["Journal of Applied Econometrics, EarlyView. ", "\nABSTRACT\nThis paper explores the existence of network externalities in link formation games of incomplete information. It extends the structural estimation method in Leung (2015) to games where links are undirected and proposals are only partially observed. We provide an econometric characterization of the proposed two‐step estimator and document its performance through a simulation exercise. When the estimation method is applied to data on risk‐sharing arrangements in a Tanzanian village, results indicate that indirect connections matter.\n"]