If your self-employment income is steady, a Solo 401(k) usually beats a SEP IRA for a self-employed NRI: more room to save, plus a Roth option and a loan feature. A SEP IRA wins on simplicity, and both cap at $72,000 for 2026.
What is a Solo 401(k)?
A Solo 401(k), also called a one-participant, individual, or self-employed 401(k), is a standard 401(k) built for a business with no employees other than you and your spouse.
You play two roles: the employee, who defers part of their income, and the employer, who adds a profit-sharing contribution.
Read more on how a 401(k) works for US-based NRIs if the basics are new to you.
That dual role is what lets a Solo 401(k) hold more money than a SEP IRA at the same income, and it's the main reason self-employed people pick it.
What is a SEP IRA?
A SEP IRA (Simplified Employee Pension) is a type of traditional IRA that a business funds entirely through employer contributions. There's no employee deferral and no separate plan document to draft.
You open one with a single IRS form and a regular IRA account at almost any brokerage.
A SEP IRA works for a sole proprietor with no staff just as well as it does for a business with a dozen employees.
That's true as long as you contribute the same percentage of pay to everyone eligible.
| Feature | Solo 401(k) | SEP IRA |
|---|---|---|
| Who can open one | Self-employed with no full-time common-law employees other than a spouse | Self-employed or a business of any size, including one with employees |
| Employee deferral, 2026 | Up to $24,500, or $32,500 at age 50+, or $35,750 at ages 60-63 | Not available. Employer contributions only |
| Employer contribution formula | About 25% of W-2 wages for an S-corp owner, or about 20% of net self-employment earnings for a sole proprietor | Same formula: about 25% of compensation, or about 20% of net self-employment earnings |
| Total contribution cap, 2026 | $72,000, or up to $83,250 with the enhanced 60-63 catch-up | $72,000. No catch-up allowed at any age |
| Catch-up contributions | Yes: $8,000 at age 50+, $11,250 at ages 60-63 | Not available |
| Roth option | Yes, standard at most providers | Technically allowed since SECURE 2.0, but rarely offered by brokerages in practice |
| Loans against the balance | Yes, up to the lesser of $50,000 or 50% of the vested balance | Not allowed. IRA funds can't secure a loan |
| Who else you can cover | Only a spouse who earns income from the same business | Every eligible employee, at the same contribution percentage you take |
| Setup deadline | Plan must be established by December 31 of the tax year | Can be opened and funded any time up to your filing deadline, extensions included |
| Annual IRS filing | Form 5500-EZ once plan assets pass $250,000 | None, ever, regardless of balance |
| Contribution timing | Employee deferral can go in throughout the year, before you know full-year profit | Employer contribution is calculated once net earnings are final, usually one lump sum near the filing deadline |
| Investment menu | As wide as your provider allows, including alternative assets at some providers | Standard brokerage menu: funds, stocks, ETFs |
| Required minimum distributions | Start at age 73, moving to age 75 if you were born in 1960 or later | Start at age 73, moving to age 75 if you were born in 1960 or later |
| Early withdrawal penalty | 10% before age 59.5, plus ordinary income tax, unless an exception applies | Same: 10% before age 59.5, plus ordinary income tax |
| Tax treatment if you return to India | Fully taxable as ordinary income on withdrawal. India doesn't recognize either account as tax-advantaged | Same tax treatment as a Solo 401(k) on withdrawal |
| Rolling over if you stop self-employment | Rolls into a traditional IRA or a future employer's 401(k) with no tax hit | Rolls into a traditional IRA or a future 401(k) with no tax hit |
| Cost and complexity to set up | Needs an IRS-approved plan document and a separate trust account | A single-page IRS Form 5305-SEP and a brokerage account, often opened the same day |
Rates, limits, and features are subject to change. Verify current figures with official sources before making decisions.
That $24,500 gap isn't a coincidence.
For a sole proprietor, the employer contribution formula is identical in both plans.
So contributing without an employer match still leaves the employee deferral as the entire reason a Solo 401(k) holds more.
Solo 401(k) vs SEP IRA: which one should you choose?
Both plans are legitimate, and at very high income the totals converge.
The real decision usually comes down to how much you'll actually contribute this year, whether you might hire someone, and how much setup work you want to take on.
What I see in practice
I'd default toward the Solo 401(k) unless your income is too low for the extra paperwork to be worth it, or you're planning to add employees within the next year or two. The loan feature matters more than people expect when you're still building a US credit and asset base.
