If you're making money from a side hustle or running your own business, you could be missing out on one of the most powerful tax and wealth-building strategies available to entrepreneurs: the Solo 401(k). I'm talking about substantial tax deductions, Roth contributions, self-directed investing, asset protection, and even the ability to borrow from your retirement account. And you don't need a large company or a team of employees to take advantage of it. Whether you're consulting after hours, selling products online, or running a full-time business, a Solo 401(k) deserves a serious look.
The Solo 401(k), also called an Individual 401(k), is designed for self-employed individuals and business owners who don't have employees requiring coverage under the plan, other than an eligible spouse. You don't have to run a large operation or even work in your business full-time. A legitimate side hustle can qualify, provided you have qualifying earned income and meet the employee eligibility requirements.
Think about the possibilities:
Even if you have a regular W-2 job, your separate business can potentially qualify for its own Solo 401(k). And what about rental property owners? Rental income generally doesn't qualify as earned income for retirement plan purposes. However, a legitimate property management business that earns compensation for actual services can potentially create an opportunity to establish a Solo 401(k). I call this the side-door Solo 401(k) strategy.
Now that you understand who can qualify, let's look at why I recommend this retirement plan so often.
The Solo 401(k) allows you to contribute to retirement as both the employee and the employer. That's a tremendous advantage over relying solely on an IRA. For 2026, the basic employee deferral limit is $24,500, with additional catch-up contributions available for eligible individuals age 50 and older. Your business can also make employer contributions, subject to compensation requirements and annual limits.
The general 2026 defined contribution limit is $72,000 before eligible catch-up contributions. That's a significant amount of money you can potentially put toward retirement in a single year. And if you're making traditional pretax contributions, those contributions can help reduce your current tax liability. Think about the difference between contributing a few thousand dollars to an IRA and potentially putting tens of thousands of dollars into a Solo 401(k). Over ten or twenty years, that difference can be substantial.
Of course, your actual contribution limit depends on your business income, compensation, age, and other retirement plans. In Part 2, I'll walk through the contribution calculations and how to maximize what you can put away.
A Solo 401(k) gives you flexibility in how your retirement contributions are taxed. Traditional contributions can provide a current tax benefit, while Roth contributions are made with after-tax dollars and can provide tax-free qualified withdrawals in retirement. But the Solo 401(k) can offer another opportunity: the mega backdoor Roth strategy.
With the right plan provisions, eligible business owners can potentially make additional after-tax contributions and convert those dollars to Roth. This creates opportunities to build a substantial Roth retirement account without being restricted by the income limits that apply to direct Roth IRA contributions. You can also potentially combine traditional and Roth strategies, depending on your current tax bracket and long-term financial goals.
I love this flexibility because your tax strategy should change as your income and financial situation change. There may be years when taking a deduction makes the most sense, and other years when building tax-free retirement wealth is the better move. The important thing is having those options available.
Here's something that surprises a lot of business owners: You don't necessarily have to choose between your employer's retirement plan and a Solo 401(k). If you have a regular W-2 job and operate a qualifying business on the side, you can potentially participate in both retirement plans. You may also be eligible to contribute to a traditional or Roth IRA.
This opens the door to a strategy I call Match and Out. If your day-job employer offers a 401(k) match, I generally want you taking advantage of that benefit. It's additional compensation toward your retirement, and there's no reason to leave it on the table. Then, depending on your income and contribution limits, you can direct additional eligible retirement contributions into your Solo 401(k), where you may have greater investment flexibility and control.
The employee salary deferral limit is generally shared across your 401(k) plans, so you can't simply double your personal deferrals. However, employer contributions through your separate business can create additional retirement savings opportunities. And yes, you can potentially have an IRA alongside those plans, subject to the applicable income and contribution rules.
Why limit yourself to one retirement account when you can coordinate multiple accounts to build more wealth?
This is one of my favorite benefits of the Solo 401(k). With a properly structured self-directed Solo 401(k), you aren't necessarily limited to stocks, bonds, mutual funds, and whatever investment menu a brokerage company puts in front of you.
You can potentially invest in alternative assets such as:
Now, I have nothing against the stock market. But I also believe entrepreneurs should have the opportunity to invest in assets they know and understand. Maybe you've spent your career in real estate. Maybe you understand private lending or have experience evaluating private businesses. A self-directed Solo 401(k) can give you the flexibility to explore those opportunities with retirement dollars.
Of course, alternative investments come with risks, and prohibited transaction rules restrict certain investments and dealings with disqualified persons. But the ability to choose from a broader range of investments is a significant advantage for experienced entrepreneurs.
A self-directed Solo 401(k) can also give you something many traditional retirement accounts don't: checkbook control. With the proper plan structure, you can serve as trustee of your Solo 401(k) and exercise direct control over permitted investments through the plan's bank account. That means you may be able to act on investment opportunities without waiting for a third-party custodian to process every transaction.
For example, if your Solo 401(k) is investing in a private lending opportunity or purchasing an eligible investment property, having checkbook control can make the process more efficient. And for entrepreneurs who are used to making decisions and managing investments themselves, that flexibility can be incredibly valuable.
