Open Government Data (OGD) is increasingly an object of research. Whilst referred to as a platform problem, few studies examine the phenomenon using platform concepts. One challenge governments face is to establish thriving OGD ecosystems through appropriate platform governance. The governance of innovating complements on the demand side of platforms, such as services using OGD datasets by entrepreneurs for citizen users, is well studied in platform literature. However, understanding of the supply side and how third parties can be governed to help innovate platform core architecture, such a ministries sourcing quality datasets for OGD platforms, is lacking. In our preliminary study of emergent OGD platforms in Latin America, we construct a model extending concepts of boundary resources from the demand side to the supply side to expand our understanding of platform governance. In addition to contributing to platform governance theories, we improve our understanding of OGD platform ecosystem cultivation.