We compare individuals presently employed either at a university, or at a firm from an R&D-intensive sector, and analyze which of their personal-specific and employer-specific characteristics are related to their choice to leave their present employer for an own startup. Our data set combines the population of Danish employees with their present employers. We focus on persons who at least hold a Bachelor's degree in engineering, sciences and health and track them over 2001-2012. We show that (i) there are overall few differences between the characteristics of university and corporate startup entrepreneurs, (ii) common factors associated with startup activity of both university and corporate employees are education, top management team membership, previous job mobility and being male, (iii) it is primarily human capital-related characteristics that are related to startup choice of university employees while (iv) the characteristics of the present workplace are the foremost factors of entrepreneurial activity by corporate employees.