“Two heads are better than one.” It’s a familiar expression—and one that businesses might want to heed. The authors’ study of 87 companies led by co-CEOs showed that those firms tended to generate better returns than did peer companies with a sole CEO. Successful power sharing at the top depends on multiple factors: strong commitment to the partnership by both leaders, complementary skill sets, clear responsibilities and decision rights, mechanisms for conflict resolution, the projection of unity, shared accountability, board support, and an exit strategy. The authors caution that the co-CEO model won’t work everywhere. But for large, multifaceted firms, those with agile-based management, and those engaged in technology transformations, it’s a promising option.