We examine whether financial constraints impede these types of start-ups by exploiting lottery wins as exogenous wealth shocks. We find that lottery-win magnitude increases winners’ subsequent incorporation, implying that entrepreneurs face financial constraints, but not business registration, implying that financial constraints do not bind as much for the self-employed. Our results, that financial constraints bind for incorporations among men, for serial entrepreneurs, during economic booms, and in neighborhoods without local lenders, are important for understanding the financial impediments to entrepreneurial start-ups.