Abstract: Certification programs--a form of private governance established by non-governmental organizations (NGOs) and businesses to advance responsible production practices--have emerged to make remarkable inroads in global markets and gain attention as a potentially important form of global governance. The talk explores two empirical differences in the rise and evolution of forest, coffee and fisheries certification programs: the time individual programs have taken to become global governors, and the number and variety of programs developing across different sectors. I will argue that to explain these differences, it is necessary to examine how collective action in markets is affected by the degree of market demand, particularly during the early stages of program development, and to combine analyses of collective action with a recognition of path dependence, since early choices, though not entirely irreversible, create lasting legacies. Once collective action efforts in a sector create a certification program, independent conditions and processes shape how individual programs internally evolve and whether, and in what form, new programs emerge.