Which fund structures generate taxable income inside a retirement plan?
Two separate mechanisms create exposure, and they operate independently of each other. The first is debt-financed income: when a fund borrows at the fund level, the portion of income attributable to that leverage becomes Unrelated Debt-Financed Income. The second is active business income, which arises when a fund is structured as a partnership or LLC and the underlying business is an active trade or business rather than a passive investment. That income passes through to your plan as Unrelated Business Taxable Income.
A corporate structure sidesteps both. When an entity pays tax on its own income and distributes what remains as dividends, that income is passive under IRC Section 512(b), no matter how the underlying business operates.
Which fund types most commonly trigger this?
Leveraged real estate syndications and leveraged note funds are the two most frequent sources of exposure. In a syndication, the fund's mortgage financing produces debt-financed income on the leveraged share of returns, taxable to an IRA investor.
Plan type changes the outcome here. A Solo 401(k) holds an exemption from UDFI on debt used to acquire real property, which shelters the same leveraged syndication that would be taxable inside an IRA.
A leveraged note fund is a different case. The Solo 401(k) exemption is specific to real estate acquisition debt, and a fund borrowing to acquire more notes doesn't qualify. Both plan types owe tax on the debt-financed portion of that fund's income.
Which structures generally stay passive?
REITs avoid the question entirely. The entity pays tax on its own income and distributes dividends, so what reaches your plan is passive by classification rather than by what the REIT happens to own.
Private equity funds reach a similar result by a different route. The fund itself is typically a partnership or LLC, not a corporation, but the portfolio companies it invests in are usually C corporations. Those companies pay tax at the corporate level, and what flows up through the fund to your plan arrives as dividend income already taxed. A private equity fund holding pass-through operating companies instead would pass active business income through to your plan, which is possible but far less common. Each fund's actual holdings determine the answer, so confirm the structure rather than assuming it from the asset class.
What should a sponsor be able to tell you about this?
A sponsor cannot advise you on what UDFI or UBIT exposure means for your specific tax situation. That boundary is correct, and it points you to your own CPA or attorney rather than reflecting poorly on the sponsor.
Whether the offering is structured to generate either one is a different question. Does the fund use leverage? Is the underlying entity taxed as a corporation or a pass-through? Both are facts about the deal, and a sponsor should answer them plainly. A sponsor who deflects behind "we can't advise" is withholding structural information you need, to the point where you would have to pay a CPA or attorney to read the prospectus and work it out. That is a diligence signal worth acting on, and sponsor evaluation should surface it well before deal terms become the focus.
Frequently Asked Questions
Does UBIT apply the same way to an IRA and a Solo 401(k)?
Not always. Both owe tax on active business income the same way. The difference is the Solo 401(k)'s exemption on real estate acquisition debt, which shelters a leveraged real estate syndication that an IRA would owe tax on. A leveraged note fund falls outside that exemption and is taxed the same for both.
If a fund uses some leverage, does all of its income become taxable?
No. Tax applies only to the share of income attributable to borrowed capital. The portion funded by your plan's own money stays sheltered, and allowable deductions are scaled to the same proportion.
Is interest income from a note fund automatically UBTI?
No. Interest is passive income under IRC Section 512(b) regardless of its source. Exposure in a note fund comes from leverage at the fund level, not from the interest the notes produce.
Can a sponsor refuse to tell me whether their fund uses leverage?
They can decline, and that answer tells you something. Leverage is a structural fact about the offering, not investment advice, and a sponsor unwilling to state it plainly is not a counterparty worth your plan's capital.
What happens if my plan owes this tax?
The plan is the taxpayer, not you personally, and the tax is paid from plan funds. Reporting runs through Form 990-T, prepared by a CPA experienced with tax-exempt entity returns.
Next Steps
Before committing capital to any fund offering, ask the sponsor two questions: does the fund use leverage, and how is the underlying entity taxed. Those answers determine your plan's exposure. To confirm which plan structure best fits a leveraged real estate strategy, use the Plan Finder.