a b s t r a c tSocial capital is frequently used to explain many policy related outcomes, but research has not adequately explained how it is accumulated. It is unclear whether the economic or social characteristics of others in a social network motivate social capital accumulation. This lack of understanding has called some to question social capital's efficacy. Employing data from a survey of randomly selected foreign-born Mexicans in Los Angeles County, the influence of social and economic characteristics of a migrant's social network members are estimated. Results suggest a negative association with social capital accumulation for Mexican migrants with a social network member outside their neighborhood. Having married social network members is positively associated for legal Mexicans, while having network members who work in occupations requiring more social skills is positively associated for unauthorized Mexicans accumulating social capital. Measures of human and financial capital are not associated with the probability of developing social capital.