While trust is critical to microlending groups, much less is known about the vital factors and mechanisms that foster its emergence in microlending groups. This paper examines the practices of trust building and use in microlending groups. The results suggest that trust is produced and developed in microlending groups through a combination of calculative, prediction, intentionality, capability and transference mechanisms. These mechanisms are not mutually exclusive but act together to build trust. Though trust has general characteristics, whether and how it is formed and developed in microlending groups depends on context-specific factors such as informal debt relations. Trust among group members is bolstered by multiplex relations of social events, neighbourhood, and friendship. The paper suggests that the unbanked population has a rich informal credit history.