Retirement Plans for Small Business Owners (2026 Guide)

For most small business owners, the right retirement plan is some version of a 401(k) — almost always paired with an S-Corp structure. But the plan choice is not the first decision you make. It is the last. Before you can know which plan to open, you need to resolve entity structure, payroll, and whether you actually want to lock money in a qualified plan. The answer to those three questions points to one plan the vast majority of the time.

"The biggest mistake I see people make is not having a tax strategy before setting up a retirement plan. In the tax planning stack, retirement contributions come last. It is just the cherry on top for tax planning."

— Neal McSpadden, Founder, Tax Sherpa

Key Takeaways

• Retirement plan selection is the final step in tax planning — not the entry point. Entity structure, deduction strategies, and reasonable compensation analysis all come first.
• For Tax Sherpa clients at every revenue tier — under $250k, $250k–$750k, and $750k+ — the default answer is some form of 401(k). The only variable is whether it is solo, safe harbor, or traditional.
• The S-Corp + Solo 401(k) stack outperforms a SEP IRA for most owners because the flat-dollar employee deferral ($24,500 in 2026) adds contribution room that a percentage-of-W-2 formula like SEP cannot match.
• Three questions resolve most plan selection decisions: What entity are you now? What are your hiring plans for the next 1–3 years? Are you genuinely committed to locking money away long term, or is this primarily a tax move?
• Client attitude toward retirement matters as much as the math. A skeptic who is not committed to leaving the money alone will not benefit from the complexity of a qualified plan.
• The two universal rules Neal has observed across thousands of careers: put in substantially more than you think you need, and leave it alone. Virtually every retirement failure traces back to one of those two rules being broken.
• The S-Corp + 401(k) default has one meaningful override: states that penalize S-Corp election (Tennessee, DC) may make a Schedule C + SEP IRA more efficient, because the S-Corp structure required to generate a W-2 for Solo 401(k) contributions costs more than it saves.

Retirement Is the Last Step — Here Is Why That Changes Everything

Most retirement planning advice puts the plan front and center. Pick a SEP IRA or a Solo 401(k), fund it, done. That approach is not wrong if you have no other optimization to run. But for small business owners with legitimate complexity — entity elections, payroll, home office, business deductions, family payroll strategies — the retirement contribution should be sized only after everything else has been resolved.

The reason is mechanical. The size of a Solo 401(k) or SEP IRA employer contribution is a function of W-2 wages (for an S-Corp) or net self-employment income (for a Schedule C). Both of those numbers change dramatically as you optimize the rest of the stack. If you set your W-2 salary before running a reasonable compensation analysis, or you start a retirement plan before you know whether you are converting to an S-Corp, you may be building on a number that is about to move.

Neal's full tax planning sequence — for a typical S-Corp client — runs in this order:

1. Entity structure (S-Corp election, if not already in place)
2. Accountable plan (home office, vehicle, phone, equipment reimbursements)
3. Summit Strategy Sessions (Neal's branded consulting deduction strategy — ask about this in a consultation)
4. Family management companies and other income-shifting strategies
5. Reasonable compensation analysis (the W-2 salary that determines both payroll tax exposure and retirement contribution capacity)
6. Retirement contribution — calculated last, once the W-2 is fixed

Step 6 is where you choose a plan. Not step 1.

This does not mean retirement planning is unimportant. It means that the number you contribute, and the plan that best receives it, depend entirely on the decisions made in steps 1 through 5. Skipping to step 6 first is how business owners end up in a SEP IRA with a low-salary S-Corp — and silently cap their own contribution to a fraction of what a Solo 401(k) would allow.

The 3-Question Framework: How Neal Picks a Plan

Before running any numbers, Neal asks three questions that eliminate most of the decision tree immediately.

Question 1: What kind of entity are you now?

Entity type controls which plans are even on the table.

• S-Corp or C-Corp with payroll: Solo 401(k) is available. Employer contribution formula is 25% of W-2 wages. Employee deferral is a flat $24,500 in 2026. This combination is almost always the winning structure.
• Schedule C / sole proprietor: Solo 401(k) is still available, but the employer contribution formula shifts to approximately 20% of net self-employment income (after the half SE tax deduction). SEP IRA has the same 20% formula and fewer administrative requirements — making it competitive here, especially if the owner is in a state where S-Corp election does not make economic sense.
• Partnership or multi-member LLC taxed as a partnership: Solo 401(k) is generally not available. SEP IRA or a traditional 401(k) with employees are the primary options.

If the answer is "I'm a Schedule C and I'm thinking about converting to an S-Corp," the plan choice waits until that entity decision is made. Designing a retirement plan around a structure you are about to change is planning overhead with no payoff.

Question 2: What are your plans for the next 1–3 years?

A retirement plan that fits today but needs unwinding in 18 months when headcount changes creates expensive administrative overhead. This question surfaces that risk before it becomes a problem.

