The Private Foundations Study Private foundations organized for charitable purposes are exempt from income taxes. They are differentiated from tax-exempt public charities by their narrow bases of control and financial support. Data are compiled from Form 990-PF, and are available for the following types of organizations: Operating Foundations, Nonoperating Foundations, and Section 4947(a)(1) Nonexempt Charitable Trusts. This page provides additional information about data produced in SOI's Private Foundations Study. Please click on a link below to get started. • Selected Terms and Concepts • Current and Prior Revisions of Form 990-PF • Data Sources and Limitations Please visit the Domestic Private Foundation and Charitable Trust Statistics page for data tables, articles, and publicly available microdata. The IRS Tax Information for Private Foundations page provides additional information concerning private foundations.