GuideStar's National Database of Nonprofit Organizations offers users a wealth of information about American nonprofit organizations. It is the nation's most comprehensive source of data about U.S. nonprofits the Internal Revenue Service has declared tax exempt under Section 501(c) of the U.S. Tax Code.
The breadth and depth of the GuideStar database are unmatched. Most watchdog groups list a few hundred organizations, and state charities officials and nonprofit associations focus on the organizations in their respective states and regions. In contrast, the GuideStar database contains information about every public charity, private foundation, and other 501(c) organizations to which contributions may be tax deductible, more than 850,000 nonprofits in all. (For a discussion of the differences between private foundations and public charities, see "Just What Are Public Charities and Private Foundations, Anyway?")
Small organizations stand on equal footing with large nonprofits in the GuideStar database, and information on rural groups is as accessible as data on urban organizations. In addition to financial data, the GuideStar database contains information about the missions and programs of thousands of nonprofits.
GuideStar obtains information on the organizations in the database from three main sources: the IRS Business Master File (BMF), IRS Forms 990 and 990-EZ, and the nonprofits themselves. The source of the data on a specific nonprofit organization determines the completeness of that nonprofit's GuideStar Report.