This study is based on an interpretive content analysis of oral history data and documentary data on ethnic Indian and Chinese entrepreneurs in Singapore and their enterprises. This data is complemented by personal interviews with family members, informants and business community leaders, as well as historical analysis. The data reveals that most ethnic Indian entrepreneurs maintained their trade specializations and family management, whereas most ethnic Chinese entrepreneurs pursued unrelated diversification and incorporated outsiders into their operational management over time. What is particularly intriguing is the existence of an intra-ethnic division in business structure among the ethnic Indian enterprises. I argue that the opportunity structure in the country of residence and ethnic resources play only a limited role in shaping the differential management and business structures of the two ethnic groups. Rather, I attribute such differences primarily to the differential strength of ties of the entrepreneurs to their region/dialect-based networks. The strength of the ties reflects the degree of intra-community homogeneity and inter-community heterogeneity. These arguments are presented in the form of hypothesized relationships for future validation. The paper concludes with a critique of the structuralist, culturalist and interactionist perspectives on ethnic entrepreneurship, and suggests directions for future research into intra-ethnic entrepreneurship, comparative business systems and the paradox of embeddedness.