Alliances are an important tool for building and maintaining competitiveness in today's market. However, both research and practice often view collaborations as individual occurrences, without thoroughly analyzing potential synergies and conflicts. To determine this portfolio effect, Marcus Lorenz develops a conceptual framework that allows for a comprehensive analysis of companies' cooperative activities. The focus is on the configuration of the alliance portfolio. Through a longitudinal analysis of 60 leading companies, he derives practical recommendations. The study thus provides important insights for making collaborations accessible to active and holistic management.