This paper proposes a new instrumental variables approach for consistent and asymptotically efficient estimation of panel data models with weakly exogenous or endogenous regressors and residuals generated by a multifactor error structure. In this case, the standard dynamic panel estimators fail...

If stock prices followed a random walk, uncertainty about future stock prices would be so great that the observed bias towards equities in long-term investment portfolios would be surprising. The good news is that if, as a growing body of research suggests, there is even a weak tendency for...