Research on business groups' legally independent firms tied together in various formal and informal ways¿is accelerating. Through meta-analytical techniques employed on a database of 141 studies covering 28 different countries, we synthesize this research and extend it by testing several new hypotheses. We find that affiliation diminishes firm performance in general, but also that affiliates are comparatively better off in contexts with underdeveloped financial and labor market institutions. We also trace reduced affiliate performance to specific strategic actions taken at the firm and group levels. Overall, our results indicate that affiliate performance reflects complex processes and motivations.