Recognizing the need for effective cyber risk management processes across the supply chain, the AICPA issued a new SOC in March 2020 for assuring cyber supply chain risk management (C-SCRM) processes. This study examines supply chain relationship factors and cyber risk issues to better understand the demand for C-SCRM assurance. Resource-Advantage Theory of Competition provides the conceptual foundation for assessing the dual drivers of relationship building and cyber risk management on demand for assurance. We use a field survey to collect data from 205 professionals enabling evaluation of the complex relationships in the theoretical model. Results support all hypotheses, provide satisfactory model fit, and support the underlying theory. Trust and cyber supply chain risk both positively influence demand for assurance over C-SCRM processes. This study expands the literature on cyber assurance by auditors and elaborates on overall supply chain processes that help drive value from auditors providing such assurance.