The global Open Access eBook Usage (OAeBU) Data Trust effort has worked with stakeholders to document both the usage data supply chain for OA books and specific use cases detailing how this data is used across libraries, publishers, publishing platforms and services. This information has clarified the role of the data trust, allowing its stakeholders to work through defining usage data governance mechanisms, core data trust principles, and ethical guidelines for the aggregation and display of OA book impact analytics. This poster will summarize past and future research for the emergent OA Book Usage Data Trust, highlighting how foundational data supply chain, use case, and legal research informed open-source software development, governance mechanism design, and sustainability modeling. It will also showcase and seek feedback on emerging community-developed principles to provide and sustain trust among those sharing and relying on the exchanged metrics. About the Open Access eBook Usage (OAeBU) Data Trust Conceived in 2015 at the Scholarly Communications Institute, this effort has grown into an international effort to develop and pilot a global data trust for OA monograph usage data (www.oabookusage.org). Supported by The Andrew W. Mellon Foundation, the project is now in its third phase, actively developing community governance mechanisms to support trusted, public/private OA book usage data exchange at scale.