Alternative Investments in Your Solo 401k
How to put your retirement savings into real estate, crypto, private equity, and more — and the rules that keep it legal.
Beyond Stocks and Bonds
One of the most powerful — and least understood — features of a Solo 401k is that it isn't limited to the stock market. With the right plan, you can invest your retirement savings in real estate, cryptocurrency, private equity, precious metals, private lending, and other “alternative” assets, all while keeping the tax advantages of a 401k.
The catch: the free prototype plans offered by major brokerages (Fidelity, Schwab, E*TRADE, Vanguard) only let you buy publicly traded securities. To hold alternative assets you need a self-directed Solo 401k from a specialist provider. These plans charge setup and ongoing fees, but they unlock the full range of investments the IRS actually permits.
What You Can (and Can't) Hold
Commonly Allowed
- Rental real estate, raw land, and fix-and-flips
- Cryptocurrency (see our crypto in a Solo 401k guide)
- Private equity, startups, and LLC interests
- Precious metals (IRS-approved bullion)
- Private lending and promissory notes
- Tax liens and Delaware Statutory Trusts
Prohibited
- Collectibles (art, antiques, most coins, wine)
- Life insurance contracts
- Any prohibited transaction with a disqualified person (you, your spouse, your lineal family)
- Personal use of plan-owned property
Why You Need Checkbook Control
Alternative deals move fast. A good rental hits the market and you need earnest money today; a contractor needs paying this week. Checkbook control means your Solo 401k funds sit in a dedicated trust or bank account that you control as trustee — you can write a check or send a wire directly, without waiting on a custodian to approve each transaction.
This is the single biggest practical difference between a self-directed plan and a traditional brokerage account, and it's why real estate investors gravitate toward providers that offer an integrated trust checking account.
Choosing a Self-Directed Provider
The right provider depends on which assets you care about most. Two specialists come up again and again for self-directed Solo 401k plans:
- Rocket Dollar — a modern dashboard plus a trust checking account with unlimited fee-free transactions, and deep expertise in real estate. It also offers crypto through a direct Gemini integration. The trade-off is cost: it's pricier than the budget options.
- Nabers Group — allows nearly any asset class, supports self-custody (cold storage) crypto, and includes instant document preparation. A strong choice if you want maximum flexibility and the lowest ongoing cost.
Want the full picture, including the free brokerage options for comparison? See our Solo 401k provider comparison.
Know the Rules Before You Invest
Self-direction comes with responsibility. Two pitfalls deserve special attention:
- Prohibited transactions. You can't buy an asset you already own, rent a plan-owned property to family, or otherwise benefit personally. A single prohibited transaction can disqualify the entire plan.
- UBIT / UDFI. Income from debt-financed real estate or an actively operated business inside the plan can be taxable. Model this with a tax professional before using leverage.
Bottom line: alternative investments can supercharge a Solo 401k, but the margin for error is smaller than with index funds. A provider with strong compliance support is worth the fee.
Frequently Asked Questions
Can a Solo 401k invest in real estate?
Yes. A self-directed Solo 401k can own rental property, raw land, and fix-and-flip projects. The property is titled in the name of the 401k (or its trust), all income flows back into the plan tax-deferred (or tax-free in a Roth), and all expenses must be paid from the plan. You cannot use the property personally or rent it to disqualified persons.
What investments are not allowed in a Solo 401k?
The IRS prohibits a Solo 401k from holding collectibles (art, antiques, most coins, alcoholic beverages) and life insurance contracts. Beyond those, the bigger risk is prohibited transactions — any deal that benefits you or another disqualified person personally, such as buying a property you already own or living in a rental owned by your plan.
What is checkbook control?
Checkbook control means your Solo 401k funds sit in a dedicated bank or trust account that you, as trustee, can write checks from directly. It lets you act on a deal immediately — earnest money, repairs, a wire to a crypto exchange — without waiting on a custodian to process each transaction.
Do free brokerage Solo 401k plans allow alternative investments?
No. The free prototype plans from Fidelity, Schwab, E*TRADE, and Vanguard restrict you to publicly traded securities (stocks, bonds, ETFs, mutual funds). To hold real estate, crypto, or private equity you need a self-directed plan from a specialist provider, which charges setup and ongoing fees in exchange for that flexibility.
What is UBIT and when does it apply?
Unrelated Business Income Tax (UBIT) can apply when a retirement account earns income from a business it actively operates or from real estate purchased with debt financing (UDFI). For example, rental income attributable to a non-recourse mortgage may be taxable to the plan. Many leveraged real estate investors still come out ahead, but you should model UBIT with a tax professional before using debt inside your plan.
Find a Self-Directed Solo 401k Provider
Compare providers that support real estate, crypto, and other alternative investments side by side.
Compare Solo 401k Providers