The surge in international asset trade since the early 1990s has lead to renewed interest in models with international portfolio choice, an aspect that was largely cast aside when the ad-hoc portfolio balance models of the 1970s were replaced bymodels of optimizing agents. We develop the...

Considered here is on-line portfolio management aimed at maximizing the long-run growth of financial wealth. The portfolio is repeatedly rebalanced in response to observed returns on diverse assets. Suppose statistical information and related methods are not available - or deemed too diffcult....

The paper shows that financial market equilibria need not exist if agents possess cumulative prospect theory preferences with piecewise-power value functions. The reason is an infiniteshort-selling problem. But even when a short-sell constraint is added, non-existence can occur due to...

This paper investigates model risk issues in the context of mean-variance portfolio selection. We analytically and numerically show that, under model misspecification, the use of statistically robust estimates instead of the widely used classical sample mean and covariance is highly beneficial...