How MUCH Can My Business Contribute to My Solo 401k?

How MUCH Can My Business Contribute to My Solo 401k?

Watch: My Solo 401k Financial breaks down exactly how much your business can contribute to your Solo 401k for tax year 2026.

One of the most common questions we get every year is: how much can my business contribute to my Solo 401k? The answer depends on your business structure, your earned income, and the annual IRS contribution limits. This post breaks down employer profit-sharing contributions — also known as business or employer contributions — for tax year 2026, including how the calculation changes depending on whether your self-employed business is a sole proprietorship, an S-corporation, a C-corporation, or a partnership.A Solo 401k (also called an individual 401k, single-K, or self-employed 401k) is a 401k plan built for owner-only businesses. One of its biggest advantages is that it allows for multiple contribution types: employee salary deferral contributions, voluntary after-tax contributions, and employer profit-sharing contributions. This article focuses on that last category — how much your business itself can contribute on your behalf.

Important — There’s Still Time for 2025 Employer Contributions: Thanks to SECURE Act 2.0, the deadline to both establish a Solo 401k plan and make employer profit-sharing contributions for the prior tax year was extended to your business tax return due date, plus any timely filed extension. If your self-employed business is an S-corporation and you filed a 2025 tax return extension, you have until September 15, 2026 to open and fund a Solo 401k for 2025. If your business is a sole proprietorship, you have until October 15, 2026.

2026 Solo 401k Contribution Limits

For tax year 2026, the overall contribution limit to a Solo 401k plan is $72,000. This overall limit applies to the combined total of employee contributions, employer contributions, and voluntary after-tax contributions (catch-up contributions are separate and are never considered employer contributions).

Contribution Type 2026 Limit
Employee salary deferral $24,500
Catch-up contribution (age 50+) $8,000
Super catch-up contribution (ages 60–63) $11,250 (instead of the standard catch-up, not both)
Overall Solo 401k limit (employee + employer + voluntary after-tax) $72,000

How Employer Profit-Sharing Contributions Are Calculated

The IRS allows one-participant 401k plans (Solo 401k plans) to accept employer profit-sharing contributions of up to 25% of compensation, though the actual formula used to get there depends entirely on how your business is taxed. Special calculations apply for self-employed individuals. Here’s how the calculation breaks down by entity type:

Business Structure Employer Contribution Formula
Sole proprietorship / single-member LLC taxed as a sole proprietorship 20% of adjusted net self-employment income (Schedule C, Line 31, minus one-half of self-employment tax)
S-corporation or C-corporation (or LLC taxed as either) 25% of gross W-2 wages (Box 1)
Partnership / LLC taxed as a partnership 20% of adjusted self-employment earnings (Schedule K-1, Line 14, Code A, minus one-half of self-employment tax)
Example — S-Corporation: If you report $100,000 of W-2 wages (Box 1) from your self-employed S-corporation, your maximum employer profit-sharing contribution is $100,000 × 25% = $25,000. You cannot contribute more than 25% of your W-2 wages as an employer contribution, whether made pre-tax or as a Roth Solo 401k employer contribution.
Example — Sole Proprietorship / Partnership: Take your Schedule C, Line 31 income (or Schedule K-1, Line 14, Code A for a partnership), subtract one-half of self-employment tax, then multiply the result by 20%. My Solo 401k Financial’s online Solo 401k contribution calculator performs this calculation for you automatically.

You Need W-2 Wages to Support an S-Corp Contribution

Warning: Even though an employer profit-sharing contribution is deductible on your business tax return, you must have the W-2 wages to support it. If your S-corporation only reports $10,000 of W-2 wages, your maximum employer profit-sharing contribution is $10,000 × 25% = $2,500 — not $25,000. Solo 401k contributions for an S-corp are driven entirely by Box 1 gross wages, so make sure your payroll supports the contribution you’re planning to make.

Can Employer Contributions Be Made as Roth?

Yes — and you have SECURE Act 2.0 to thank for that. Traditionally, employer profit-sharing contributions are made pre-tax so the business receives a tax deduction. Under SECURE Act 2.0, Solo 401k plans offered by providers like My Solo 401k Financial can also accept employer Roth Solo 401k contributions.

Info Highlight: An employer Roth Solo 401k contribution is deductible on the business tax return, but it’s treated as a taxable in-plan conversion on your personal return. Because of this, most clients skip employer Roth contributions and instead use the Mega Backdoor Roth strategy: making voluntary after-tax Solo 401k contributions and immediately converting them to a Roth Solo 401k or Roth IRA. Voluntary after-tax contributions are calculated dollar-for-dollar rather than as a percentage of compensation, which typically allows for a much larger Roth conversion opportunity than an employer Roth contribution would.

Spousal Contributions Can Double Your Household Savings

If your spouse works in your business and earns compensation from it, he or she doesn’t need to be an owner to participate. Your spouse can join the same Solo 401k plan — it remains one plan sponsored by the business, not a second plan — and can make his or her own employee, employer, and voluntary after-tax contributions, each subject to the same 2026 limits.

In a two-participant plan (both spouses), each spouse typically has three separate holding accounts (pre-tax, Roth, and voluntary after-tax), for a total of six accounts. My Solo 401k Financial can help set these up at Fidelity, Schwab, or another brokerage or bank of your choosing.

Contributing to Your Solo 401k While Also Having a Day-Job 401k

Many self-employed individuals also work a W-2 day job with its own 401k. Here’s how the rules interact:

Contribution Type Aggregated Across Both Plans?
Employee salary deferral ($24,500 for 2026) Yes — shared across all 401k plans you contribute to
Employer profit-sharing contribution No — calculated separately for your Solo 401k
Voluntary after-tax contribution No — calculated separately for your Solo 401k

In other words, even if you’ve maxed out your day-job 401k, you can still make full employer profit-sharing and voluntary after-tax contributions to your Solo 401k, up to the overall $72,000 limit for 2026.

Eligibility: Who Can Have a Solo 401k?

A Solo 401k is for owner-only businesses, meaning you generally cannot have any non-owner, full-time common-law employees who work 1,000+ hours per year. There are a few exceptions: a working spouse (does not need to be an owner), independent contractors, and any employee under age 21, regardless of hours worked.

Important — Ongoing Eligibility Rules: Under SECURE Act 2.0’s long-term part-time employee rule, if you hire a non-owner, non-spouse W-2 employee who works between 500 and 999 hours for two consecutive years, you’ll need to close the Solo 401k, transfer it to an IRA, or convert it to a full employer 401k plan after that two-year period. The same applies if a W-2 employee works 1,000+ hours in any 12-month period.

EIN Reporting: Solo 401k vs. Business EIN

Info Highlight: A Solo 401k is a separate legal trust with its own EIN — you do not use your business EIN to open the holding accounts. That Solo 401k EIN is used for Form 1099-R reporting (for example, when processing a Mega Backdoor Roth conversion). However, once your Solo 401k’s market value exceeds $250,000, you’ll file an informational Form 5500-EZ using your business EIN, not the Solo 401k’s EIN.

New for 2026: Mandatory Roth Catch-Up Contributions

Important — Effective January 1, 2026: Under new SECURE Act 2.0 regulations, if your self-employed business is taxed as an S-corporation or C-corporation and your 2025 Form W-2, Box 3 (Social Security wages) was $150,000 or more, your catch-up and super catch-up contributions must be made as Roth Solo 401k contributions — they can no longer be made pre-tax. This rule does not apply to sole proprietorships or partnerships, and it does not apply in the first year a new S-corp or C-corp is established, since there’s no prior-year W-2 to reference.

Key Takeaways

Topic 2026 Takeaway
Overall Solo 401k limit $72,000 (not counting catch-up contributions)
Sole prop / partnership employer contribution 20% of adjusted net self-employment income
S-corp / C-corp employer contribution 25% of W-2 wages (Box 1)
Earned income requirement No W-2 wages or self-employment income means no contributions of any kind

The bottom line: how much your business can contribute to your Solo 401k depends on your business structure and your earned income. Understanding the right formula for your entity type — and keeping your W-2 wages or self-employment income properly documented — is essential to maximizing your employer profit-sharing contribution each year.

About the $1,500 Auto-Contribution Tax Credit

My Solo 401k Financial was the first provider in the industry to offer the auto-contribution feature, which qualifies eligible plans for a tax credit under the SECURE Act. The credit is claimed as $500 per year for three consecutive years (a total of $1,500), filed using Form 8881, and can help offset the cost of maintaining a Solo 401k.

Ready to Maximize Your Solo 401k Contributions?Whether you’re a sole proprietor, an S-corp, a C-corp, or a partnership, My Solo 401k Financial can help you calculate your maximum employer profit-sharing contribution and set up the right Solo 401k structure — including Mega Backdoor Roth and spousal participant accounts.

Next Steps:

Get Started Today, watch more of our videos, or read more articles on our blog!

Remember: This information is provided for educational purposes only. Always consult with qualified tax, legal, and investment professionals before making investment decisions with your retirement funds.

BREAKING: Edward Jones Exits Solo 401k Plans — What Owner K Clients Must Do Before IRS Deadline

BREAKING: Edward Jones Exits Solo 401k Plans — What Owner K Clients Must Do Before IRS Deadline

Watch: Full breakdown of the Edward Jones Owner K exit letter, key deadlines, your options, and cost & feature comparison

In an official client notification letter dated June 29, 2026, Edward Jones announced it is exiting the Solo 401k plan document business. Effective December 31, 2026, Edward Jones will discontinue providing the plan document — and all document maintenance services — for its Owner K (Solo 401k) plans. If you are self-employed and sponsor an Owner K plan, or you are an Edward Jones financial advisor with clients who do, this announcement affects you directly — and the clock is already ticking on multiple deadlines.

Critical Clarification: Per the official Edward Jones notice, this change has NO impact on your investment advisory or custodial services at Edward Jones — those continue completely uninterrupted. Only the underlying plan document is affected. Your investment accounts stay right where they are, regardless of which plan document provider you choose. This is a paperwork decision, not an investment decision.

Why Is Edward Jones Discontinuing Owner K Plan Documents?

According to the letter, the regulatory changes in the SECURE 2.0 Act expanded plan design options beyond what the Edward Jones Owner K prototype document permits. Rather than update its document, Edward Jones is exiting the plan document business and directing clients to a third-party provider. The IRS requires that all Solo 401k plans be amended for the SECURE 2.0 Act by December 31, 2026, and the Edward Jones service end date aligns with that deadline.

Critical Deadlines Every Owner K Client Must Know

Date What Happens
August 14, 2026 Deadline to notify your Edward Jones advisor if you do NOT want your plan data (EIN, address, email, plan elections) automatically shared with FuturePlan
Mid-August 2026 Plan data transfers to FuturePlan by default for clients who do not opt out
Early Fall 2026 FuturePlan begins distributing pre-selected plan documents for signature
December 31, 2026 Edward Jones document support ends; IRS SECURE 2.0 restatement deadline; plan otherwise converts to an “individually designed plan” with no document sponsor
End of 2027 Outside window to retroactively adopt a new pre-approved plan document
Important — The Risks of Doing Nothing: If you fail to adopt a SECURE 2.0-compliant plan document by 12/31/2026, your plan ceases to be a pre-approved plan and risks tax penalties, up to and including plan disqualification and loss of tax-favored status. Separately, if you do not opt out by August 14, 2026, Edward Jones will automatically transmit your plan’s data to FuturePlan — you forfeit your decision-making window and are defaulted to a pre-selected provider.

