We provide a simple identity that decomposes a product moment of multivariate normal random variables as a sum of various products of univariate moments of one of the random variables and multivariate moments of the other random variables. The new identity allows for much faster computation of...

We present a simple stochastic representation for the joint distribution of sample estimates of three scalar parameters and two vectors of portfolio weights that characterize the minimum-variance frontier. This stochastic representation is useful for sampling observations efficiently, deriving...

Many matrix-valued functions of an mxm Wishart matrix W, F_k(W), say, are homogeneous of degree k in W, and are equivariant under the conjugate action of the orthogonal group O(m), i.e., F_k(HWH')=HF_k(W)H', H \in O(m). It is easy to see that the expectation of such a function is itself...

The paper discusses the moments of Wishart matrices, in both the central and noncentral cases. The first part of the paper shows that the expectation map has certain homogeneity and equivariance properties which impose considerable structure on the moments, hitherto unrecognised. The second part...

In this paper, we provide an exact finite sample analysis of predictive regressions with overlapping long-horizon returns. This analysis allows us to evaluate the reliability of various asymptotic theories for predictive regressions in finite samples. In addition, our finite sample analysis...

We present a new finding that the return autocorrelation of underlying stock is an important determinant of expected equity option returns. Using an extended Black-Scholes model incorporating the presence of stock return autocorrelation, we show that expected returns of both call and put options...

Mimicking portfolios for factors are often used in asset pricing studies. Current practice has generally ignored the impact of estimation errors on the weights of the mimicking portfolios. We show that such a practice can lead to gross understatement of the standard errors of the estimated risk...