IRS Publication 598: Tax on Unrelated Business Income

IRS Publication 598 explains how tax-exempt organizations calculate and pay federal income tax on unrelated business taxable income, or UBTI — the money they earn from regularly conducted commercial activities that don’t advance their exempt purpose. Publication 598 walks through which organizations are covered, the three-part test for identifying unrelated business income, the exclusions that keep most investment income tax-free, and how to file Form 990-T. The tax itself is only part of the picture: late filing brings penalties and interest, and if unrelated activity gets too large, a 501(c)(3) can lose its exemption altogether.

Which Organizations Are Covered

Almost every organization exempt under Internal Revenue Code Section 501 is subject to UBTI, including 501(c)(3) charities, 501(c)(4) social welfare groups, labor unions, trade associations, and fraternal organizations. The only exempt entities carved out are federal instrumentalities described in Section 501(c)(1).¹ State colleges and universities are covered too, as are corporations they wholly own. Qualified pension, profit-sharing, and stock bonus plan trusts under Section 401(a) also fall inside the UBTI rules, which matters most when those trusts hold partnership interests or debt-financed assets.²

The Three-Part Test

An activity generates UBTI only if it satisfies all three conditions below.³

It is a trade or business. Any activity carried on to produce income from selling goods or performing services qualifies. It doesn’t have to be a major part of what the organization does.
It is regularly carried on. The activity shows the frequency and continuity of a comparable taxable business. A one-off fundraiser generally fails this prong. A gift shop open year-round generally meets it.
It is not substantially related to the exempt purpose. The activity itself must meaningfully advance the mission, not just fund it. A university bookstore selling required course texts is substantially related. That same university renting its parking garage to weekday commuters is likely not.

Miss any one prong and the income falls outside UBTI, no matter how commercial the operation looks.

Activities and Income That Are Excluded

Congress wrote three broad exceptions into Section 513 that pull activities out of UBTI even when they meet the three-part test.⁴

Volunteer labor. If substantially all the work is done by unpaid volunteers, the income is not UBTI. There is no fixed percentage; the IRS compares volunteer hours to paid-staff hours across setup, operations, and cleanup. An all-volunteer car wash qualifies. One that hires a manager and cashiers probably doesn’t.⁵
Convenience of members. For 501(c)(3) organizations and government colleges or universities, activities run primarily for the convenience of members, students, patients, officers, or employees are excluded. Think campus cafeterias and hospital gift shops.⁶
Donated merchandise. Selling goods received substantially all as gifts or contributions is excluded. Charity thrift shops are the standard example.

Section 512 layers on a separate set of exclusions for passive investment income, so that exempt organizations can invest their operating funds and endowments without generating tax.⁷ Dividends, interest, and annuities are excluded, along with the deductions tied to earning them. Royalties are excluded regardless of how they are measured, including payments for the use of trademarks, copyrights, or patents. Rental income from real property is excluded, but rent tied to the tenant’s income or profits doesn’t qualify, and if a lease bundles personal property with real property, the whole rent loses the exclusion once more than 50 percent of it is attributable to the personal property. Rent set as a fixed percentage of gross receipts is still allowed. Gains and losses on sales of property are excluded unless the property is inventory or held primarily for sale to customers in the ordinary course of business.

There is also a research exclusion. Research performed for the federal government or its agencies is excluded. Research done by a college, university, or hospital is excluded regardless of the funder. And fundamental research whose results are freely available to the public is excluded for organizations whose primary purpose is that kind of research.⁶

Debt-Financed Property Overrides the Passive Exclusions

The passive-income exclusions come with a large asterisk. If the income-producing property was acquired or improved with borrowed money, Section 514 pulls part of that income back into UBTI as unrelated debt-financed income.⁸ The taxable slice is a ratio: average outstanding debt on the property during the year over the property’s average adjusted basis. Borrow $600,000 to buy a $1,000,000 building and roughly 60 percent of the rental income and 60 percent of the allowable deductions land inside UBTI. As the debt is paid down, the taxable share shrinks. Once the property is fully paid off, the rental exclusion applies in full.

Depreciation on debt-financed property has to be calculated using the straight-line method, even if the organization would otherwise use an accelerated method. This detail trips up organizations that copy general depreciation practice without checking the UBTI rules.

How To Calculate What You Owe

p>Start with gross income from the unrelated trade or business. Subtract the deductions directly connected to that activity: the ordinary and necessary business expenses, depreciation, and other costs a taxable business could claim. Every organization then takes a $1,000 specific deduction, so the first $1,000 of net unrelated income is effectively tax-free.⁷

Each Activity Sits in Its Own Silo

If you run more than one unrelated business, you cannot pool the results. Section 512(a)(6) requires UBTI to be computed separately for each activity, and no single activity’s UBTI can go below zero. Total UBTI is the sum of the separately computed positive amounts, with one $1,000 specific deduction applied at the end. A net operating loss from one unrelated business can only be carried forward against future income from that same business, not used against a different one.⁹ A profitable parking operation and a money-losing bookstore can’t cancel each other out.

