SEP, 401(k), or Cash Balance?

A 10-Minute Feasibility Test for Contractors

The "cheapest" retirement plan isn't cheapest if it blocks the owner contribution you wanted, or forces a staff contribution cost you didn't see coming. Picking a plan based on setup fees alone is one of the most common and expensive mistakes contracting business owners make.

Here's a quick way to screen the three most common options before you or your CPA spend real time modeling one.

Snapshot of Each Option and When It Fits

SEP IRA. The simplest structure to set up and run. No annual filing, minimal admin cost. The catch for a crew-based business: if you contribute for yourself, you generally have to contribute the same percentage of pay to every eligible employee. For 2026, the contribution limit is 25% of compensation, up to $72,000. A SEP fits best for a very small crew, a business with few or no eligible employees, or an owner who wants simplicity more than maximum contribution flexibility.

401(k) (Solo or company-sponsored). More setup and ongoing administration than a SEP, but far more flexibility. For 2026, employees can defer up to $24,500 of their own pay, plus employer contributions on top, for a combined limit that lets an owner put away significantly more than a SEP allows at the same income level. A Solo 401(k) works well for an owner with no employees (or only a spouse). A full company 401(k) works for a growing crew, especially if you want features like a match formula, loans, or a Roth option. Please be aware, nondiscrimination testing means highly compensated owners can be limited unless the plan is designed carefully.

Profit sharing as an add-on. Profit sharing is a discretionary employer contribution that sits on top of employee deferrals in a 401(k). These contributions are separate from a match, and not tied to what employees choose to defer. It's the piece that lets an owner move from the $24,500 deferral limit up toward the combined $72,000 annual cap for 2026 (the Section 415(c) limit, covering deferrals plus all employer contributions). A flat, same-percentage-for-everyone profit sharing formula behaves a lot like a SEP. It’s simple, but it can get expensive fast with a larger crew. Where profit sharing earns its complexity is a formula like new comparability (cross-testing), which can legally weight contributions more heavily toward older, higher-paid owners while still passing nondiscrimination testing. This feature often comes at a lower required staff cost than a flat formula or a SEP would produce for the same owner contribution. Whether this is worth the added plan design cost depends on your crew's age and pay mix, which is exactly the kind of thing worth modeling rather than assuming.

Cash balance plan. A defined-benefit style plan layered on top of a 401(k), aimed at business owners who are behind on retirement savings and want to put away far more than 401(k) or SEP limits allow. Depending on your age and income, this could be $100,000-plus per year. It requires actuarial design, ongoing administration, and a real commitment to funding it consistently. It fits a profitable, stable business with an owner in their 40s or older who wants to catch up fast, and it usually only pencils out well alongside a 401(k), not as a replacement for one.

If you want the full guide, check out my Contractor Tax Playbook.

The 3-Question Feasibility Screen

Before modeling anything in detail, three questions will point you toward the right family of plan:

1. How many W-2 employees do you have, and what do they earn? A larger crew at meaningful wages changes the math fast. Every plan that gives you flexibility for yourself also has rules about what you owe your staff. A one- or two-person operation has far more options open than a business with fifteen field employees.

2. How much do you actually want to contribute for yourself this year? If the number you want to save is well within SEP or standard 401(k) limits, you likely don't need the complexity of a cash balance plan. However, if you're trying to shelter a large amount of income in a strong year, a SEP or standard 401(k) alone may cap you out well below what you want.

3. How stable and predictable is this year's profit, and next year's? SEP contributions can flex year to year with profitability; easily skip a lean year without penalty. A 401(k) with a match has more moving parts but still allows some flexibility. A cash balance plan generally requires consistent, near-mandatory funding for several years to avoid IRS penalties for underfunding. This makes it a poor fit for a business with lumpy or uncertain profit.

Answer those three honestly and you'll usually already know which family of plan is worth spending real time on.

Fee Comparison

Setup and administration cost is a real input to feasibility, but treating it as the deciding factor is how owners end up in a plan that's cheap to run but expensive in what it can't do for them.

