Management of different types of partnerships plays a decisive role in company performance. Complex business ventures, such as those created to serve low-income populations, usually include both cross- and same-sector partnerships. However, the initial diversity featured in these alliance portfolios diminishes as companies take their ventures up to scale. This article develops theoretical propositions about the evolution and configuration patterns of portfolios that include both cross- and same-sector partnerships. Two longitudinal case studies serve to illustrate the theoretical framework developed for (...) alliance portfolios that include both types of partnerships. Companies that create such portfolios adopt partnership strategies that follow paths also identified in the evolution of portfolios only made up of partnerships with other private firms: i.e., an evolution from adapting to shaping and exploiting strategies. (shrink)