When to choose a Solo 401(k)
- You haven't hit the $72,000 cap on either plan yet, and want more room than a SEP IRA alone allows
- You want a Roth option your provider actually supports
- You might need to borrow against the balance for a real emergency
- You have no employees and don't plan to hire anyone in this business
- You'd rather set aside part of each payment as it arrives, not wait until year-end
When to choose a SEP IRA
- You want the plan open and funded within a day, with a single IRS form
- Your income swings enough that you don't want ongoing plan maintenance
- You already have, or plan to bring on, a few employees and want the simplest way to cover them too
- You're not going to use the loan feature or a Roth option anyway
- You'd rather avoid Form 5500-EZ filing obligations entirely, even at a large balance
Can you use both?
You can technically sponsor both plans from the same business, but there's little reason to.
Contributions to a Solo 401(k) and a SEP IRA from the same self-employment income share the same overall $72,000 annual limit, so combining them doesn't raise your ceiling.
The one case where holding both makes sense is running two genuinely separate businesses, each with its own net earnings.
If most of your income comes from a single consulting practice, pick one plan for it rather than splitting the paperwork for no extra room.
A cash balance retirement plan becomes worth a look only after you've maxed out a Solo 401(k) or SEP IRA and still want to shelter more.
How InvestMates can help NRIs choose the right self-employed retirement plan
Neither a Solo 401(k) nor a SEP IRA was built with a cross-border NRI in mind.
Both are US domestic retirement vehicles, and the real complexity for you usually starts after the contribution, not before it.
That complexity comes down to three things: what happens to the balance if you move back to India, how withdrawals interact with your visa status, and which contribution formula actually applies once your business structure gets involved.
An InvestMates advisor can walk through your specific setup, sole proprietorship, single-member LLC, or S-corp, and confirm the right formula before you commit to a plan.
If you're weighing a Solo 401(k) or SEP IRA against maxing out a W-2 employer's 401(k) from a day job, deciding which account to prioritize is the natural next step.
For NRIs planning an eventual return to India, an advisor can also map out how these balances get taxed on withdrawal and sequence them alongside your other US accounts.
Book a free consultation with an InvestMates advisor to walk through your self-employment retirement setup before you file.
Solo 401(k) vs SEP IRA: the bottom line
For most self-employed NRIs with steady income and no employees on the horizon, a Solo 401(k) is worth the extra paperwork over a SEP IRA.
That's mainly for the larger contribution room and the loan feature.
If your income is unpredictable, a SEP IRA still gets the job done in a day.
Confirm your exact contribution formula before you fund the plan, since sole proprietors, LLCs, and S-corps calculate it differently.
Frequently asked questions
What is the downside of a Solo 401(k) compared to a SEP IRA?
The main downside is paperwork.
A Solo 401(k) needs an IRS-approved plan document and a separate trust account when you set it up. Once the plan's assets pass $250,000 you also have to file Form 5500-EZ every year.
You'll also need to plan for required minimum distributions once you turn 73, the same as almost any tax-deferred retirement account.
Why might a Solo 401(k) beat a SEP IRA for a self-employed NRI?
A Solo 401(k) usually lets you set aside more money at the same income.
That's because it adds an employee deferral of up to $24,500 in 2026, on top of the same employer contribution a SEP IRA allows.
It also offers a Roth option at most providers and a loan feature the SEP IRA doesn't have.
For a self-employed NRI still building a US credit and asset base, I'd weigh that loan access more heavily than the extra contribution room alone.
Is a self-employed 401(k) the same thing as a Solo 401(k)?
Yes. Self-employed 401(k), one-participant 401(k), individual 401(k), and uni-401(k) are all names for the same plan the IRS calls a one-participant 401(k).
Providers use different marketing names, but the contribution rules, the $72,000 total cap for 2026, and the no-employees-other-than-a-spouse eligibility requirement are identical across all of them.
If I have a W-2 job with a 401(k), does that limit what I can put into a Solo 401(k) or SEP IRA from side self-employment income?
Your employee deferral limit is per person, not per plan, so the $24,500 you can defer in 2026 is shared across your W-2 employer's 401(k) and any Solo 401(k) you open for side self-employment income.
The employer contribution piece is separate for each business, though.
You can still add an employer contribution to your Solo 401(k) or SEP IRA even after maxing out deferrals at your day job.