In this paper we show that the 3SLS estimator of a system of equations is asymptotically equivalent to an iterative 2SLS estimator applied to each equation, augmented with the residuals from the other equations. This result is a natural extension of Telser (1964).

In this paper, we consider efficient estimation of coefficients of interest in seemingly unrelated regressions (SUR) models. Using the GMM interpretation of the usual OLS and GLS/FGLS estimation of regression coefficients in SUR models, we derive the necessary and sufficient condition for the...