Today's startups are a major source of innovation, as they employ emerging technologies to invent products and reinvent business models. Corporations that embrace an open innovation strategy increasingly look to startups as a source of external innovation. Corporate accelerators offer a potent approach to nurturing innovations from entrepreneurial ventures. However, the vast differences between corporations and startups make collaboration a challenge. Corporate accelerators need to be designed effectively to add value for startups and create innovation benefits for the company. Based on information obtained during interviews with managers and participants of corporate accelerators (n=40), managers receive a framework and strategies for designing corporate accelerators. To leverage startups' innovation and to make corporate accelerators an effective part of a firm's overall innovation strategy, managers need to systematically and thoughtfully consider the design dimensions of proposition, process, people, and place.