For most organizations, an activity is an unrelated business (and subject to unrelated business income tax) if it meets three requirements: It is a trade or business, It is regularly carried on, and It is not substantially related to furthering the exempt purpose of the organization. There are, however, a number of modifications, exclusions, and exceptions to the general definition of unrelated business income. Additional information Publication 598, Tax on Unrelated Business Income of Exempt Organizations PDF Exempt organizations continuing professional education text article (1999) PDF