Your Three Options as an Edward Jones Owner K Client

Option 1: Default to FuturePlan

Do nothing and your plan transitions to FuturePlan, the document provider Edward Jones has arranged. You will pay a $150 one-time SECURE 2.0 amendment fee in 2026 plus a $150 annual document maintenance fee starting in 2027 — and the restrictive brokerage prototype plan design is expected to remain fully in place.

Option 2: Upgrade to a Specialized Solo 401k Provider

Restate your plan onto a flexible plan document with My Solo 401k Financial — keeping your existing Edward Jones investment accounts in place while unlocking premium plan features like the Mega Backdoor Roth, participant loans, tax credits, and alternative investments.

Option 3: Terminate the Plan

You may terminate your Owner K plan — but note that IRS rules still require your plan document to be updated in connection with a termination, so a compliant restated document is needed either way.

Cost Comparison: FuturePlan vs. My Solo 401k Financial

Fee / Service Element FuturePlan (Default) My Solo 401k Financial
One-Time Amendment Fee $150 (due in 2026) Included in flat initial fee
Annual Document Maintenance $150/year (first due 2027) Included in flat ongoing fee
IRS Form 5500-EZ Compliance Not provided (extra service) Included at no additional cost (simply timely request)
IRS Form 1099-R Preparation Not provided (extra service) Included at no additional cost (simply timely request)
Third-Party Administrator (TPA) Fees “Strongly recommended” by Edward Jones at extra cost No TPA or separate fees required

Features, Not Just Fees: What the Default Plan Still Won’t Allow

The bigger issue is plan design. FuturePlan is expected to simply restate the existing restrictive Edward Jones brokerage prototype — meaning the same limitations remain in place. Compare the plan features side by side:

Plan Feature FuturePlan My Solo 401k Financial
Mega Backdoor Roth Contributions ❌ ✅
$1,500 SECURE Act Tax Credits ❌ ✅
Participant Loans (borrow up to $50,000) ❌ ✅
Alternative Investments (real estate, notes, crypto, metals) ❌ ✅
Open Architecture Custody Model ❌ ✅
Keep Your Edward Jones Accounts: Our open custody model means restating to a Solo 401k plan with My Solo 401k Financial does not require moving your existing Edward Jones brokerage accounts. You keep your advisor relationship and investments in place — while gaining the plan features above.

Deep Dive: The Mega Backdoor Roth Opportunity

The Mega Backdoor Roth strategy allows you to make voluntary after-tax contributions up to the overall annual IRS Section 415(c) limit (e.g., $72,000 for 2026) and then convert those funds to a Roth Solo 401k or Roth IRA — building tax-free retirement wealth far beyond standard contribution limits.

The Hurdle: Standard brokerage prototype documents — including the Edward Jones Owner K document and the expected FuturePlan restatement — specifically block voluntary after-tax contributions, making the Mega Backdoor Roth impossible. A specialized plan document that supports after-tax contributions is required to use this strategy.

Deep Dive: Claim $1,500 in Tax Credits

Under the SECURE Act, solopreneurs can claim a federal tax credit of $500 per year for 3 consecutive years — $1,500 total — simply for adding automatic enrollment to their Solo 401k plan. The catch: your plan document must natively support an Eligible Automatic Contribution Arrangement (EACA) provision. Basic institutional prototypes like the Edward Jones and FuturePlan documents do not support EACA — while My Solo 401k Financial plan documents fully include it, making you eligible to claim these credits.

The Restatement Process: 5 Simple Steps

Step 1: Apply Online

Submit your current plan details and payment in minutes – click HERE to get started.

Step 2: Document Preparation

Our team drafts your custom SECURE 2.0-compliant restated plan documents within the same business day.

Step 3: Sign

Sign and finalize your newly restated plan adoption agreement.

Step 4: No Asset Transfers Required

Your Edward Jones investment accounts stay exactly where they are — consistent with the Edward Jones notice confirming advisory and custodial services continue uninterrupted.

Step 5: Ongoing Support

We handle ongoing tax reporting support (Form 5500-EZ and Form 1099-R — simply timely request) plus all future IRS-required amendments and restatements.

Pro Tip: If you plan to choose your own document provider, remember to opt out of default data sharing with FuturePlan by notifying your Edward Jones advisor before August 14, 2026.

A Note for Edward Jones Financial Advisors

If your clients received this letter, the most important reassurance you can offer is this: transitioning the plan document does not require moving assets away from your firm. Advisory continuity is guaranteed by the original exit notice itself. Partnering with a specialized document provider allows you to protect the client relationship while delivering highly desired features — Mega Backdoor Roth, participant loans, and SECURE Act tax credits — that standard institutional prototypes cannot offer.

Received the Edward Jones Owner K Letter? Turn Forced Change Into an Upgrade.

Restate your Solo 401k to a plan that unlocks the Mega Backdoor Roth, $1,500 in tax credits, participant loans, and alternative investments — while keeping your Edward Jones accounts exactly where they are.

Next Steps:
Get Started Today!

Remember: This information is provided for educational purposes only. Always consult with qualified tax, legal, and investment professionals before making investment decisions with your retirement funds.

Every Way to Fund a Roth Solo 401k in 2026 (And the One Way You Can’t)

Every Way to Fund a Roth Solo 401k in 2026 (And the One Way You Can’t)

The Roth Solo 401k is consistently one of the most requested topics among new Solo 401k account holders. A plan gets established — often with accounts at Schwab or Fidelity — and immediately the principal question emerges: How do I actually get funds into the designated Roth account?

In this guide, we take an in-depth look at every path into the designated Roth account of a Solo 401k in 2026, the hidden strategy rules that determine which path works best, and the single transaction type prohibited by the IRS.

Watch: Every way to fund a Roth Solo 401k in 2026 — and the one way you can’t

First, Understand the Solo 401k Account Structure

Before walking through each funding “door,” it helps to understand how a Solo 401k holds different money types. A Solo 401k is a retirement trust, and the self-employed business owner serves as trustee. With a plan from My Solo 401k Financial, each contribution type is tracked in its own sub-account — for example, a pre-tax account, a voluntary after-tax account, and a designated Roth account.

Unlike a brokerage prototype plan, we are not the custodian and do not have access to your funds. Instead, we help customers open accounts at the bank or brokerage of their choice — whether that’s Fidelity, Schwab, or elsewhere. If two participants (say, a husband and wife working in the same business) each want pre-tax and Mega Backdoor Roth capability, that one plan would have six separate accounts for the one solo 401k plan (Pre-tax, Roth and Voluntary After-tax for each spouse).

Info: When opening the bank account, use language the bank understands: you are the trustee of a retirement trust, with an EIN for the trust and a certificate of trust. Approaching the bank this way avoids being incorrectly steered toward opening an IRA.

Door #1: Direct Roth Contributions

Roth Employee Contributions

The most familiar path is the Roth employee contribution, made from your earned self-employment compensation directly into the designated Roth account. The limit is 100% of your self-employment compensation, dollar for dollar, up to $24,500 for 2026 — or more if you’re age 50 or older.

Age (as of end of 2026) Catch-Up Amount Total Employee Contribution
Under 50 N/A $24,500
50–59 or 64+ $8,000 $32,500
60–63 (super catch-up under SECURE Act 2.0) $11,250 $35,250

These limits assume you didn’t make employee contributions to another plan, such as a day-job 401k. Reporting depends on how your business is taxed: if your business is taxed as an S-corporation or C-corporation, the Roth employee contribution is reported on your W-2. If your business is taxed as a sole proprietorship (including a single-member LLC taxed as a sole proprietorship) or a partnership, Roth employee contributions are not reported on your personal or business tax return — and no Form 1099-R is required.

Important — 2026 Mandatory Roth Catch-Up: Thanks to SECURE Act 2.0, beginning in 2026, if your prior-year FICA wages (W-2 Box 3) from your self-employed business exceeded $150,000, all catch-up contributions must be made on a Roth basis. If your self-employed business doesn’t pay you a W-2 (e.g., you’re a sole proprietor), this mandatory Roth catch-up rule does not apply — though you always retain the option to make catch-up contributions as Roth.

Roth Employer Contributions

Historically, employer contributions were always pre-tax, but SECURE Act 2.0 now allows employer contributions to be designated as Roth contributions. In our experience, however, this option is virtually never used by our clients — because they already have the ability to make Mega Backdoor Roth contributions, which win on two fronts:

1. Lower income requirement. The employer contribution limit is a percentage of compensation — 20% of self-employment compensation for a sole proprietorship or partnership, or 25% of W-2 wages for an S-corp or C-corp. That means you need a multiple of your desired contribution in compensation to justify it. By contrast, voluntary after-tax contributions can be 100% of self-employment compensation, dollar for dollar, up to the overall limit — so you hit the ceiling with far less income.

2. Simpler tax reporting. A Roth employer contribution is tax-deductible on the employer’s return for the year the contribution is made but taxable to the employee for the year it’s deposited. The Mega Backdoor Roth is more streamlined: the after-tax contribution itself isn’t reportable on your personal or business return, and only the after-tax-to-Roth transfer is reported (via Form 1099-R — which we prepare for no additional charge for those who submit the required info in a timely fashion).

Door #2: In-Plan Conversions (Including the Mega Backdoor Roth)

The Mega Backdoor Roth Solo 401k

The Mega Backdoor Roth is one of the top use cases among our customers, and it’s the fastest way to reach the 2026 overall ceiling of $72,000. It’s a two-step process:

Step 1: Make voluntary after-tax contributions to a separate after-tax sub-account — up to 100% of your self-employment compensation, dollar for dollar, up to the overall limit.
Step 2: Convert those after-tax dollars to a Roth account, where they can be invested with tax-free growth potential.

Example: As long as you have at least $72,000 of self-employment compensation in 2026, you could contribute 100% of it as a voluntary after-tax contribution to the Solo 401k and then transfer those dollars to your Roth account. At the end of the day, you’ve got $72,000 in a Roth account for 2026 — assuming you made no other Solo 401k contributions, and no contributions were made to a 403b by you or on your behalf (403b contributions aggregate with Solo 401k contributions toward the overall limit).

With our plan, you have two destination options for converted after-tax funds:

Destination Why Choose It
Roth Solo 401k (stay in the plan) Preserves the ability to take a Solo 401k participant loan (you cannot take a loan from a Roth IRA) and to easily invest in alternative investments within the plan.
Roth IRA (transfer out of the plan) Best for those satisfied with an existing Roth IRA’s performance who want to accumulate dollars there. To invest Roth IRA dollars in alternative investments, you’d need a specialty self-directed Roth IRA provider.
Warning: The choice to transfer voluntary after-tax funds out of the plan to a Roth IRA is a one-way street. Once dollars land in a Roth IRA, they can never be rolled back into any type of 401k — including a Solo 401k. Choose your destination carefully.

Pre-Tax to Roth In-Plan Conversions

The other conversion strategy is to take pre-tax dollars already inside your Solo 401k — for example, funds previously rolled in from a former employer plan or a pre-tax IRA — and convert all or some of them to the Roth Solo 401k. Key features:

  • No dollar limit on how much you can convert.
  • No triggering event required.
  • Taxable and reportable for the year of conversion, since funds move from pre-tax to Roth status.
  • In-kind conversions allowed: if you’ve made a specific investment in the pre-tax account, you don’t have to liquidate to cash — the position can be transferred in kind to the Roth account.
Info: We handle the required Form 1099-R reporting for both Mega Backdoor Roth transfers and pre-tax Roth conversions for no additional charge. Customers or their advisors simply submit the reporting form on our website — accessible 24/7 — in a timely fashion.