The critical threshold: Solo 401(k) eligibility ends the moment you add a full-time non-owner employee to payroll. If you are a solopreneur now but plan to hire a full-time employee within the next 12–18 months, designing a Solo 401(k) today means converting to a safe harbor or traditional 401(k) almost immediately. That is a manageable transition — but it is one worth knowing about in advance.

Conversely, if you are already past that threshold — you have employees, or you expect to have them soon — the question becomes which 401(k) design works best for your situation. Solo 401(k) is off the table; safe harbor and traditional 401(k) are in play.

Question 3: Are retirement contributions a strategic goal, or more of an afterthought?

This question sounds soft. It is not. It determines whether the complexity of a qualified plan is worth carrying.

Qualified retirement plans — 401(k)s, SEP IRAs, defined benefit plans — lock up capital. Withdrawals before age 59½ trigger income tax plus a 10% penalty (25% for SIMPLE IRA participants in their first two years). The tax deduction on the way in is real. The restriction on the way out is also real.

Some clients want to maximize contributions because they see a qualified plan as a serious wealth-building tool. They are committed to leaving the money alone for decades. For those clients, every dollar of contribution capacity matters.

Other clients are deeply skeptical of locking capital in a plan they cannot access. They prefer tax-efficient brokerage accounts, real estate equity, or other liquid assets. Neal will not push a skeptic into a plan just for the deduction. The math may favor the plan — but if the client is likely to cash out early, the penalty destroys the tax benefit.

The practical answer: "By and large, the ones who can make it work are the ones who make enough money that they can contribute enough to build up a substantial balance inside the plan, and are able to leave it alone over long periods of time."

The Default Stack: S-Corp + 401(k) at Every Revenue Tier

Once the three-question framework is run, most Tax Sherpa clients land in the same place. The specific flavor of 401(k) changes with income and headcount, but the frame holds across three revenue tiers.

This is not a product preference. It is the output of the full planning process run on every client, regardless of revenue tier. The 401(k) wins because its flat-dollar employee deferral component does not scale with W-2 wages — meaning a business owner with a deliberately low W-2 salary (a common optimization) can still contribute $24,500 from the employee side before the employer contribution percentage even begins.

One meaningful override applies across all three tiers: if you are in a state that imposes a franchise tax or other structural penalty on S-Corp election — Tennessee's excise tax and Washington DC's unincorporated business tax are the primary examples — the math may favor staying on Schedule C with a SEP IRA, because the S-Corp cost exceeds the benefit. This is a state-specific analysis, not a general rule.

Why the Solo 401(k) Beats the SEP IRA for Most S-Corp Owners

The SEP IRA is the "easy" answer — simple to open, no annual filing requirements until plan assets exceed $250,000, and flexible contribution timing (you can fund a SEP right up to the tax return extension deadline). But easy and right are not the same thing.

The fundamental problem with a SEP IRA for an S-Corp owner is that the contribution formula is percentage-only: 25% of W-2 wages, nothing more. There is no employee deferral component. An S-Corp owner who takes a $133,000 W-2 salary (a typical two-thirds/one-third distribution split on $200,000 total comp) contributes $33,250 to a SEP. The same owner in a Solo 401(k) contributes $33,250 as the employer component — and then adds $24,500 more as the employee deferral, for a total of $57,750. The gap is $24,500 per year, compounded over a career.

There is also no catch-up contribution for the SEP IRA. Business owners over 50 using a SEP are quietly leaving $8,000 per year (the 2026 age-50+ 401(k) catch-up) on the table.

The SEP remains legitimate for Schedule C owners in S-Corp-penalty states, and as a prior-year rescue tool — the SEP can be established and funded all the way to the extension deadline (October 15, 2027 for the 2026 tax year), whereas a 401(k) had to be established before December 31, 2026.

Hub Overview: What Each Page Covers

This hub covers nine total pages — this guide plus eight focused pages on specific plan types, strategies, and owner situations. Use the table below to navigate to the topic most relevant to your situation.

When the Default Does Not Apply

The S-Corp + 401(k) default holds for the vast majority of Tax Sherpa's client base. But three situations warrant a different analysis.

S-Corp penalty states. Tennessee imposes a franchise and excise tax on S-Corps that can eliminate the payroll tax savings that normally justify the election. Washington DC's unincorporated business tax creates a similar problem. In these states, a Schedule C owner with a SEP IRA may come out ahead of an S-Corp owner with a Solo 401(k), depending on net income. This is a state-by-state calculation — not an assumption.

Business owners with a deeply skeptical attitude toward qualified plans. As noted in the three-question framework, a client who is not genuinely committed to leaving money alone is not a good candidate for a qualified plan regardless of the tax math. There is no shame in this. Preferring liquid assets over tax-deferred accounts is a legitimate financial strategy. The correct response is to optimize the rest of the tax stack more aggressively, not to force a plan that will get unwound at a penalty.

High earners who have already maximized the 401(k) and want more. Once a client is contributing the full $72,000 combined limit to a Solo 401(k) — or $80,000 with the age-50+ catch-up, or $83,250 with the age 60–63 enhanced catch-up — the defined benefit and cash balance plan becomes worth analyzing. A 55-year-old with $500,000 in net self-employment income can potentially shelter over $270,000 per year by stacking a cash balance plan on top of a Solo 401(k). That level of contribution requires an actuary and a five-year commitment. See the Defined Benefit and Cash Balance Plans page for the full analysis.

