The article presents the Yoruba ajọ system as a form of social capital in working class business finance and human development. Social capital depicts the utilization of bonds of love, friendship, trust, and kinship as productive resources. A primary factor in the formation of ajọ is the trust value, which could sustain group cohesion and survival. Data were collected through in-depth interviews (IDIs) among working class traders in six urban markets in Ibadan. A total of thirty-three IDIs were conducted. The study detailed the structure and organization of ajọ, affirmed the relevance of ajọ in business finance and human development, and also examined the challenges of the of the ajọ system.