Door #3: Rollovers Into the Solo 401k

The third door is transferring money from another retirement account into your Solo 401k. Under the rules, you can roll in funds from:

  • A pre-tax IRA (and then you can process an in-plan taxable Pre-tax Solo 401k to Roth Solo 401k conversion)
  • A pre-tax former employer plan (e.g., a 401k, 403b, or similar) (and then you can process an in-plan taxable Pre-tax Solo 401k to Roth Solo 401k conversion)
  • Roth dollars in a former employer plan — for example, a Roth 401k at a previous job can roll directly into your Roth Solo 401k

The One Way You Can’t: Roth IRA to Solo 401k

Prohibited by the IRS: You cannot roll over a Roth IRA to any type of 401k — including a Solo 401k. This is a strict one-way street. You can transfer voluntary after-tax Solo 401k funds out of the plan to a Roth IRA, but you can never bring them back, because the Roth IRA rules simply don’t allow Roth IRA dollars to move into any 401k.

Quick Reference: Every Path Into the Roth Solo 401k for 2026

Funding Method 2026 Limit Allowed?
Roth employee contribution $24,500 (+ $8,000 or $11,250 catch-up) ✅ Yes
Roth employer contribution (SECURE Act 2.0) 20%/25% of compensation ✅ Yes (rarely used)
Mega Backdoor Roth (after-tax → Roth) Up to $72,000 overall limit ✅ Yes
Pre-tax to Roth in-plan conversion No limit ✅ Yes (taxable)
Rollover of Roth 401k from former employer No limit ✅ Yes
Rollover from a Roth IRA — ❌ Prohibited

Ready to Start Building Tax-Free Wealth in a Roth Solo 401k?

Whether you plan to make Roth employee contributions, run the Mega Backdoor Roth strategy, or convert pre-tax dollars, My Solo 401k Financial can help you set up the right Solo 401k structure — with plan documents prepared the same business day and Form 1099-R reporting handled at no additional charge.

Next Steps:
Get Started Today!

Remember: This information is provided for educational purposes only and should not be construed as tax, legal, or investment advice. Always consult with qualified tax, legal, and investment professionals before making investment decisions with your retirement funds.

Married Solopreneurs: How to Save $144K into Mega Backdoor Roth for 2026

Married Solopreneurs: How to Save $144K into Mega Backdoor Roth for 2026



Watch: How a married couple can save $144,000 into a Mega Backdoor Roth for 2026 using a Solo 401k



If both spouses work in the same owner-only business, 2026 opens the door to one of the most powerful Roth savings strategies available to the self-employed. Using the Mega Backdoor Roth feature of a Solo 401k, each spouse can move up to $72,000 into Roth dollars — for a combined $144,000 of tax-advantaged retirement savings in a single year. This is roughly ten times what a person could contribute to a Roth IRA directly, and those dollars carry the same tax-free growth potential as any other Roth funds.

Below, we break down exactly how the $144,000 figure works, who qualifies, the two-step process behind each $72,000 contribution, and the deadlines you need to know.



How the $144,000 Adds Up

The $144,000 figure comes from two separate $72,000 contributions — one for each spouse. When a married couple both work in the same self-employed business, both participate in the same Solo 401k plan, and each has enough earned income to justify it, each spouse can independently make a $72,000 Mega Backdoor Roth contribution.

Participant Maximum Mega Backdoor Roth Contribution (2026)
Spouse 1 $72,000
Spouse 2 $72,000
Combined Household Total $144,000
Info Highlight: Two core principles govern these contributions — (1) you can’t save more than you earn, and (2) a Solo 401k is designed for self-employed individuals to save their earned self-employment compensation. Each spouse’s $72,000 must be supported by their own self-employment income.



Who Qualifies: The Owner-Only Rule

The Solo 401k is reserved for owner-only businesses. Both spouses can work in and contribute to the plan, but neither spouse’s business can have any non-owner, non-spouse, full-time W-2 employees.

What Counts as a Full-Time W-2 Employee?

A full-time W-2 employee — the kind that would disqualify you — is someone who is:

Factor Threshold
Age 21 years or older
Hours (standard) 1,000 hours per year with a year of service
Hours (long-term part-time) 500 hours per year for two consecutive years
Example: A married couple runs an online consulting business with no other employees. Both spouses actively work in the business and each reports earned self-employment income. Because no one falls into the full-time W-2 employee category and both spouses have earned income, both spouses can participate in the Solo 401k and pursue the Mega Backdoor Roth.



Anatomy of the $72,000 Contribution

The Mega Backdoor Roth is a two-step process:

Step 1 — Make the Voluntary After-Tax Contribution

You first make a voluntary after-tax contribution to your Solo 401k. The voluntary after-tax limit is 100% of your self-employment compensation, dollar for dollar, up to the overall limit of $72,000 — assuming you make no other contributions to the Solo 401k (you skip the employee and employer contribution types and make a pure voluntary after-tax contribution).

Step 2 — Convert to Roth

You then transfer (convert) those voluntary after-tax dollars to a Roth Solo 401k or a Roth IRA. The funds can move into a separate Roth account opened under the name and EIN of the Solo 401k, or be transferred out of the plan to a Roth IRA. Either way, they then enjoy tax-free growth potential.

Important — The 403(b) Exception: The $72,000 voluntary after-tax limit assumes no contributions are being made to a 403(b) plan. Normally, contributions to another plan (such as a day-job 401k) don’t reduce your ability to make voluntary after-tax Solo 401k contributions. The exception is a 403(b): any contributions to a 403(b) — whether employee or employer — combined with what you want to contribute to your Solo 401k cannot exceed the overall limit.



What Counts as Self-Employment Compensation?

Because the voluntary after-tax limit is 100% of self-employment compensation up to $72,000, the next question is: what exactly is self-employment compensation? It depends on how your business is taxed.

Business Tax Treatment How Self-Employment Compensation Is Determined
Sole Proprietor
(incl. single-member LLC taxed as sole prop)
Line 31 of Schedule C (net income after business expenses), less one-half of the self-employment tax
S-Corporation or C-Corporation The W-2 wages you receive from your self-employed business
Partnership Net income reported on Line 14 of the K-1 you receive, less one-half of the self-employment tax

As long as that calculated amount is at least $72,000 for each spouse, the full Mega Backdoor Roth contribution is available to that spouse.



The Step-by-Step Procedure

1. Confirm Eligibility

Verify that you have an owner-only business and that both spouses report earned self-employment income.

2. Adopt a Solo 401k That Allows the Mega Backdoor Roth

Your plan documents must allow both steps — the voluntary after-tax contribution and the subsequent transfer to a Roth Solo 401k or Roth IRA. My Solo 401k Financial was the first Solo 401k provider to offer a plan supporting the Mega Backdoor Roth, and our documents allow it.

3. Open the Accounts

We are completely neutral on where accounts are opened — we don’t hold customer funds and don’t have access to the accounts — but we are hands-on in helping you open accounts at the bank or brokerage of your choice. Popular brokerage options include Fidelity and Schwab, and we’ve helped customers open accounts at hundreds of banks and credit unions nationwide.

4. Use Separate Accounts for Each Spouse

When both spouses participate, separate accounts are required for each. Each spouse needs their own voluntary after-tax account opened under the name and EIN of the Solo 401k for the benefit of that spouse.

5. Contribute, Then Convert

Each spouse contributes up to $72,000 to their voluntary after-tax account, then converts those dollars to a Roth Solo 401k or Roth IRA.



Is the Conversion Taxable?

There is no tax on the conversion of the after-tax principal. If no gains have accrued in the voluntary after-tax account at the time of conversion, the entire conversion is tax-free. If some gains have accrued before the funds are moved to the Roth account, only that small gains portion is taxable in the year of conversion.

Example: Assume a couple’s business is taxed as an S-corporation and each spouse receives $72,000 in W-2 wages. Each spouse contributes $72,000 as a voluntary after-tax contribution, then promptly converts $72,000 to their respective Roth Solo 401k or Roth IRA — $144,000 combined — with tax-free growth potential going forward. Because they convert quickly before gains accrued in the voluntary after-tax solo 401k account, there are no gains to be taxed at conversion.



Deadlines to Know

Action Deadline
Make the voluntary after-tax contribution (for 2026) Business tax return deadline, including any timely filed extension (in 2027 for the 2026 contribution)
Convert to Roth No deadline — though most convert shortly after contributing
Important: While there’s no deadline to convert, most people convert soon after making the contribution — both to start investing for tax-free growth sooner and to minimize any gains in the voluntary after-tax account that would be taxable at conversion.



Beyond the Mega Backdoor Roth: More Reasons to Set Up a Solo 401k

The Mega Backdoor Roth is a leading reason solopreneurs open a Solo 401k with My Solo 401k Financial, but it’s far from the only one:

Additional Roth Options

Beyond the Mega Backdoor Roth, you can make other types of Roth contributions and perform Roth conversions — converting existing pre-tax Solo 401k dollars to Roth status.

Tax Credits

Our plan was the first offered by a Solo 401k provider to support the ability to claim tax credits under the SECURE Act — up to $1,500 total ($500 per year for three consecutive years). These credits are available not only to new plans but also to existing plans (for example, a basic plan at Fidelity or Schwab) that are upgraded to our plan to enable Mega Backdoor Roth and other features.

Alternative Investments

Our plan allows brokerage-type investments (stocks, bonds, mutual funds) plus true diversification into alternatives such as real estate, private placements, private stock, precious metals, and crypto.

Participant Loans

You can take a Solo 401k participant loan for any purpose — personal or business — without taxes or penalties, provided you stay within the loan terms: borrow up to 50% of the balance, not to exceed $50,000, properly documented. Interest is prime plus 1% (or a CD rate plus 2%), repaid in equal monthly or quarterly payments of principal and interest over a five-year term (longer if used to buy a primary residence). We prepare the required loan documents at no additional charge.

Compliance Support

We handle the Form 5500-EZ and 1099-R when needed, as long as we’re notified in a timely fashion. Note that a Form 5500-EZ isn’t required until the value of your Solo 401k (including any defined benefit plan) exceeds $250,000.



Ready to Save $144,000 into a Mega Backdoor Roth for 2026?

If you and your spouse run an owner-only business, we can help you set up the right Solo 401k structure to make the most of the Mega Backdoor Roth — including separate accounts for each spouse, the right conversion path to a Roth Solo 401k or Roth IRA, and ongoing compliance support.

Next Steps:
Get Started Today

Remember: This information is provided for educational purposes only and should not be construed as tax, legal, or investment advice. Always consult with qualified tax, legal, and investment professionals before making decisions with your retirement funds.

How are Solo 401k Contributions REPORTED to IRS?

How are Solo 401k Contributions REPORTED to IRS?

This is one of the most common questions My Solo 401k Financial receives from owner-only businesses: how do I report the contributions I make to my Solo 401k to the IRS? The honest answer is — it depends. It depends on the type of contribution you’re making (employee pre-tax, employee Roth, employer pre-tax, employer Roth, or voluntary after-tax) and on how your self-employed business is taxed (sole proprietorship, S-corporation, C-corporation, or partnership). In this guide, we walks through exactly where each contribution type gets reported, no matter your business structure.

Watch: My Solo 401k Financial explains exactly how Solo 401k contributions get reported to the IRS

2025 and 2026 Solo 401k Contribution Limits

Before diving into reporting, it helps to know the overall contribution ceiling. A Solo 401k offered by My Solo 401k Financial allows for employee contributions, employer contributions, and voluntary after-tax Solo 401k contributions — the building block of the Mega Backdoor Roth Solo 401k strategy.

