This paper introduces a new typology and associated measure of social and environmental mission integration by conceptually framing a feature of hybrid organizations—the degree of integration of their revenue model and social–environmental mission. The SEMI measure is illustrated using a hand-collected sample of 256 North American Certified B Corporations. We explore the heterogeneity of SEMI scores by identifying external-facing correlates and demonstrate non-congruence with Certified B Corporation’s audit results. Overall, our findings advance existing knowledge of these hybrid organizations and how (...) they balance their social–environmental missions with their economic objectives. (shrink)