Voluntary standard and certification systems are proliferating in the United States and around the world. While the majority of certification research draws on case studies, we pursue a cross-sectional empirical analysis of an original database of 108 certifications operating in the United States. We analyse the rise and configuration of private regulatory initiatives, variations in programme breadth and focus, and variations in programme participation and oversight requirements. We highlight the predominance of international and multi-stakeholder initiatives in the United States. Our research identifies substantial convergence in the ecological and social priorities of certification programmes and even greater convergence in their assessment and oversight procedures. Statistical analysis helps explain the prevalence of multi-stakeholder initiatives, but we find no significant differences between these and industry-led initiatives in their foci or procedures. We argue that there is a standardization of certification norms and practices which may mask important programme differences.