Contribution Type Tax Year 2025 Tax Year 2026
Overall contribution limit $70,000 $72,000
Super catch-up (ages 60–63) $11,250 $11,250

ℹ️ Super Catch-Up vs. Normal Catch-Up

The $11,250 super catch-up contribution first became effective in 2025 and remains the same for tax year 2026. It’s only available to those who are age 60, 61, 62, or 63. You cannot make both a normal catch-up contribution and a super catch-up contribution in the same year if you fall within that age range — you have to choose one or the other.

Reporting for Sole Proprietorships (Schedule C)

If your self-employed business is a sole proprietorship — or an LLC taxed as a sole proprietorship, or you’re a 1099 contractor filing a Schedule C — the process starts with identifying Line 31 of Schedule C, the net profit line from self-employment activity. That’s your starting figure for calculating any Solo 401k contribution, whether employee, employer, or voluntary after-tax.

💡 How to Calculate Your Contribution

Start with Schedule C, Line 31 (net profit). Subtract one-half of self-employment income tax from that figure. Then plug the resulting net number into the Solo 401k contribution calculator found on the My Solo 401k Financial website — the calculator will perform the rest of the calculation for you automatically.

Where Sole Proprietorship Contributions Get Reported

Contribution Type Where It’s Reported
Employee pre-tax contribution Schedule 1, Line 16 (attached to Form 1040)
Employer pre-tax profit-sharing contribution Schedule 1, Line 16 (attached to Form 1040)
Employee Roth contribution Not reported anywhere on your tax return
Employer Roth contribution Schedule 1, Line 16 — but also triggers a taxable in-plan conversion (see warning below)
Voluntary after-tax contribution Not reported on your tax return — instead reported on Form 1099-R, Box 5, when converted (see Mega Backdoor Roth section below)

⚠️ Employer Roth Contributions Have a Hidden Tax Catch

Employer Roth Solo 401k contributions are allowed — but don’t get too excited. When you make an employer Roth Solo 401k contribution, you have to treat it as a taxable in-plan conversion. If you’re trying to maximize your Roth Solo 401k contributions, you should not do it through the employer Roth contribution. Instead, use the voluntary after-tax Solo 401k contribution, which can then be converted to the Roth Solo 401k. It’s more advantageous because it’s calculated dollar-for-dollar, whereas employer Roth contributions are calculated as a percentage — effectively 20% of Schedule C Line 31 income after subtracting one-half of self-employment income tax.

How the Mega Backdoor Roth Solo 401k Gets Reported

Voluntary after-tax Solo 401k contributions are not reported on your personal or business tax return for a sole proprietorship. Instead — and this is the part that catches people off guard — they get reported on Form 1099-R, Line 5a (Box 5).

ℹ️ Why a 1099-R Gets Issued

The Form 1099-R gets issued when you perform the Mega Backdoor Roth Solo 401k conversion — meaning you make the voluntary after-tax Solo 401k contribution into that specific holding account, and then immediately convert those funds to the Roth Solo 401k or Roth IRA. The 1099-R reports that conversion, not the contribution itself.

My Solo 401k Financial will automatically report that 1099-R for you for the Mega Backdoor Roth conversion — as long as you complete their online conversion form, found in the Forms section of their website. My Solo 401k Financial does not have access to client funds, so timely completion of that form is essential; as long as it’s submitted on time, they will issue the form with a copy sent to you and an electronic copy filed with the IRS, at no extra charge.

💡 My Solo 401k Financial Pioneered This Strategy

My Solo 401k Financial was the first in the industry to offer the Mega Backdoor Roth Solo 401k and has processed thousands of these conversions for clients over the years.

Reporting for S-Corporations and C-Corporations

If your self-employed business is an S-corporation, an LLC taxed as an S-corporation, or a C-corporation, the starting figure is different. You’ll first need to determine your W-2 wages from the business — based on Box 1 of your W-2 (gross wages). You may need to add the amount listed in Box 12 to that figure to arrive at your gross W-2 wages, which is what you’ll use to calculate all your Solo 401k contributions.

Where S-Corp and C-Corp Contributions Get Reported

Contribution Type S-Corporation C-Corporation
Employee pre-tax contribution Schedule 1, Line 16 (personal Form 1040) Schedule 1, Line 16 (personal Form 1040)
Employee Roth contribution Box 12, Code AA on Form W-2 (check Box 13, Retirement Plan); not deductible Box 12, Code AA on Form W-2; not deductible
Employer pre-tax profit-sharing contribution Form 1120-S, Line 17 Form 1120, Line 33
Employer Roth contribution Form 1120-S, Line 17 (deductible) — but taxable in-plan conversion reported on Form 1099-R, Lines 5a/5b Form 1120, Line 23 (deductible) — but taxable in-plan conversion reported on Form 1099-R, Lines 5a/5b

💡 Example: $25,000 Employer Roth Contribution for an S-Corp

Suppose your self-employed business is taxed as an S-corporation, and you make a $25,000 employer Roth Solo 401k contribution. You would report that $25,000 on Form 1120-S, Line 17 as a deduction on the business return. But because it must be treated as a taxable in-plan conversion, a Form 1099-R would also be issued — listing $25,000 on Line 5a (amount converted) and $25,000 again on Line 5b (taxable amount). That $25,000 taxable amount then flows through to Lines 5a and 5b of your Form 1040, under the “Pensions and Annuities” section.

⚠️ Employee Roth Solo 401k Contributions Use a Different Reporting Method for S-Corps/C-Corps

Unlike a sole proprietorship (where employee Roth contributions simply aren’t reported anywhere), an S-Corp or C-Corp employee Roth Solo 401k contribution gets listed in Box 12, Code AA of the Form W-2, and Box 13 (“Retirement Plan”) should be checked. It’s still not deductible, since employee Roth Solo 401k contributions are never tax-deductible — but it does require a specific entry on the W-2 itself.

Reporting for Partnerships (Schedule K-1)

If your self-employed business is a partnership, or an LLC taxed as a partnership, you’ll first need to determine your earned income for Solo 401k contribution purposes by referring to Schedule K-1, Line 14, Code A — the self-employment income line. That figure, once you subtract one-half of self-employment income tax, is what gets plugged into the Solo 401k online contribution calculator.

Where Partnership Contributions Get Reported

Contribution Type Where It’s Reported
Employee & employer pre-tax contributions BOTH: Schedule 1, Line 16 (personal Form 1040) AND Schedule K-1, Line 13, Code R
Employee Roth contribution Not reported on the tax return
Employer Roth contribution Deductible on Schedule 1, Line 16 AND Schedule K-1, Line 13, Code R — but also taxable in-plan conversion on Form 1099-R, Lines 5a/5b

ℹ️ Partnerships Report Contributions in TWO Places

Unlike a sole proprietorship, employee and employer pre-tax Solo 401k contributions for a partnership business must be reported in two separate places: Schedule 1, Line 16 of your personal Form 1040, and Schedule K-1, Line 13, using Code R. My Solo 401k Financial notes that you can find more detail on this in IRS Publication 560, page 15, under the section titled “Where to Deduct Contributions.”

Are Solo 401k Contributions Reported on Form 5498?

A question My Solo 401k Financial hears often: are Solo 401k contributions reported on Form 5498? The answer is no.

⚠️ Form 5498 Is for IRAs Only — There’s No Such Thing as a “Solo IRA”

Form 5498 is used for IRAs — traditional IRAs, Roth IRAs, SEP IRAs. It is not used for Solo 401k plans. IRA custodians use Form 5498 to report contributions, rollovers, Roth conversions, and year-end fair market value. A Solo 401k is not an IRA. My Solo 401k Financial often hears people refer to a “solo IRA” when they actually mean a Solo 401k — but there’s no such thing as a solo IRA. You can have a Solo 401k, you can have an IRA, and you can even have both at the same time, but they are two entirely separate account types with separate reporting rules.

How Should You Keep Records of Your Contributions?

A frequent question: what should a Solo 401k owner keep for records when making contributions? The Solo 401k holding accounts — also known as bank or brokerage accounts — are used to track contributions and indirectly report them. That’s the entire purpose of having separate holding accounts for pre-tax Solo 401k funds, Roth Solo 401k funds, and voluntary after-tax Solo 401k funds.

Plan Setup Number of Holding Accounts
One-participant plan 3 — pre-tax, Roth, and voluntary after-tax buckets
Two-participant plan (e.g., both spouses self-employed) 6 — each participant has their own pre-tax, Roth, and voluntary after-tax bucket

ℹ️ It’s Still Just One Plan

Even with three or six separate holding accounts, it’s considered just one Solo 401k plan — not three or six separate plans. You’re simply required to track each contribution source separately. That’s how you indirectly record-keep your contributions: through those separate brokerage or bank accounts, combined with reporting on your personal and/or business tax return depending on the contribution type. You don’t need to report this information to My Solo 401k Financial unless they request it when preparing Form 5500-EZ.

When Does Form 5500-EZ Come Into Play?

Form 5500-EZ can also be used to report contributions — but it’s important to understand that this is not for reporting to the IRS for tax deduction purposes. It’s strictly for informational reporting.

Question Answer
When does Form 5500-EZ apply? When the market value of the entire plan (all assets, cash, and holding accounts combined — pre-tax, Roth, and voluntary after-tax) exceeds $250,000
Are contributions reported on it? Yes, but only if you’re already required to file the return in the first place
What if I also have a defined benefit plan? If the combined, aggregated value of the defined benefit plan and the Solo 401k exceeds $250,000, you must file a separate Form 5500-EZ for each plan

💡 Two Plans, Two Separate Filings

If you have both a defined benefit plan and a Solo 401k for your self-employed business, and the aggregate value of both plans exceeds $250,000, you’ll need to file a separate Form 5500-EZ for each plan — one for the defined benefit plan, and one for the Solo 401k plan. My Solo 401k Financial will file and prepare Form 5500-EZ for clients, as long as you timely request it through their online Form 5500-EZ request form on the Forms tab of their website. They don’t have access to client funds, so it’s your responsibility to notify them in a timely fashion.

Reporting vs. Deposits: Why the Year Matters

An important distinction: you need to report contributions based on the tax year they’re made for, not necessarily the calendar year you actually deposit them. If you already had a Solo 401k plan open by December 31st of last year, you have until your business tax return due date plus any timely filed extension this year to make all contribution types — employee, employer, and voluntary after-tax — for last year’s tax year.

ℹ️ Common Sense, But Frequently Misunderstood

Even if you’re physically making the contribution in 2026, if it’s designated for tax year 2025, you must report it on your 2025 tax return — not your 2026 tax return. My Solo 401k Financial notes that this sounds like common sense, but they get questions about it quite often.

Common Mistakes to Avoid

Mistake What to Remember
Double reporting contributions Don’t report the same contribution in multiple places where only one is required
Forgetting Roth isn’t deductible Employee Roth Solo 401k contributions are never tax-deductible
Confusing employer Roth treatment Deductible on the business return, but taxable on the personal return as an in-plan conversion
Missing deadlines If your plan was opened by Dec. 31 of the prior year, you generally have until this year’s business tax filing deadline (plus extensions) to fund last year’s contributions

⚠️ Haven’t Opened a Plan Yet? You May Still Have Options

If you have not yet opened a Solo 401k plan, you may still have time to open one in the current year and make prior-year contributions — but generally only employer contributions and voluntary after-tax contributions would be available for that prior tax year, not employee salary deferral contributions (which typically require the plan to have been established by December 31st of that tax year).

