Public family firms in India represent an interesting case of relatively high ownership concentration combined with high growth opportunities, less competitive product markets and less developed capital markets. Investigating the relationship between ownership concentration and stock market performance, our initial analysis indicates insignificant average abnormal stock returns at low levels of family holdings but weak positive performance at high levels of ownership in the full sample of family and non-family firms and the family subsample. These aggregate results appear robust to alternative metrics of abnormal performance, controls for founder, descendant, and outside CEOs. Further analysis of subsamples of less and more competitive product markets indicates that while the vast majority of family firms enjoying high growth opportunities in less competitive market environments exhibit poor performance at lower ownership levels, those firms with higher family holdings are associated with significantly positive abnormal returns. However, the relation between family ownership and firm valuation under high growth prospects becomes insignificant for a much smaller fraction of firms facing high product market competition. Overall, our results are consistent with the hypothesis that positive alignment of interest effects offset family entrenchment effects on firm performance at high levels of ownership concentration common in India where most firms face high growth opportunities and less product market competition. These results challenge the evidence in western developed economies marked by relatively weaker growth rates and stronger product market rivalry that the performance of family firms tends to decline at high ownership concentration due to entrenchment. © 2020 Elsevier B.V.