This paper examines how participation in a microfinance program spreads through social networks, using data from 43 villages in southern India. The study uses detailed demographic, social network, and participation data to analyze how the initial "injection points" — individuals first informed about the program — influence diffusion. It finds that participation is significantly higher when these injection points have higher eigenvector centrality, indicating their importance in the network. The study also estimates structural models of diffusion to distinguish between information transmission and peer influence. It finds that participants are more likely to pass information to friends than non-participants, but non-participants still play a significant role in spreading information, accounting for about one-third of informedness and participation. The study also finds that once individuals are informed, their participation is not significantly affected by the participation of their acquaintances. The paper highlights the importance of social networks in microfinance diffusion and the role of injection points in this process. It also discusses the limitations of traditional models of diffusion and the need for more nuanced approaches that account for both information and endorsement effects. The study uses a combination of reduced-form and structural approaches to analyze the diffusion of microfinance participation, finding that social networks play a crucial role in this process. The results suggest that the diffusion of microfinance is influenced by both the structure of social networks and the characteristics of individuals within those networks. The study provides evidence that social networks are important in the diffusion of microfinance and that the initial injection points play a key role in this process. The paper also discusses the limitations of traditional models of diffusion and the need for more nuanced approaches that account for both information and endorsement effects. The study uses a combination of reduced-form and structural approaches to analyze the diffusion of microfinance participation, finding that social networks play a crucial role in this process. The results suggest that the diffusion of microfinance is influenced by both the structure of social networks and the characteristics of individuals within those networks.This paper examines how participation in a microfinance program spreads through social networks, using data from 43 villages in southern India. The study uses detailed demographic, social network, and participation data to analyze how the initial "injection points" — individuals first informed about the program — influence diffusion. It finds that participation is significantly higher when these injection points have higher eigenvector centrality, indicating their importance in the network. The study also estimates structural models of diffusion to distinguish between information transmission and peer influence. It finds that participants are more likely to pass information to friends than non-participants, but non-participants still play a significant role in spreading information, accounting for about one-third of informedness and participation. The study also finds that once individuals are informed, their participation is not significantly affected by the participation of their acquaintances. The paper highlights the importance of social networks in microfinance diffusion and the role of injection points in this process. It also discusses the limitations of traditional models of diffusion and the need for more nuanced approaches that account for both information and endorsement effects. The study uses a combination of reduced-form and structural approaches to analyze the diffusion of microfinance participation, finding that social networks play a crucial role in this process. The results suggest that the diffusion of microfinance is influenced by both the structure of social networks and the characteristics of individuals within those networks. The study provides evidence that social networks are important in the diffusion of microfinance and that the initial injection points play a key role in this process. The paper also discusses the limitations of traditional models of diffusion and the need for more nuanced approaches that account for both information and endorsement effects. The study uses a combination of reduced-form and structural approaches to analyze the diffusion of microfinance participation, finding that social networks play a crucial role in this process. The results suggest that the diffusion of microfinance is influenced by both the structure of social networks and the characteristics of individuals within those networks.