Filing Form 990-T

Any exempt organization with gross income of $1,000 or more from an unrelated trade or business must file Form 990-T, the Exempt Organization Business Income Tax Return.¹⁰ The threshold is measured on gross income, so you still have to file even if deductions bring the tax to zero.

Deadlines

Exempt organizations taxed as corporations file by the 15th day of the fifth month after the tax year ends. For a calendar-year filer, that’s May 15.¹¹ Trusts generally follow the same fifth-month rule, but Section 401(a) pension plan trusts and Section 408(a) IRA trusts file by the 15th day of the fourth month, which is April 15 for calendar-year filers.¹² A deadline that lands on a weekend or legal holiday moves to the next business day. Filing Form 8868 gives you an automatic six-month extension of time to file, but not to pay; the estimated tax is still due on the original date.¹³

Rates and Estimated Payments

Exempt organizations taxed as corporations pay the flat 21 percent corporate rate on UBTI.¹⁴ Exempt trusts pay at the graduated trust rates, which climb to 37 percent on income above roughly $15,000. If you expect the year’s UBTI tax to reach $500 or more, you must make quarterly estimated payments; underpaying carries its own penalty on top of any late-payment penalty.¹⁵

Late Filing and Late Payment

Form 990-T is a tax return, not an information return, so missing the deadline pulls in the standard tax penalties. The failure-to-pay penalty is 0.5 percent of the unpaid tax per month or partial month, capped at 25 percent.¹⁶ Once the IRS issues a notice of intent to levy and 10 days pass without payment, that rate doubles to 1 percent per month. Interest also runs on unpaid tax from the original due date. For the first quarter of 2026 the underpayment rate is 7 percent, compounded daily, and the rate is reset each quarter.¹⁷ Interest compounds on top of penalties, so a delayed payment gets expensive faster than most organizations expect.

Public Disclosure of Form 990-T

501(c)(3) organizations must make their Form 990-T available for public inspection under Section 6104(d)(1)(A)(ii).¹⁸ Other exempt organizations — social welfare groups, trade associations, unions — are not required to disclose theirs. For affected charities, that means unrelated business details are visible to donors, journalists, and the general public.

Too Much Unrelated Income Can Cost You the Exemption

Paying UBTI is one problem. Losing tax-exempt status is a bigger one. The IRS has said plainly that earning too much unrelated business income can jeopardize a 501(c)(3)’s exemption.¹⁹ There is no numeric threshold. The test is whether the organization is still primarily engaged in activities that further its exempt purpose. If commercial activity dominates the organization’s time, resources, or revenue, the exemption is in jeopardy. Revocations of this kind usually follow years of gradual drift into commercial operations. Tracking the ratio of related to unrelated activity on an ongoing basis is the practical way to keep from getting there.

1
Office of the Law Revision Counsel. 26 U.S. Code 511 – Imposition of Tax on Unrelated Business Income of Charitable, Etc., Organizations
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Office of the Law Revision Counsel. 26 U.S. Code 401 – Qualified Pension, Profit-Sharing, and Stock Bonus Plans
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Internal Revenue Service. Unrelated Business Income Defined
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Office of the Law Revision Counsel. 26 USC 513 – Unrelated Trade or Business
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Internal Revenue Service. Volunteer Labor Exclusion From Unrelated Trade or Business
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Internal Revenue Service. Unrelated Business Income Tax Exceptions and Exclusions
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Office of the Law Revision Counsel. 26 USC 512 – Unrelated Business Taxable Income
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Office of the Law Revision Counsel. 26 USC 514 – Unrelated Debt-Financed Income
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Internal Revenue Service. FAQs – Carryback of NOLs by Certain Exempt Organizations
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Internal Revenue Service. Form 990-T – Exempt Organization Business Income Tax Return
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Internal Revenue Service. Return Due Dates for Exempt Organizations – Form 990-T (Corporations)
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Internal Revenue Service. Return Due Dates for Exempt Organizations – Form 990-T (Trusts)
13
Internal Revenue Service. About Form 8868, Application for Extension of Time To File an Exempt Organization Return or Excise Taxes Related to Employee Benefit Plans
14
Office of the Law Revision Counsel. 26 U.S. Code 11 – Tax Imposed
15
Internal Revenue Service. Estimated Tax: Unrelated Business Income
16
Office of the Law Revision Counsel. 26 U.S. Code 6651 – Failure To File Tax Return or To Pay Tax
17
Internal Revenue Service. Interest Rates Remain the Same for the First Quarter of 2026
18
Internal Revenue Service. Public Inspection and Disclosure of Form 990-T
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Internal Revenue Service. How To Lose Your 501(c)(3) Tax-Exempt Status (Without Really Trying)