SEP IRA. The cheapest to operate by a wide margin. No plan document filing, no annual Form 5500, no third-party administrator. Cost is typically limited to whatever the brokerage or custodian charges on the account itself and is often little to nothing beyond fund expense ratios. This is the main reason SEPs get recommended by default, even if they're not actually the best fit for the business.

401(k) (Solo or company-sponsored). More moving parts, more cost. A Solo 401(k) for an owner with no employees can still be relatively inexpensive; there will be a modest setup fee and a low annual cost through a discount provider. A full company 401(k) with employees typically runs a setup fee, an annual third-party administrator (TPA) fee, per-participant recordkeeping charges, and required annual Form 5500 filing. Adding profit sharing — especially a new comparability formula — usually adds an annual actuarial or compliance testing fee on top of standard TPA costs, since someone has to certify the allocation passes nondiscrimination testing each year.

Cash balance plan. The most expensive to set up and maintain of the three, and that's expected, not a red flag — it requires an actuary to design the plan, certify funding levels, and recertify annually, on top of the 401(k) administration it typically sits alongside. Setup and annual actuarial fees are a significant, ongoing cost of the plan, not a one-time expense.

The number that actually matters: compare the added administrative cost of a 401(k) or cash balance plan against the extra contribution room (and the owner/staff allocation advantage covered below) it unlocks versus a SEP. A few thousand dollars a year in administration is a rounding error next to tens of thousands in additional owner contribution capacity — but it's a real cost against a SEP-sized contribution goal that a more complex plan wouldn't increase. Fee comparison only means something next to what each plan lets you contribute and keep.

A note on scope: the costs above cover plan administration and actuarial work only — they don't include fees for advisory, plan design, or ongoing management services, which vary by provider and by the scope of work involved. Ask about those directly as part of comparing your options.

Owner vs. Staff Cost Trade-Offs

The number that matters isn't the plan's contribution limit — it's what you keep after covering required staff contributions.

Example, generalized: an owner wants to contribute close to the maximum for themselves and has five field employees earning a combined $250,000 in wages. Under a SEP, contributing 20% of their own pay means contributing that same 20% for every eligible employee. A required staff cost can run into tens of thousands of dollars before the owner sees any benefit. Under a properly designed 401(k) with profit-sharing that uses permitted allocation formulas (like new comparability), the same business might be able to weight contributions more heavily toward the owner while satisfying nondiscrimination rules with a smaller required staff contribution.

That gap — required staff cost under a SEP versus a well-designed 401(k) — is often the single biggest factor in which plan saves the owner more money net of what goes to the crew. It's also exactly the kind of number a "cheapest to set up" comparison misses entirely.

Timeline: When to Decide to Hit This Year's Deadlines

Plan deadlines vary by type, and missing one can push a year's contribution — and its tax benefit — out entirely:

• SEP IRA: can be established and funded up until the business's tax filing deadline, including extensions — the most forgiving timeline of the three, which is part of why it's popular for last-minute planning.

• Solo or company 401(k): the plan itself generally needs to be established by the end of the calendar year (some employer contributions can still be made up until the filing deadline, but employee deferral elections need to be in place before the pay they apply to).

• Cash balance plan: needs the most lead time due to actuarial design, documentation, and plan establishment. These administrative items typically need to happen well before year-end to be funded for the current year, and contributions are often due by the filing deadline including extensions.

If a cash balance plan is even a possibility for this year, that's the one to start conversations about earliest — everything else has more room to decide later in the year.

Next Steps if the Quick Test Says "Green Light"

If the screen above points toward a plan that looks like a real fit in terms of affordability, and actually structured to get meaningful money to the owner without an outsized staff cost, the next step is running real numbers: actual payroll data, actual ages, and an actual contribution target, modeled by whoever will administer the plan.

That's a different conversation than picking a plan off a comparison chart, and it's worth having before a deadline forces a rushed decision.

Schedule a 30-minute Plan Fit Call and we'll walk through your crew, your numbers, and which plan actually clears the bar for your business.

This post is for general informational purposes and isn't tax, legal, or investment advice for your specific situation. Figures referenced reflect 2026 IRS contribution limits and are subject to change; plan design should be confirmed with a retirement plan administrator or advisor.