Key Takeaways: Solo 401k Contribution Reporting

Topic Key Point
Reporting depends on Both contribution type AND business entity structure
Sole proprietorship Schedule C Line 31 → Schedule 1, Line 16 for pre-tax; Roth not reported
S-Corp / C-Corp W-2 Box 1 wages → Form 1120-S/1120 for employer contributions; W-2 Box 12 for employee Roth
Partnership Schedule K-1, Line 14 Code A → reported in TWO places: Schedule 1, Line 16 AND Schedule K-1, Line 13, Code R
Voluntary after-tax / Mega Backdoor Roth Not on your tax return — reported on Form 1099-R, Box 5, upon conversion
Employer Roth contributions Deductible on the business return, but taxable as an in-plan conversion on Form 1099-R and your personal Form 1040
Form 5498 Never used for Solo 401k plans — it’s exclusively for IRAs
Form 5500-EZ Informational only; required once plan market value exceeds $250,000
Record-keeping Tracked through separate pre-tax, Roth, and voluntary after-tax holding accounts

Need Help Reporting Your Solo 401k Contributions?

Whether you need to calculate your contribution amount, complete a Mega Backdoor Roth conversion form, or request a Form 5500-EZ filing, My Solo 401k Financial is here to help you stay compliant and maximize your retirement savings.

Next Steps:

Open a Solo 401k Account Today
|
Visit My Solo 401k Financial

Remember: This information is provided for educational purposes only. Always consult with qualified tax, legal, and investment professionals before making investment decisions with your retirement funds.

 

Can a Solo 401k be SAFE HARBOR?

Can a Solo 401k be SAFE HARBOR?

This is a question My Solo 401k Financial hears regularly, especially from prospective Solo 401k clients: can a Solo 401k be a safe harbor plan? The short answer is no — and understanding exactly why reveals some important truths about how a Solo 401k is fundamentally different from a traditional, full-time employer 401k plan. This guide breaks down the safe harbor rules, why they don’t apply to owner-only businesses, and what self-employed individuals need to know if they ever hire employees.

Watch: My Solo 401k Financial explains why a Solo 401k can never be a safe harbor plan

The Short Answer: No, a Solo 401k Cannot Be Safe Harbor

A Solo 401k plan is designed for a self-employed business owner or owner-only businesses with no full-time, non-owner common-law W-2 employees who work 1,000 hours or more in the business. Because of this fundamental design, a Solo 401k simply is not — and should never be structured as — a safe harbor plan.

ℹ️ Why This Comes Down to Who the Plan Covers

Whether a plan can be safe harbor comes down to one key question: does the plan cover common-law employees who need to be protected from unfair treatment, or is it strictly for the business owner(s) and their spouse(s)? A true Solo 401k, such as one offered by My Solo 401k Financial, falls into the second category — which is exactly why safe harbor rules don’t apply.

Who Can Be Excluded When Opening a Solo 401k?

When opening a Solo 401k plan, you can always exclude certain categories of workers from eligibility — which is part of why the plan stays in “owner-only” territory:

Worker Type Can Be Excluded?
1099 contractors ✅ Always — regardless of hours worked
W-2 employees working under 1,000 hours/year ✅ Yes — part-time employees under the threshold
Employees under age 21 ✅ Always — regardless of hours
Non-owner spouse working in the business ❌ Cannot disqualify the plan — spouse may participate

Who Can Participate in a Solo 401k?

From an eligibility perspective, a Solo 401k plan is for owner-only businesses and their respective spouses. A business may have multiple owners, and both owners don’t necessarily have to participate in the plan — but they would each be eligible to participate. A spouse can also participate in the plan, even if he or she is not an owner of the business — they simply need to be working in the same self-employed business and earning income from it.

What Is a Safe Harbor 401k, and Who Is It For?

Safe harbor 401k rules are designed for traditional, full-time employer 401k plans. Think of working for a large company like Microsoft, Best Buy, or the Coca-Cola Company — chances are, that employer’s 401k plan may be structured as a safe harbor plan.

That’s because traditional employer plans cover common-law W-2 employees — meaning non-owner employees. The government wants to ensure that a full-time employer plan does not unfairly benefit the business owners, officers, or highly compensated employees of the corporation sponsoring that plan.

⚠️ Safe Harbor Status Is Not Just a Label

One important point regarding safe harbor status: it’s not merely a label you can elect for marketing purposes. If a full-time employer 401k elects safe harbor status, it results in required contributions — typically mandatory employer contributions that must actually be funded for eligible employees.

Common Safe Harbor Contribution Formulas

Formula Description
Required employer matching contribution The employer matches a portion of eligible employee deferrals
Required employer non-elective contribution Often structured as a profit-sharing contribution made to all eligible employees, regardless of whether they defer
Qualified Automatic Contribution Arrangement (QACA) A specific type of automatic-enrollment safe harbor formula, often called a “QACA safe harbor”

ℹ️ Vesting and Notice Rules Apply Too

These safe harbor contributions are required for eligible employees and are typically subject to specific vesting and notice rules. This is all part of an important plan design consideration for a full-time employer 401k with common-law employees — but it has no bearing whatsoever on a true owner-only Solo 401k.

Why Safe Harbor Exists: Avoiding Non-Discrimination Testing

To make sure a full-time employer plan doesn’t unfairly favor owners and highly compensated employees, many traditional 401k plans are subject to annual non-discrimination testing. Safe harbor status helps the employer avoid the headaches of this testing by requiring certain mandatory contributions to eligible employees.

Types of Non-Discrimination Testing

Testing Type What It Measures
ADP Testing Looks at employee elective deferrals — comparing highly compensated employees against rank-and-file employees
ACP Testing Looks at matching contributions made to employees
Top-Heavy Testing Looks at whether too much of the plan balance is concentrated among owners and key employees

💡 Why This Doesn’t Apply to a True Solo 401k

Because a Solo 401k cannot be used by non-owner employees (with the exception of a working spouse), there is no group of rank-and-file employees to compare against the owner. For this reason, a Solo 401k is not subject to non-discrimination testing — meaning the owner doesn’t need a safe harbor formula in the first place, since there’s nothing to test against. This is one of the simplifying advantages of operating a true owner-only Solo 401k.

Solo 401k vs. Safe Harbor 401k: The Key Difference

There’s really one key difference between a Solo 401k and a safe harbor 401k: the type of business each plan is designed for.

Feature Solo 401k Safe Harbor 401k
Designed for Owner-only businesses with no full-time non-owner employees Full-time employers with common-law W-2 employees
Non-discrimination testing Not subject — no rank-and-file employees to compare Subject to ADP/ACP/top-heavy testing unless safe harbor elected
Required contributions None required — fully discretionary by the owner Mandatory matching, non-elective, or QACA contributions
Contribution limits High contribution limits for the owner(s) Governed by overall plan and testing rules
Roth / Mega Backdoor Roth options Yes — including voluntary after-tax Mega Backdoor Roth Solo 401k contributions Varies by plan design
Participant loans Available, depending on plan document Available, depending on plan document
Alternative investments Real estate, promissory notes, precious metals, cryptocurrency, private equity, trust deeds, and more Typically limited to equities/mutual funds offered by the plan provider

💡 My Solo 401k Financial: A Pioneer in the Mega Backdoor Roth Solo 401k

My Solo 401k Financial notes that a true Solo 401k — like the one they offer — is designed to give business owners high contribution limits, Roth options, and the ability to make Mega Backdoor Roth Solo 401k contributions through voluntary after-tax Solo 401k contributions. In fact, My Solo 401k Financial was the first in the industry to offer the Mega Backdoor Roth Solo 401k and has processed thousands of Mega Backdoor Roth Solo 401k conversions for clients — all without the complexities of a traditional full-time employer 401k plan.

A Simple Way to Remember the Difference

In short: Solo 401k means an owner-only retirement plan. Safe harbor 401k means an employee-inclusive 401k design that helps satisfy testing rules for full-time employer 401k plans.

What If Your Self-Employed Business Hires Employees?

This is a question My Solo 401k Financial gets often: what if my self-employed business hires part-time or full-time employees after I’ve already opened my Solo 401k? This requires careful, ongoing review.

ℹ️ You Can Open a Solo 401k Even with Part-Time Hires

You can open a Solo 401k plan even if you have full-time W-2 employees who work under 1,000 hours. The eligibility concern arises specifically from an ongoing perspective — meaning you have to keep monitoring employee hours and tenure over time, even after the plan is already established.

Two Key Employee Thresholds to Watch

Scenario Threshold Required Action
Full-time hire, age 21+ 1,000+ hours in 12 consecutive months Must close the Solo 401k plan
Long-term part-time employee 500–999 hours for two consecutive 12-month periods Must close the Solo 401k, transfer to an IRA, or convert to a full-time employer 401k (with the option of safe harbor)

⚠️ The Long-Term Part-Time Employee Rule

If you hire a part-time W-2 employee after opening your Solo 401k plan, and that individual works two consecutive 12-month periods with hours falling between 500 and 999 hours each period, that individual may be considered a long-term part-time employee. This requires you to close the Solo 401k plan, transfer it to an IRA, or convert it to a full-time employer 401k — with the option to also convert that new plan into a safe harbor plan if it makes sense for the business going forward.

Bottom Line on Ongoing Eligibility

If your self-employed business does not have any full-time W-2 employees, and does not have any common-law W-2 employees who work between 500 and 999 hours over two consecutive 12-month periods, then you don’t have to worry about safe harbor rules at all — your Solo 401k remains a true owner-only plan.

Key Takeaways: Solo 401k and Safe Harbor Rules

Topic Key Point
Can a Solo 401k be safe harbor? No — never. A Solo 401k is for owner-only businesses, and safe harbor is for full-time employer plans with common-law employees
Who can participate Business owner(s) and their working spouse(s) — non-owner full-time employees disqualify the plan
Non-discrimination testing Not applicable to a Solo 401k — there’s no rank-and-file employee group to test against
Safe harbor contributions Mandatory employer matching, non-elective, or QACA contributions — only relevant to full-time employer plans
Hiring full-time employees 1,000+ hours in 12 months requires closing the Solo 401k
Hiring part-time employees 500–999 hours over two consecutive years triggers the long-term part-time employee rule
Mega Backdoor Roth Available in a true Solo 401k — My Solo 401k Financial pioneered this strategy in the industry

Ready to Open a True Owner-Only Solo 401k?

Whether you’re just starting out as a self-employed business owner, planning to bring on a spouse, or simply want to understand how Solo 401k eligibility works as your business grows, My Solo 401k Financial can help you set up a plan with maximum flexibility — including the Mega Backdoor Roth strategy, participant loans, and alternative investments.

Next Steps:

Open a Solo 401k Account Today
|
Visit My Solo 401k Financial

Remember: This information is provided for educational purposes only. Always consult with qualified tax, legal, and investment professionals before making investment decisions with your retirement funds.

 

Does a Promissory Note NEED an Interest Rate?

Does a Promissory Note NEED an Interest Rate?

If you’re considering a promissory note investment inside your Solo 401k or self-directed IRA, one question comes up again and again: does the note actually need to charge interest? This guide answers that question directly — and covers everything else you need to know about structuring a compliant promissory note, setting a fair interest rate, avoiding usury law violations, and staying clear of prohibited transactions.

Watch: My Solo 401k Financial explains why a promissory note must always charge a fair interest rate

The Short Answer: Yes, a Promissory Note Must Charge Interest

Promissory notes are one of the most common ways to document a private investment — also known as a private loan — where a Solo 401k makes an investment in a third party. Whether the promissory note investment is made through a self-directed Solo 401k or a self-directed IRA, the answer to “does a promissory note need an interest rate?” is a clear yes.

