Self-Directed IRA and Solo 401(k)

How it works

A self-directed IRA is not a separate kind of account under the Code. It is an ordinary IRA under Section 408, or an ordinary qualified plan, held at a custodian or trustee willing to administer assets that are not publicly traded. The label describes the custodian rather than the tax law.

What an account like that typically holds is rental real estate, raw land, private mortgage notes, LLC or LP interests, private company equity, and precious-metals bullion within the narrow opening Section 408(m) leaves for it.

The tax treatment is the ordinary treatment of the account type. Contributions may be deductible in a traditional account or after-tax in a Roth; income and growth inside the account compound tax-deferred, or tax-free in a Roth under Section 408A. Self-direction does not improve that shelter. It only widens what the shelter can sit on.

The two structures

In a custodial self-directed IRA every transaction routes through the custodian, who signs, holds title, and processes the funds.

In the checkbook variant, the IRA owns 100 percent of a single-member LLC, the account owner serves as that LLC's uncompensated manager, and he writes checks directly. It is faster and cheaper per transaction, and it moves the prohibited-transaction tripwires off the custodian's desk and onto his own. That is the trade being made.

The solo 401(k) version

A one-participant 401(k) for an owner-only business can hold the same alternative assets, and it carries two structural advantages over an IRA. It is generally exempt from unrelated debt-financed income on debt-financed real property under the qualified organization exception in Section 514(c)(9), which reaches qualified plans and does not reach IRAs. And its contribution ceilings are higher, because it admits an elective deferral and an employer contribution rather than one annual limit.

Choosing the plan and self-directing it are separate decisions, since self-direction is a property of the custodian rather than of the account type.

What gets taxed inside the account

Rent from real property is normally excluded from unrelated business taxable income under Section 512(b)(3), and gain on a sale under Section 512(b)(5). Section 512(b)(4) removes both exclusions to the extent the property is debt-financed, cross-referencing Section 514. That is unrelated debt-financed income.

Section 514(a)(1) sets a debt/basis percentage: average acquisition indebtedness, as Section 514(c)(1) defines it, divided by average adjusted basis. That percentage of the income is pulled into unrelated business taxable income, reduced by the same percentage of the directly connected deductions such as depreciation and interest, and then by the $1,000 specific deduction of Section 512(b)(12). As the loan amortizes the percentage falls, and the taxed share with it.

What remains is taxed inside the account at trust rates. Section 511(b)(1) imposes the tax computed as provided in Section 1(e), and that schedule is sharply compressed. For 2026 it runs 10% to $3,300, 24% to $11,700, and 35% to $16,000, with 37% applying above $16,000.

Debt is not the only route to a taxable dollar inside the account. If the account holds an interest in an active operating business, its share of the operating income is unrelated business taxable income under Sections 512(a)(1) and 513 with no debt anywhere in the structure, because an unrelated trade or business is neither passive rent nor capital gain, and the exclusions in Section 512(b)(3) and (b)(5) do not reach it.

What this is worth in Florida

Florida has no individual income tax and does not tax pass-through income at the personal level, so a disqualification or an unrelated business income tax bill is a federal cost only. There is no state relief to offset it and no state addition on top of it.

One Florida protection does not travel with the asset. Homestead protection attaches to a natural person's homestead, and property held in a self-directed IRA is owned by the IRA rather than by the individual, so the protection does not extend to it.

Who this applies to

The eligibility question is smaller than people expect. Anyone with an IRA or an eligible plan can self-direct one, and the gate is finding a custodian willing to administer alternative assets rather than qualifying under a rule.

What filters is how the account gets funded and what it may hold.

• The funding route. An IRA's annual contribution is a fixed dollar limit adjusted for inflation each year, with a catch-up amount from age 50. Against the price of a property that is small, so a purchase of any size is generally funded from a balance moved in rather than from a year of contributions. A solo 401(k)'s total annual additions, an elective deferral plus an employer contribution, are far higher.
• The Roth gate. A new Roth IRA contribution phases out across a modified adjusted gross income range that depends on filing status and is adjusted each year. That gate governs new contributions, not what a balance already inside a Roth account may hold.
• Collectibles are out. Art, antiques, gems, most coins, and alcoholic beverages are deemed distributed at cost the moment the account acquires them, under Section 408(m)(1). The exception in Section 408(m)(3) is narrow: gold, silver, and platinum coins minted by the United States, and bullion meeting exchange fineness standards, held by the trustee.
• Life insurance is out. An IRA may not hold a life insurance contract, under Section 408(a)(3).

What it requires

Each of these has to hold for as long as the account holds the asset. A prohibited transaction in year four disqualifies the account in year four, and nothing about years one through three protects it.

