Even though an organization is recognized as tax exempt, it still may be liable for tax on its unrelated business income. For most organizations, unrelated business income is income from a trade or business, regularly carried on, that is not substantially related to the charitable, educational, or other purpose that is the basis of the organization’s exemption. An exempt organization that has $1,000 or more of gross income from an unrelated business must file Form 990-TPDF. An organization must pay estimated tax if it expects its tax for the year to be $500 or more.
Nonprofit Unrelated Business Income Explained – Foundation Group