⚠️ The Interest Rate Cannot Be Zero

The interest rate listed on a promissory note cannot be zero. If you invest in a promissory note and charge zero interest, that investment is not going to benefit the Solo 401k plan — and benefiting the plan is the entire point of making the investment in the first place.

Why the Plan Must Benefit from Every Investment

Anytime you invest Solo 401k funds — whether in equities, real estate, or promissory notes — it has to be done with the intention of growing the retirement plan. Congress created retirement plans, including Solo 401k plans, specifically so individuals could save for retirement. If you don’t charge a fair interest rate that benefits the plan, the plan simply won’t grow, defeating the entire purpose of the investment.

ℹ️ The Plan Must Benefit — Not the Borrower

A promissory note investment should be made with the intent of growing the Solo 401k plan — not necessarily to help the borrower. Of course, the borrower is helped indirectly by being able to access financing. But the interest rate charged needs to reflect what return the Solo 401k will earn — not be set artificially low as a favor to the borrower.

What Exactly Is a Promissory Note?

A promissory note is a promise by a borrower to repay money to a lender — in this case, the lender is the Solo 401k plan. It is a written instrument that acts as evidence of the investment and outlines the payment terms.

Required Elements of a Promissory Note

The promissory note must be drafted accordingly and include all of the following pertinent information:

Element Details
Lender / Beneficiary The Solo 401k plan, listed by name
Borrower Name of the individual or company (e.g., hard money lender, construction company) — as long as not a disqualified party
Principal loan amount The total amount being loaned to the borrower
Interest rate Must be listed and cannot be zero
Repayment schedule Monthly, quarterly, or annual — your choice, but it must be outlined
Maturity date The date the loan must be repaid in full
Secured or unsecured Whether collateral backs the note
Default provisions What happens if the borrower fails to pay

💡 Sample Promissory Note Available

My Solo 401k Financial provides a sample promissory note on the Forms tab of their website that you can use as a starting point when drafting your own note. As the trustee of the plan, you’ll also want to sign the promissory note and put together a clear payment schedule outlining the amount of each payment and when it’s due.

Don’t Confuse a Promissory Note Investment with a Participant Loan

It’s important not to confuse a promissory note investment with a Solo 401k participant loan. They are entirely different concepts:

Feature Participant Loan Promissory Note Investment
Who borrows You, the plan participant/trustee An unrelated third party
Can it go to family? N/A — it’s your own plan No — cannot be you, your spouse, parents, or children

How Do You Determine the Right Interest Rate?

You typically want to charge an interest rate based on the borrower’s credit history. If the borrower has good credit, the interest rate should generally be lower than for a borrower with poor credit — because the odds of the note going into default increase as creditworthiness decreases.

Factors to Consider When Setting an Interest Rate

Factor Why It Matters
Borrower’s creditworthiness Better credit generally warrants a lower rate; weaker credit warrants a higher rate to compensate for risk
Secured vs. unsecured Unsecured notes typically carry higher rates since there’s no collateral to fall back on
Collateral value Higher-value, more liquid collateral can support a lower rate
Market interest rates The note should reflect a return competitive with prevailing market conditions
Risk of default Higher perceived risk should be compensated with a higher rate
Business vs. individual borrower Business borrowers may carry different risk profiles than individuals
Loan-to-value ratio A lower loan-to-value ratio (more collateral relative to loan size) supports a lower rate
State usury laws The rate must comply with the legal maximum in the applicable state

💡 Typical Interest Rate Range

A typical interest rate charged on a promissory note generally falls between 8% and 15% — especially for unsecured notes. This range has even been seen applied to secured promissory notes in some cases. As always, a reasonable rate depends on the specific facts and circumstances of each individual loan.

Don’t Break Usury Laws — There’s a Ceiling Too

While the interest rate cannot be zero, it also cannot be set too high. You need to make sure you don’t break any usury laws, which are driven by your state of residence.

⚠️ Charging Too Much Interest Can Also Be a Problem

If you charge, for example, a 20% interest rate on a promissory note to an individual or business with good credit, state usury laws could come into play and flag that rate as excessive. The interest rate must be reasonable in light of the borrower’s risk profile — charging an unreasonably high rate just because you can isn’t a safe approach, and it can run afoul of your state’s usury limit.

How Must the Funds Flow? Critical Compliance Rules

Once you’ve documented the promissory note investment in writing, the funds need to be wired directly from the Solo 401k holding account to the borrower. This is a critical compliance point that My Solo 401k Financial emphasizes repeatedly.

Fund Flow Direction Correct or Incorrect?
Solo 401k holding account → directly to borrower’s bank account ✅ Correct
Solo 401k holding account → your personal or business bank account → borrower ❌ Incorrect — treated as a taxable distribution
Borrower’s payments → directly to Solo 401k holding account ✅ Correct
Borrower’s payments → your personal account → Solo 401k ❌ Incorrect

⚠️ Funds Cannot Pass Through Your Personal or Business Account

It cannot be wired first to your business or personal bank account on the way to the borrower. If that happens, it will be treated as a taxable distribution — even if the funds eventually reach the borrower as intended. The flow of funds must go directly to the borrower’s bank account, with no detour through your own accounts.

ℹ️ Receiving Payments by Check

If the borrower makes a payment by check, they can mail the check made payable in the name of the Solo 401k, addressed to you as trustee. You then deposit those funds into the Solo 401k bank or brokerage account. As long as the payments flow directly to the Solo 401k holding account, they maintain their tax-deferred status — growing tax-deferred so you can reinvest those funds within the plan.

Can You Lend to a Family Member? Disqualified Person Rules

This is a special area of concern under the prohibited transaction regulations. You cannot invest in a promissory note to a family member — even if the Solo 401k plan receives a favorable interest rate and the note is fully and properly documented.

Who Is a Disqualified Person?

Person / Entity Disqualified?
The Solo 401k participant (you) ✅ Yes
Your spouse ✅ Yes
Your parents and grandparents ✅ Yes
Your children and grandchildren ✅ Yes
Any business you own or control ✅ Yes
An unrelated friend’s business (where you are not an employee or owner) ✅ Permitted

⚠️ Even Helping Your Child Buy a Home Doesn’t Qualify

A Solo 401k cannot invest in a promissory note to your child — even at a market interest rate, even if fully documented, and even if your intention is simply to help your child with their first home purchase. Unfortunately, this type of transaction is not allowed and would constitute a prohibited transaction.

💡 Lending to an Unrelated Friend’s Business Is Allowed

By contrast, a Solo 401k can invest in a promissory note to an unrelated friend’s business. For example, if a friend has a business and approaches you for financing, you can invest your Solo 401k funds in a promissory note to that friend’s business — as long as you are not an employee or owner of that business. You’ll still want to document the note properly and charge an interest rate that benefits the plan.

How Can a Promissory Note Be Structured?

A Solo 401k promissory note can be structured in different ways, and you get to decide what works best for your situation:

Structure Option Description
Interest-only with balloon payment Fixed interest-only payments throughout the term, with the full principal due as a final balloon payment
Principal and interest Regular payments that include both principal and interest throughout the loan term

You can also decide how often payments are made — monthly, quarterly, or annually — and that schedule needs to be clearly outlined on the promissory note itself.

💡 Example: A Properly Structured Promissory Note

Suppose a Solo 401k plan invests in a promissory note worth $100,000 to an unrelated party. The note lists the principal amount of $100,000, along with the agreed-upon interest rate. The funds flow from the Solo 401k bank or brokerage account directly to the borrower, and the borrower then makes payments directly back to the Solo 401k plan. This type of structure is very common because the Solo 401k receives a stated, predictable return and all loan terms are clearly documented in writing.

Key Takeaways: Promissory Notes and Interest Rates

Topic Key Point
Does it need interest? Yes — the rate cannot be zero; it must benefit the Solo 401k plan
How to set the rate Based on borrower creditworthiness, collateral, loan-to-value, and market conditions
Typical range Generally 8%–15%, especially for unsecured notes
Rate ceiling Must comply with state usury laws — too high a rate can be a legal violation
Fund flow Must go directly between the Solo 401k and the borrower — never through your personal/business accounts
Who can’t borrow You, your spouse, parents, grandparents, children, grandchildren, or any business you control
Documentation Must be a signed, written instrument outlining all key terms
Structure options Interest-only with balloon, or principal + interest; monthly, quarterly, or annual payments

Ready to Structure Your Solo 401k Promissory Note Correctly?

Whether you need a sample promissory note template, guidance on setting a compliant interest rate, or help opening a self-directed Solo 401k that allows promissory note investments, My Solo 401k Financial is here to help.

Next Steps:

Open a Solo 401k Account Today
|
Visit My Solo 401k Financial

Remember: This information is provided for educational purposes only. Always consult with qualified tax, legal, and investment professionals before making investment decisions with your retirement funds.

 

Does Fidelity Allow 401k Loans?

Does Fidelity Allow 401k Loans?

Watch: How solopreneurs unlock Solo 401k participant loans by restating their Fidelity plan documents

Short answer: Fidelity’s basic Solo 401k plan does not allow 401k participant loans.
But that doesn’t mean you’re stuck. If you already hold a basic Fidelity Solo 401k — or you’re
comparing your options before opening one — you can upgrade (“restate”) your plan documents to those
provided by My Solo 401k Financial and unlock participant loans, the
Mega Backdoor Roth, alternative investments, and SECURE Act tax credits —
all while keeping your account right where it is at Fidelity.

Below is the comparative blueprint: why Fidelity’s basic plan blocks loans, how a restatement resolves it, and the
exact process to fund and execute your Solo 401k participant loan.

Key takeaway: A restatement is not a new plan and it does not shut down your existing plan.
Your plan simply continues — now governed by IRS-approved documents that enable Solo 401k loans, the
Mega Backdoor Roth, and more.

First, Are You Eligible for a Solo 401k?

Before discussing loans, start with eligibility. A Solo 401k — also called a one-participant
plan or owner-only plan — comes down to two fundamental requirements:

1. Self-Employment Income

You must report earned self-employment income on your taxes. How you report it depends on your entity type:

Business Tax Treatment Where the Income Is Reported
Sole Proprietor Schedule C earned self-employment income
S-Corp or C-Corp W-2 wages from the business
Partnership Line 14 of the K-1 you receive from the business

2. No Full-Time Non-Owner, Non-Spouse W-2 Employees

You cannot have any non-owner, non-spouse, full-time W-2 employees working for any business owned by you or your
spouse. For this purpose, a full-time W-2 employee is one working 1,000 hours per year with a year of
service, or 500 hours per year for two consecutive years.

Example: You and your spouse can both work in the business as W-2 employees and still qualify.
Only a non-owner, non-spouse full-time W-2 employee would prevent a solopreneur from establishing a Solo 401k.

Why Fidelity’s Basic Plan Blocks 401k Loans

Being eligible lets you open a Solo 401k — but there are big differences between the basic plans
offered by discount brokerages like Fidelity and an individually designed Solo 401k offered by
My Solo 401k Financial. Fidelity’s basic prototype plan documents simply don’t allow many of the
advanced features.

