This paper aims to systematically examine the impact of Chinese migrants on the economic activities of indigenous Chinese firms from two dimensions: foreign direct investment (FDI) by ethnic Chinese (ECI) and returnees. Using a unique data set for firms in Zhongguancun Science Park, Beijing, we carry out an in‐depth empirical study on the effects of ECI and returnees on indigenous Chinese firms’ productivity, exports and R&D in comparison with the effects of non‐ethnic Chinese FDI. The findings have important policy implications.