility of a liquidity crisis leads to limited arbitrage in normal times. Investors are willing to forgo 2% of their wealth to hedge against illiquidity crises occurring once every 10 years.
This paper was accepted by Itay Goldstein, finance.
► We propose a constrained minimum-variance portfolio strategy. ► New strategy is based on a shrinkage theory based framework. ► Our policy improves the performance of the benchmark strategies ...substantially. ► Turnover and short interest are only moderately increased. ► We validate our strong performance with established bootstrap methods.
We reassess the recent finding that no established portfolio strategy outperforms the naively diversified portfolio, 1/N, by developing a constrained minimum-variance portfolio strategy on a shrinkage theory based framework. Our results show that our constrained minimum-variance portfolio yields significantly lower out-of-sample variances than many established minimum-variance portfolio strategies. Further, we observe that our portfolio strategy achieves higher Sharpe ratios than 1/N, amounting to an average Sharpe ratio increase of 32.5% across our six empirical datasets. We find that our constrained minimum-variance strategy is the only strategy that achieves the goal of improving the Sharpe ratio of 1/N consistently and significantly. At the same time, our developed portfolio strategy achieves a comparatively low turnover and exhibits no excessive short interest.
A major puzzle in international finance is that high interest rate currencies tend to appreciate (forward discount puzzle). Motivated by the fact that only a small fraction of foreign currency ...holdings is actively managed, we calibrate a two-country model in which agents make infrequent portfolio decisions. We show that the model can account for the forward discount puzzle. It can also account for several related empirical phenomena, including that of "delayed overshooting." We also show that making infrequent portfolio decisions is optimal as the welfare gain from active currency management is smaller than the corresponding fees.
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