Feature Fidelity Basic Plan My Solo 401k Financial
Participant (401k) Loans Not Allowed Allowed
Alternative Investments (real estate, crypto) Not Allowed Allowed
Mega Backdoor Roth Contributions Not Allowed Allowed
In-Plan Roth Conversions Not Allowed Allowed
$1,500 in SECURE Act Tax Credits Not Allowed Allowed
Form 5500-EZ Filing Support Not Provided Included

The Fix: Restate Your Plan Documents

You’re not stuck with those basic Fidelity documents. The process to upgrade is called a restatement.
Importantly:

  • You are not setting up a second plan.
  • You are not shutting down your Fidelity plan and starting over.
  • Your plan continues — now governed by My Solo 401k Financial’s IRS-approved documents.

Those upgraded documents enable Solo 401k loans, Mega Backdoor Roth contributions, alternative
investments, and the ability to claim SECURE Act tax credits. Want the deeper mechanics on after-tax dollars? See our
detailed guide on the
Mega Backdoor Roth using a Solo 401k plan.

How the Process Works

  1. Replace the documents. We prepare your restated documents to upgrade your plan within the same business day when you sign up.
  2. Open new accounts. You’ll open new accounts — which can stay at Fidelity. These are called non-prototype or investment-only accounts, used by Fidelity for people who bring their own plan documents. We help you open them as part of onboarding.
  3. Transfer cash and assets. Move the cash and assets from your existing basic plan into the new accounts governed by the upgraded documents. Assets can transfer in kind — you don’t have to sell your investments.
Important: From Fidelity’s perspective, your existing account is still governed by their plan
documents. That’s why you open the new non-prototype account — moving the assets there is how Fidelity recognizes
your plan is now governed by My Solo 401k Financial’s documents.

Solo 401k Loan Rules at a Glance

A Solo 401k loan lets the solopreneur access money in their Solo 401k — for any purpose —
without taxes or penalties, as long as the loan stays within the required terms and is paid back on schedule. We prepare
all the required loan documents.

Loan Term Detail
Maximum Amount 50% of the balance, not to exceed $50,000
Interest Rate Prime plus 1% — or a comparable CD rate plus 2%
Repayment Term 5 years (longer if used to purchase your primary residence)
Payment Frequency Monthly or quarterly — equal payments of principal and interest
Prepayment Allowed early with no penalty
Repaid To The same Fidelity account from which the funds were withdrawn
Example: With $120,000 in your Solo 401k, you can borrow the full $50,000. With $60,000 in the account,
you could borrow up to $30,000 (50% of the balance).

Hassle-Free Document Preparation

When you let us know you want to take a loan, we prepare the amortization schedule and all required loan documents —
in one business day. You then repay according to the schedule, with the option to prepay early
with no penalty, back into the same account from which the funds were withdrawn.

Flat Fees and SECURE Act Tax Credits

My Solo 401k Financial charges a flat fee regardless of your account value: $650 initial cost
(a $525 establishment fee plus the first $125 annual fee), then a $125 annual fee starting twelve months
later. That covers ongoing support — including preparing required loan documents and electronic Form 5500-EZ filing
for clients who notify us in a timely fashion.

We were the first provider to offer a Solo 401k plan enabling Mega Backdoor Roth contributions, and the
first to enable solopreneurs to claim tax credits under the SECURE Act: $500 per year for three
consecutive years
($1,500 total). Because it’s a tax credit — a dollar-for-dollar reduction in tax
liability, not just a deduction — it more than covers our fees for the first seven years.

Did you know? Even added up across the first seven years, the flat fees wouldn’t amount to the full $1,500
in available SECURE Act tax credits. Learn more about how an individually designed
Solo 401k plan works.

Ready to Unlock 401k Loans in Your Fidelity Solo 401k?

Whether you already have a basic Fidelity plan or you’re just getting started, My Solo 401k Financial can
restate your documents — often the same business day — so you can take a Solo 401k loan, make
Mega Backdoor Roth contributions, and invest in alternative assets.

Next Steps:
Get Started Today!

Remember: This information is provided for educational purposes only. Always consult with qualified tax,
legal, and investment professionals before making decisions with your retirement funds.

2026 Solo 401k Contribution Limits by Age

2026 Solo 401k Contribution Limits by Age

Watch: My Solo 401k Financial breaks down the 2026 Solo 401k contribution limits by age

If you are a high-income business owner or solopreneur, the Solo 401k offers the highest contribution limits of any defined contribution plan available to the self-employed. The reason is simple: in the words of the IRS, you are both the employee and the employer, which gives you access to multiple contribution buckets and total control over how much you set aside.

Below is a complete breakdown of the 2026 Solo 401k contribution limits by age, including employee deferrals, employer contributions, catch-up and super catch-up contributions, the overall limit, and how the Mega Backdoor Roth strategy unlocks far more Roth savings than a standard Roth IRA.

Who Is Eligible for a Solo 401k?
A Solo 401k is an owner-only plan. You qualify if you meet both of these requirements:

  • You are self-employed — reporting earned self-employment income (Schedule C for a sole proprietorship, W-2 wages for an S-corp or C-corp, or line 14 of a K-1 from a partnership).
  • You have no non-owner, non-spouse full-time W-2 employees working for any business owned by you or your spouse. Full-time generally means an employee age 21+ working 1,000+ hours in a year, or 500+ hours for two consecutive years.

The Three Contribution Buckets

An advanced Solo 401k plan — like the one offered by My Solo 401k Financial — gives you three ways to contribute:

1. Employee Contributions

Also called salary deferrals, these can be made pre-tax or Roth and are subject to the annual employee deferral limit (plus catch-up contributions if you are age 50+).

2. Employer (Profit-Sharing) Contributions

Because you are also the employer, you control these contributions — unlike a 401k at a day job, where employer contributions are typically discretionary.

3. Voluntary After-Tax Contributions

This third bucket is the foundation of the Mega Backdoor Roth strategy. You first make a voluntary after-tax contribution, then transfer those dollars to a Roth Solo 401k or a Roth IRA.

2026 Solo 401k Contribution Limits by Age

The table below shows how the 2026 Solo 401k contribution limits change with age. Catch-up and super catch-up contributions are above and beyond the overall §415(c) annual additions limit.

Age Group (as of end of 2026) Employee Deferral Catch-Up Total Employee Limit Overall Total Limit
Under Age 50 $24,500 — $24,500 $72,000
Age 50–59 (and 64+) $24,500 $8,000 $32,500 $80,000
Age 60–63 (super catch-up) $24,500 $11,250 $35,750 $83,250

Figures assume sufficient self-employment compensation to justify the contributions. The overall limit reflects the §415(c) annual additions limit plus applicable catch-up contributions.

Under Age 50

For 2026, the employee deferral limit is $24,500, and the overall §415(c) annual additions limit (employee + employer + voluntary after-tax) is $72,000.

Age 50 and Older (But Not 60–63)

Once you reach age 50, you can make an additional $8,000 catch-up contribution. This is a type of employee contribution, made directly to either the pre-tax or the Roth account. That brings the employee limit to $32,500 and the overall total to $80,000.

Example: A 55-year-old solopreneur with ample self-employment income could defer $24,500 as an employee contribution, add the $8,000 catch-up, and use employer and voluntary after-tax contributions to reach the $80,000 overall total for 2026.

Age 60 to 63 — The Super Catch-Up

Thanks to the SECURE Act 2.0, individuals who are age 60 to 63 as of the end of 2026 can make a larger super catch-up contribution of $11,250 instead of $8,000. This raises the employee limit to $35,750 and the overall total to $83,250.

Important — Roth Catch-Up Rule for High Earners: Under the SECURE Act 2.0 “Rothification” rule, high earners with more than $150,000 in W-2 wages for the prior year (2025) must designate their catch-up contributions as Roth — they cannot make them pre-tax. This applies specifically to W-2 wages (box 3). If your business is taxed as a sole proprietorship or partnership and you do not pay yourself W-2 wages, you are not forced into Roth catch-up contributions, even if your self-employment compensation exceeds $150,000.  Please see https://mysolo401k.net/mycommunity/mandatory-roth-solo-401k-catch-up-contributions-begin-in-2026-what-self-employed-individuals-and-employers-need-to-know/

Mega Backdoor Roth: Supersize Your Roth Savings

The voluntary after-tax limit is dramatically higher than standard Roth limits. For 2026, a solopreneur with a plan that allows voluntary after-tax contributions can contribute 100% of self-employment compensation up to $72,000 as a voluntary after-tax contribution, then transfer those dollars to a Roth Solo 401k or a Roth IRA. That is almost ten times the $7,500 Roth IRA limit for 2026.

This two-step process — voluntary after-tax contribution followed by a transfer to a Roth account — is the Mega Backdoor Roth strategy. If you are age 50+ and want your catch-up dollars to be Roth, note that those go directly to the Roth account rather than through the after-tax bucket.

Day Job 401k + Solo 401k Side Hustle: How the Limits Interact

Many people have a day job 401k and a Solo 401k for a side business. Here is the general rule:

Employee Contributions Aggregate Per Person

The employee deferral limit (including catch-up contributions) applies at the person level. If you max out employee contributions at your day job, you cannot make additional employee contributions to your Solo 401k.

Employer & Voluntary After-Tax Apply Per Plan

Even if you’ve maxed out employee deferrals at day job 401k plan, you can still make employer and voluntary after-tax contributions to your Solo 401k. The $72,000 overall limit applies at the plan level and is not reduced by contributions to a day job 401k.

Example: You have a 401k at your day job and at least $72,000 of self-employment compensation. With a Solo 401k that allows voluntary after-tax contributions, you could still make a $72,000 voluntary after-tax contribution to the Solo 401k and transfer it to a Roth account — a full Mega Backdoor Roth.

The 403(b) Exception: If your day job plan is a 403(b) rather than a 401k, the rules are stricter. All contributions to the 403(b) — employee and employer — combine with your Solo 401k contributions and together cannot exceed the overall limit. This is because the participant is deemed to control their own 403(b).

Ready to Maximize Your 2026 Solo 401k Contributions?

Whether you’re aiming for the full $72,000 overall limit, the $11,250 super catch-up, or a Mega Backdoor Roth, My Solo 401k Financial can help you set up the right plan.

Next Steps: Get Started Today!

Remember: This information is provided for educational purposes only. Always consult with qualified tax, legal, and investment professionals before making decisions with your retirement funds.

Can TWO Business Owners Open a SOLO 401k?

Can TWO Business Owners Open a SOLO 401k?

The name “Solo 401k” often leads people to assume the plan is strictly limited to a single individual. But that assumption is incorrect. This guide answers one of the most common questions self-employed business partners ask: can two business owners open and share a Solo 401k? The short answer is yes — and this post explains exactly how it works, including eligibility rules, contribution limits, separate holding accounts, and the powerful Mega Backdoor Roth Solo 401k strategy available to multi-owner businesses.

Watch: My Solo 401k Financial explains whether two business owners can open and share a Solo 401k plan

The Short Answer: Yes, Two Business Owners Can Share a Solo 401k

A Solo 401k is often described as a retirement plan for a one-person business. But what if the business has two owners? The answer is yes — two business owners may participate in the same Solo 401k plan, but only if the business does not have non-owner, full-time W-2 employees who must be covered under the plan (also known as common-law W-2 employees).

ℹ️ “Solo” Refers to the Business Type, Not the Headcount

The key to understanding this rule: Solo 401k does not always mean only one person can participate. It means the plan is for an owner-only business — and an owner-only business can have multiple owners, including a spouse-owner or spouse-employee.

Other Names for the Same Plan

A Solo 401k plan is designed for self-employed individuals or owner-only businesses. It’s often called by different names that all refer to the same plan type:

Alternate Name
Individual 401k
One-Participant 401k
Self-Employed 401k
Individual K
Solo K
Uni-K

Regardless of the name used, the Solo 401k can cover more than one person in specific situations — including a business owner and spouse, two spouses who both work in the business, two business partners, or multiple owner-employees, depending on the business structure.