The Nurse's 403(b): What Happens When You Break Rule 2

Neal has watched thousands of careers play out. The retirement failures he has seen cluster around two patterns: not contributing enough, and not leaving the money alone.

One case stands out as the stakes-setting story for this entire hub. A nurse earning $80,000 per year in her final working year had contributed a total of $120,000 to her 403(b) over the course of her career. She retired, did not adjust her lifestyle, and drew down the account steadily. Within approximately two years, the plan was empty. From that point on, her income was Social Security and family support.

This is what "leave it alone" means. The account balance at retirement is not a liquid asset. It is the engine of a multi-decade income stream. The difference between retiring with enough and retiring into a shortfall is rarely about which plan you chose. It is almost always about whether you contributed enough and whether you let compounding do its job.

"The ones who can make it work are the ones who make enough money that they can contribute enough to build up a substantial balance inside the plan, and are able to leave it alone over long periods of time." That sentence is the foundation of every retirement conversation Neal has with a new client.

How Retirement Contributions Connect to the Rest of Your Tax Strategy

A well-designed retirement contribution does more than reduce taxable income. It interacts with the rest of the tax stack in ways that multiply its value — and creates a time-limited window that many business owners miss.

Estimated taxes. Retirement contributions reduce net income, which reduces the estimated tax obligation for the current year. This is one reason timing the contribution matters: a large fourth-quarter contribution can close an estimated tax shortfall and avoid an underpayment penalty. See the Estimated Tax Hub for the full mechanics of how retirement contributions interact with quarterly payments.

Entity selection. The decision to elect S-Corp status is the prerequisite for unlocking the Solo 401(k)'s full contribution capacity. An owner on Schedule C has access to a Solo 401(k), but at a lower employer contribution rate (20% of net SE income vs. 25% of W-2 for an S-Corp), and without the payroll tax savings that help fund the contribution in the first place. The entity choice is the upstream decision. See the Entity Selection Hub for when the S-Corp election makes sense — and when it does not.

The Roth conversion window. Early business years, when aggressive deduction strategies have compressed taxable income into unusually low brackets, create a window for Roth conversions. Converting traditional IRA or pre-tax 401(k) balances to Roth during years when taxable income is low — by design, not by accident — is a tax strategy that closes as the business matures and the optimization stack is fully deployed. This is covered in detail on the FAQ page (Rollovers, RMDs, and Roth Conversions).

FAQ

Does it make sense to open a retirement plan before I have my entity structure figured out?

Almost never. The retirement plan you can use, and the contribution formula that applies, depends directly on whether you are filing as a Schedule C, an S-Corp, or a partnership. Opening a SEP IRA now and converting to a Solo 401(k) after an S-Corp election adds administrative cost with no benefit. Run the entity analysis first — that conversation is the starting point at Tax Sherpa — and let the plan choice follow from the structure you land on.

My accountant told me to open a SEP IRA. Is that wrong?

Not necessarily — but it is probably incomplete advice. The SEP IRA is the default recommendation for self-employed people because it is easy to set up and has no annual administrative filings below $250,000 in assets. If you are a Schedule C owner in a state where an S-Corp election does not make sense, the SEP IRA may genuinely be correct. But if you are already in an S-Corp, or you should be, the Solo 401(k) almost always allows a larger total contribution because of the flat-dollar employee deferral component. The question your accountant needs to answer is: what is your W-2 salary, and have you run the full tax stack before setting it?

Can my spouse participate in my Solo 401(k)?

Yes, if your spouse earns legitimate W-2 compensation from the business. A spouse who is on payroll can make their own employee deferral ($24,500 in 2026, plus catch-up if applicable) and receive their own employer contribution (25% of their W-2). This can nearly double household contribution capacity — but only if the net profit is high enough to justify legitimate compensation for both owners. Manufactured payroll creates audit risk. The Michael case study on the Solo 401(k) page illustrates what this looks like at scale: $800,000 in pre-wage taxable profit, two W-2s totaling $260,000, and approximately $150,000 in combined 2025 contributions.

What happens if I contribute too much to my retirement plan?

Excess contributions trigger a 6% excise tax per year the excess remains in the account (IRC §4973 for IRAs; §4979 for 401(k) plans). For Solo 401(k)s, excess deferrals must be corrected by April 15 of the year following the year of excess, or they are taxable in both the year contributed and the year distributed. The most common cause is contributing as both an employee and an employer without accounting for the combined limit ($72,000 in 2026, or $80,000 with the age-50+ catch-up). If you have multiple businesses or another employer's W-2 in the same year, the employee deferral limit is per person — not per plan — which compounds the risk. This is one of the questions covered in detail on the FAQ page.

Need Help With Retirement Planning?

Tax Sherpa helps solopreneurs and small business owners build a retirement strategy that works as the last step of a full tax plan — not the first.

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