Recent developments in health information technology (health IT) for health information exchange suggest that successful public-private collaborations should devote more attention to understanding the dynamics of collaboration. In the context of health information sharing for disability determination, this case study examines early instances of public-private interorganizational sharing of health information. The theoretical focus of the paper is on the construction of blended value propositions and their role in collaboration for health information exchange. For this purpose, we performed a case analysis of a prototype health IT application to be shared between the United States Social Security Administration and Beth Israel Deaconess Medical Center. The case analysis found that business, socio-organizational, and technical dynamics were operative during the planning and execution of the prototype. From a theoretical perspective, the case study provides insight into blended value propositions in terms of understanding and potentially predicting the success of newly established Health Information Exchanges (HIEs). The findings have implications for further development of collaboration value propositions and their evolution over the course of IT deployments for health information exchange.