Now, checkbook control doesn't mean you can use retirement funds however you please. The money still belongs to the retirement plan, and you must follow all applicable fiduciary and prohibited transaction rules. But when it's structured and managed properly, you get greater control over how your retirement dollars are invested.
Unlike an IRA, a Solo 401(k) can allow you to borrow against your retirement account. Generally, if your plan permits participant loans, you may be able to borrow up to the lesser of $50,000 or 50% of your vested account balance, subject to certain exceptions and adjustments. That's a valuable option for a business owner who needs access to capital without immediately taking a taxable retirement distribution.
Maybe you're dealing with an unexpected expense, trying to eliminate high-interest debt, or need temporary liquidity. A properly structured participant loan can give you access to funds while allowing you to repay the principal and interest back into your retirement account.
But remember, this is still a real loan. It has repayment requirements, and failure to follow them can result in taxes and potential penalties. I don't recommend borrowing from retirement accounts casually. However, having the option available can provide financial flexibility that an IRA simply doesn't offer.
Already have retirement savings sitting in an old employer 401(k) or traditional IRA? Depending on the account type and plan provisions, you may be able to roll eligible retirement funds into your Solo 401(k). That means you can potentially consolidate retirement accounts and bring more of your existing savings under one retirement strategy.
This can be particularly attractive if your old retirement accounts are sitting in conventional brokerage investments and you'd prefer to explore self-directed opportunities. It can also simplify your retirement planning by reducing the number of separate accounts you're managing.
Eligible rollovers may include funds from former employer plans, traditional IRAs, SEP IRAs, and certain other retirement accounts. Roth IRAs cannot be rolled into a Solo 401(k). And here's another planning benefit: Moving eligible pretax IRA funds into a 401(k) can sometimes help with the pro-rata rules when implementing a separate backdoor Roth IRA strategy.
The flexibility to consolidate and reposition existing retirement assets is another reason the Solo 401(k) deserves serious consideration.
If you're an entrepreneur, asset protection should always be part of your financial strategy. You're building a business, signing contracts, taking on financial obligations, and potentially exposing yourself to lawsuits or creditor claims. A properly established Solo 401(k) can provide meaningful protection for retirement assets under applicable federal and state laws. That's an important advantage over simply accumulating investments in your personal name.
The specific protections depend on your state, the type of retirement plan, and the nature of the creditor claim. Owner-only plans don't always receive the same protections as larger employer-sponsored plans governed by ERISA. There are also exceptions, including certain tax obligations and domestic relations claims.
But the larger point is that retirement planning and asset protection should work together. I want business owners building wealth in structures that help protect what they've worked so hard to accumulate.
A Solo 401(k) can also create opportunities to build retirement wealth as a family. If your spouse legitimately works in your business and receives qualifying compensation, they may be eligible to participate in the plan and make their own retirement contributions. That can significantly increase the amount your household puts away for retirement.
And beyond your lifetime, your Solo 401(k) can pass to designated beneficiaries, subject to the applicable inheritance and distribution rules. Depending on the beneficiary and the account's tax treatment, inherited retirement funds can continue receiving certain tax advantages for a period of time. Roth assets can be particularly valuable because qualified distributions are generally income-tax-free.
Now, don't overlook the importance of beneficiary designations. Your retirement plan should coordinate with your estate plan, your trust, and your family's long-term financial goals. Building wealth is important. Making sure that wealth passes to the right people under the right structure is just as important.
Here's a benefit that makes the Solo 401(k) even more attractive: Certain businesses can receive tax incentives for establishing a retirement plan. Ordinary and necessary expenses associated with establishing and administering an eligible retirement plan may qualify as business deductions, subject to applicable rules. Some eligible small employers can also qualify for retirement plan startup tax credits, including incentives related to qualifying automatic enrollment arrangements.
For example, Internal Revenue Code Section 45T provides a potential $500 annual credit for up to three years for eligible employers that establish a qualifying automatic contribution arrangement. That's a potential $1,500 in tax credits.
However, these credits have specific eligibility requirements, and not every owner-only Solo 401(k) qualifies. In particular, some credits require eligible non-highly compensated employees or other conditions that an owner-only business may not satisfy. So don't assume the government will automatically pay you to open a Solo 401(k). Have your eligibility reviewed before factoring a credit into your decision.
Even without a startup credit, the potential retirement contribution deductions and long-term tax advantages can make this plan extremely valuable.
The Solo 401(k) brings together ten benefits that can make a tremendous difference for small business owners: substantial retirement contributions, Roth opportunities, multiple retirement accounts, self-directed investing, checkbook control, participant loans, rollovers, asset protection, family wealth planning, and potential tax incentives.
But having access to these benefits is only the beginning. You need a retirement strategy that works with your business structure, your income, and your long-term financial goals. If you're running a business or earning self-employment income and haven't explored a Solo 401(k), Book a Comprehensive Tax and Business Consultation with my law firm, KKOS Lawyers, and find out how to take advantage of the opportunities available to you.
Ready to understand the next steps? Read Part 2: How to Set Up, Invest, and Maintain Your Solo 401(k) for the contribution calculations, plan setup requirements, investment procedures, and ongoing compliance rules.
Don't wait another year to put one of the most powerful retirement tools for business owners to work.