• A qualified trustee, and title in the account's name. An IRA must have a bank or an IRS-approved nonbank trustee under Sections 408(a)(2) and 408(n). The custodian holds title in the name of the IRA, and the owner never takes personal title to anything the account buys.
• Every dollar in and out is the account's. The account pays all cash to close, all repairs, and all carrying costs, and all rent, interest, and sale proceeds come back to it. There is no commingling in either direction: an owner who covers a plumbing bill from his personal checking account has broken this.
• Non-recourse leverage only. A recourse loan personally guaranteed by the owner is a prohibited extension of credit under Section 4975(c)(1)(B). Non-recourse structuring keeps the loan lawful without keeping the income sheltered, because non-recourse debt still produces unrelated debt-financed income for an IRA.
• No compensation to the owner out of the structure. In the checkbook variant the owner manages the LLC without pay. Taking a management fee or a salary is fiduciary self-dealing under Section 4975(c)(1)(E).
• A Form 990-T where the account has taxable income. The return is required when the account's gross unrelated business income is $1,000 or more. That threshold matches the specific deduction in Section 512(b)(12), which is also $1,000. The account files through its custodian under its own EIN and pays from account funds; the owner reports none of it on his personal return.

What you need to document

The burden runs the wrong way for the taxpayer here. On a prohibited-transaction question it is on the account owner to show the transaction was not prohibited, so the file has to establish a negative, and it has to be built while the facts are happening rather than reconstructed afterward.

Custodian statements and closing documents titled to the account

Every instrument naming the account rather than the owner as the party: the closing statement, the deed, the note.

A dedicated bank account

A separate account for the IRA or the IRA-owned LLC, through which every receipt and every disbursement runs. A single payment made from or into a personal account is what commingling looks like in the record.

Third-party property management

An arm's-length management contract wherever the owner cannot service the asset himself, showing that the services were furnished by someone who is not a disqualified person.

Evidence that pricing was arm's length

Board-minute-style records of how each price and rate was set, so the terms can be shown to have come from outside the account.

A memorandum that no disqualified person uses or services the asset

A written confirmation, kept current, that no disqualified person occupies the property, works on it, or is paid by it.

Where it goes wrong

The dominant failure mode is not a proportionate penalty. It is the whole account.

Under Section 408(e)(2)(A), if the owner or a beneficiary engages in any prohibited transaction described in Section 4975, the IRA stops being an IRA as of the first day of that taxable year. The entire fair market value is deemed distributed on that date: ordinary income in a traditional account, plus the 10% additional tax on early distributions under Section 72(t) if the owner is under 59 1/2. There is no de minimis threshold and no self-correction for an IRA prohibited transaction.

The 15% initial and 100% second-tier excise taxes in Section 4975(a) and (b) are the penalty structure for a qualified plan. For an IRA, Section 4975(c)(3) displaces them with the loss-of-status rule instead, so the same act costs an excise tax in a qualified plan and the account itself in an IRA.

Who counts as a disqualified person

Section 4975(e)(2) draws the set: the account owner, who is a fiduciary of it, the owner's spouse, ancestors, lineal descendants and the spouses of those descendants under Section 4975(e)(6), any entity 50% or more owned by those persons, and fiduciaries and service providers to the account.

Section 4975(e)(6) omits siblings from that family definition. It is a narrow lane and a real one, and it is worth using only with caution, because sitting outside the family list is not the same as sitting outside Section 4975(e)(2) altogether.

The six prohibited transactions

Section 4975(c)(1) lists them by paragraph.

The mistakes that disqualify an account

• Using the property. The owner, his children, or his parents staying in it, vacationing at it, or doing sweat-equity repair work on it. That is personal use and furnishing services, under paragraphs (C) and (D).
• Paying for it personally. An expense covered out of pocket, or rent deposited into a personal account. Both are commingling and an indirect benefit.
• Trading with the account. Buying a property the owner or another disqualified person already owns, or selling the account's property to one, under paragraph (A).
• Guaranteeing the loan. Personal guarantees of IRA-owned LLC debt have been held to be prohibited extensions of credit under paragraph (B). Courts read Section 4975 strictly and refuse equitable relief, so assume there is no good-faith exception.
• Taking a fee. A management fee or a salary out of the IRA-owned LLC is self-dealing under paragraph (E).

The failure that is only expensive

Unrelated business income tax and unrelated debt-financed income are a cost rather than a disqualifier. Failing to file Form 990-T and pay when gross unrelated business income is $1,000 or more is an unpaid-tax and penalty problem inside the account, not a Section 4975 violation. Ignoring a known obligation of that kind is nonetheless an audit flag.

A situation where this comes up

The version I see is an owner with a meaningful retirement balance and a particular Central Florida rental in mind, who has been told his account can buy it. That part is true.

Two questions decide whether it should, and both are answerable before anything is signed. The first is whether the purchase will be leveraged. In an IRA, a non-recourse mortgage makes the debt-financed fraction of the rent taxable inside the account every year at trust rates, with a Form 990-T due once gross unrelated business income reaches $1,000. Section 514(c)(9) removes that for debt-financed real property held in a solo 401(k), which is the single strongest reason for an owner-only business to use one rather than a self-directed IRA for leveraged real estate.

The second is who is going to touch the property. If the answer involves the owner swinging a hammer on a weekend, or a son living in the unit at a friendly rent, the structure is wrong for that person, and the consequence is not a disallowed deduction. It is the account.

None of this is an argument against the structure. It is an argument for settling the vehicle, the leverage, and the boundary before the first wire, because the version of this that goes wrong does not go a little wrong.