The nonprofit charitable sector owns more than $3.3 trillion of assets – resources used in the provision of goods and services. Here, we describe the various types of assets used by nonprofits, and how these assets are distributed among industries. We then outline theories about asset composition in the nonprofit sector; as the sector changes and increasingly reflects the entrepreneurial spirit of social enterprise, theories about asset composition also are changing. Nonprofit organizations have unique asset ownership issues. Specifically, nonprofits own privileged assets – those resources that nonprofits might be unable to alter; restricted assets – those resources that donors limit to use or time; and endowments – those investments that are expected to generate further revenues for the nonprofit. Research on nonprofit assets is limited by both positive and normative elements. On the one hand, data are of limited availability; on the other, asset accumulation in nonprofits is widely viewed with skepticism.