Eligibility Rules for a Multi-Owner Solo 401k

As long as the business does not employ any non-owner, full-time W-2 employees who are age 21 or older and work 1,000 hours or more in the business, two (or more) owners can open a Solo 401k together.

Who Can Be Excluded from Eligibility Counts?

Worker Type Excluded from Solo 401k Eligibility Count?
1099 contractors ✅ Always excluded, regardless of hours worked
W-2 employees under age 21 ✅ Excluded, even if they work 1,000+ hours
Spouse (employee, non-owner) ✅ Excluded from disqualifying the plan — and may participate
Non-owner W-2 employee, 21+, under 1,000 hrs/year ✅ Excluded — plan remains eligible
Non-owner W-2 employee, 21+, 1,000+ hrs/year ❌ Disqualifies the plan — must be covered, which a Solo 401k cannot do

The Spousal Exception

One important exception: a spouse who is working in the business does not have to be an owner of the business in order to participate in the plan. This is known as the spousal exception, and it’s one of the most powerful planning opportunities available — allowing both spouses to maximize their own retirement contributions under the same plan.

How Are Funds Held When There Are Two Owners?

A Solo 401k is a defined contribution plan that requires separate participant accounts for each participant — and for each source of funds. Even with just one participant, the plan typically uses three separate holding accounts:

Holding Account Type Purpose
Pre-Tax Traditional pre-tax employee and employer contributions
Roth Roth Solo 401k contributions and converted funds
Voluntary After-Tax Used specifically for the Mega Backdoor Roth Solo 401k strategy

💡 Example: Two-Participant Plan = Six Holding Accounts

When two spouses (or two business partners) are both self-employed in the same business, the business sponsors one Solo 401k plan — but each participant has their own three separate holding accounts (pre-tax, Roth, and voluntary after-tax). That means a two-participant plan typically has a total of six holding accounts — three for each participant — even though it remains just one plan.

Maximizing the Mega Backdoor Roth with Two Owners

The voluntary after-tax holding account is what’s used for the Mega Backdoor Roth Solo 401k strategy. The process works in steps: you first make a voluntary after-tax Solo 401k contribution into the voluntary after-tax holding account, and then convert those funds to the Roth Solo 401k (or Roth IRA).

💡 Example: Doubling Household Mega Backdoor Roth Contributions

Both spouses (or business partners) can each make their own voluntary after-tax Solo 401k contribution into their respective holding account. If the maximum voluntary after-tax contribution for the tax year is $72,000 per person, that means both participants could each contribute $72,000 — for a combined household total of $144,000 — and then convert those amounts to their respective Roth Solo 401k funds. That’s a significant way to maximize household retirement savings using the Mega Backdoor Roth strategy across two owners in the same plan.

How Are Contributions Calculated for Each Owner?

Each owner’s contribution limit is calculated separately under the Solo 401k plan, based on that owner’s own compensation or self-employment income. The plan allows for employee contributions, employer contributions, and voluntary after-tax contributions — and one owner’s contribution amount has no impact on what the other owner can contribute.

ℹ️ One Owner Can Contribute While the Other Doesn’t

Contribution amounts are not impacted by the other owner’s contributions. In fact, in a given year, one owner may contribute to the plan while the other owner does not — both scenarios are perfectly acceptable under a single shared Solo 401k plan.

Worked Example: S Corp with Two Owners

Consider an S corporation with two business owners, each receiving W-2 wages from the business. If Owner A receives $100,000 of W-2 gross wages, here’s how their contribution would be calculated:

Contribution Type Calculation Amount
Employer profit-sharing contribution 25% × $100,000 W-2 wages $25,000
Employee contribution 2026 dollar-for-dollar maximum (not a percentage) $24,500
Total pre-tax contributions $25,000 + $24,500 $49,500

⚠️ Where Each Contribution Reduces Taxable Income

The $25,000 employer profit-sharing contribution reduces taxable income on the S corporation side, since it’s an employer contribution. The $24,500 employee contribution reduces taxable income on the personal Form 1040 tax return. In this example, the individual could still make an additional Mega Backdoor Roth Solo 401k contribution on top of these amounts, provided they have enough earned income to support it.

Because each owner’s contribution is calculated independently based on their own W-2 wages or self-employment income, two owners with different compensation levels will simply have different contribution maximums — but both remain part of the same single Solo 401k plan.

One Plan, One Fee — Even with Two Owners

A common question: if two members of the same S Corp (or domestic partners) both participate, do they need two Solo 401k plans? The answer is no — it’s considered just one Solo 401k plan.

💡 My Solo 401k Financial’s Flat-Fee Structure

Many competitors charge double the fees when there are two participants in the plan — essentially two separate setup fees, even though it’s the same business and the same plan. My Solo 401k Financial takes a different approach: when both spouses or both owners are self-employed in the same business, opening the plan results in just one fee — one plan, one annual fee — since both participants are working under that same self-employed business.

Can Each Owner Take a Participant Loan?

Yes — each owner in a multi-owner Solo 401k can take their own participant loan, but the loan amount must be calculated based on that owner’s own respective funds in the plan. Owners cannot “piggyback” off of each other’s account balances to increase their borrowing limit.

Participant Loan Feature Details
Loan basis Calculated separately, based on each owner’s own balance in the plan
Payment frequency Quarterly or monthly, fixed payments of principal and interest
Where payments go Back into the owner’s own Solo 401k bank or brokerage account
Standard term 5 years (extendable to 15 or 30 years for a primary residence purchase)
Credit check None required — you’re borrowing from your own Solo 401k plan

ℹ️ Still Just One Plan, One Fee

Even though each owner can independently access their own participant loan, the plan is still considered just one Solo 401k plan — and each owner is only being charged for that one plan. This is quite different from competitors, who will often charge all the fees associated with a two-participant plan as if it were two separate plans.

What Happens If You Hire Employees Later?

It’s important to think ahead about what happens after your Solo 401k is already established. If the business later hires employees, the first step is identifying whether those new hires are W-2 employees or 1099 contractors.

⚠️ The Long-Term Part-Time Employee Rule (Secure Act)

If a new hire is a W-2 employee who works for two consecutive 12-month periods and meets the hours threshold, the business may need to close the Solo 401k plan down. Under the Secure Act, this rule was reduced to a two-year lookback. If this situation applies to your business, you would need to close the plan — so monitoring employee hours and tenure proactively is essential for any multi-owner Solo 401k.

What If Each Owner Has a Separate Business?

Things change if each owner is self-employed in their own separate business rather than the same shared business. In that case, the two owners would generally each need to evaluate their own business for Solo 401k eligibility independently — rather than sharing one plan together.

Watch Out for Controlled Groups and Affiliated Service Groups

Before opening a Solo 401k, you must also confirm that the business is not part of a controlled group or affiliated service group — a designation that can create complications for plan eligibility across multiple businesses.

⚠️ Example: Owning Two Businesses Can Disqualify the Solo 401k

Suppose you own two businesses. Business One has two owners and no non-owner full-time W-2 employees — so on its own, it would qualify for a Solo 401k. However, if you also own Business Two, and Business Two does employ full-time W-2 employees, that can be a problem. Because of how controlled group and affiliated service group rules work, you may not be able to open a Solo 401k for Business One — even though Business One alone has no disqualifying employees — simply because Business Two has them. Anytime you’re involved in multiple businesses, pause and work with your CPA or with My Solo 401k Financial to determine eligibility before opening a plan.

Don’t Confuse Solo 401k Rules with Full-Time Employer 401k Rules

A Solo 401k is practically similar to a full-time employer 401k plan — but not in all cases, especially regarding contribution amounts, calculations, and deadlines. The contribution rules and deadlines for a Solo 401k are distinct from those governing a traditional employer-sponsored plan, so it’s important not to apply employer-plan logic directly to a Solo 401k situation.

Pre-Opening Checklist for Two Owners

Before two owners open a Solo 401k together, they should confirm the following:

Checklist Item
Both owners are owners in the business and actively working in it (have earned income)
The business does not employ any non-owner, full-time W-2 employees who are eligible
The business is not part of a controlled group or affiliated service group
The plan document includes desired features (Mega Backdoor Roth, participant loans, alternative investments)
Awareness of the $1,500 auto-contribution tax credit (separate from other startup tax credits)

ℹ️ Don’t Confuse the Auto-Contribution Credit with the Tax Credit

Many CPAs and tax professionals tend to lump the auto-contribution tax credit together with other plan startup tax credits, but they are two separate credits. The Solo 401k plan only qualifies for the auto-contribution credit — a way the government subsidizes the cost of maintaining a Solo 401k plan over time, up to $1,500. To qualify, your income generally needs to be earned income — not passive income, capital gains income, or Social Security income.

Already Have a Solo 401k? How Restatement Works

If you already have an existing Solo 401k plan — whether as a single owner or with a partner — and want to switch providers, you don’t need to start from scratch. This process is called a restatement.

What Is a Restatement?

A restatement means you simply change from your current Solo 401k provider to a new provider, such as My Solo 401k Financial. Key facts about restating a plan:

  • You can typically keep the same EIN number that was already issued for the plan
  • You can keep the same plan name
  • Because you are not closing the plan — only changing providers — a restatement does not trigger having to issue a distribution-related form
  • You will need the original plan’s effective date (found in the existing plan’s adoption agreement)

💡 Example: Restating a Solo 401k from Fidelity

My Solo 401k Financial regularly restates Solo 401k plans that currently sit at Fidelity. The process involves opening new, non-prototype, investment-only brokerage accounts at Fidelity under the My Solo 401k Financial plan, and then internally transferring the existing securities and cash from the old Fidelity Solo 401k account to the new Fidelity brokerage account. The plan can also work with other brokerage firms or banks — including Interactive Brokers, Schwab, or any institution willing to work with the plan provider.

One Plan with Maximum Flexibility

When drafting a Solo 401k plan, My Solo 401k Financial drafts it for maximum flexibility under the law — including the Mega Backdoor Roth strategy, the ability to invest in alternative investments and equities, real estate, and participant loans. Unlike providers who charge separate fees for separate features, a flat fee covers all services included under the plan.

Key Takeaways: Two Business Owners and the Solo 401k

Topic Key Point
Can two owners share a plan? Yes — as long as the business has no eligible non-owner, full-time W-2 employees
Holding accounts Each owner gets 3 separate accounts (pre-tax, Roth, voluntary after-tax) — 6 total for two owners
Contributions Calculated separately per owner based on their own compensation — independent of each other
Mega Backdoor Roth Both owners can each use the strategy, potentially doubling household after-tax contributions
Fees One plan, one flat annual fee at My Solo 401k Financial — even with two participants
Participant loans Each owner can borrow independently, based only on their own account balance
Multiple businesses Controlled group / affiliated service group rules may disqualify an otherwise-eligible business
Switching providers A restatement keeps the same EIN and plan name — no plan closure required

Ready to Open a Solo 401k for You and Your Business Partner?

Whether you’re opening a new Solo 401k with a spouse or business partner, or restating an existing plan from another provider, My Solo 401k Financial can help you set up the right plan structure with maximum flexibility — including the Mega Backdoor Roth strategy, participant loans, and alternative investments.

Next Steps:

Open a Solo 401k Account Today
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Visit My Solo 401k Financial

Remember: This information is provided for educational purposes only. Always consult with qualified tax, legal, and investment professionals before making investment decisions with your retirement funds.

 

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