SEP IRA: The Simple, High-Limit Plan for Solo and Small Business Owners

The SEP IRA (Simplified Employee Pension) is the easiest retirement plan in the Internal Revenue Code. The IRS designed it to give small business owners a high-limit retirement vehicle without the administrative burden of a full 401(k) plan. No annual filing. No complex testing. No plan documents beyond a simple form. You set it up once, contribute each year, and that's it.

For solo business owners and owner-operators with no other employees, the SEP IRA is a strong default. For business owners with W-2 employees, the SEP becomes more complicated — and often less attractive than a 401(k) — because of the coverage rules that require you to contribute for employees at the same percentage rate as yourself.

This guide covers how SEP IRAs work, how the contribution math runs, the employee coverage rules that catch owners by surprise, and how to decide between a SEP IRA and alternatives (primarily Solo 401(k) and SIMPLE IRA).

A SEP IRA is, mechanically, just a collection of traditional IRAs — one for each eligible employee (including the owner). The employer makes contributions to each eligible employee's SEP IRA. Employees don't make contributions directly. There's no employee elective deferral option. It's an employer-only contribution plan.

The business's contribution goes into each eligible employee's SEP IRA, where it's owned by that employee immediately (fully vested — no vesting schedule allowed). The employee can invest the funds in whatever the IRA custodian allows.

Key features:

• Easy setup — a single IRS Form 5305-SEP establishes the plan
• No annual IRS filing required (no Form 5500)
• No nondiscrimination testing
• Contributions are discretionary year-to-year (you can skip a year)
• Contributions are immediately 100% vested to the employee
• Investments are managed at the IRA level by each employee
• Traditional (pre-tax) contributions only — no Roth SEP under current law (though SECURE 2.0 changes may allow Roth SEPs going forward via the plan provisions)

The SEP IRA contribution limit is the lesser of:

• 25% of compensation (for corporate employees) / approximately 20% of net self-employment earnings (for sole proprietors/partners), or
• The annual dollar limit ($69,000 for 2024, $70,000 for 2025)

The "25% vs. 20%" distinction matters and mirrors the same math we saw for the Solo 401(k) employer contribution:

For corporate owners (S corp, C corp): Compensation is W-2 wages. The limit is 25% of W-2 compensation.

For sole proprietors and partners: "Compensation" is net self-employment earnings (Schedule C profit or partnership K-1 earnings from self-employment), adjusted for the deductible half of SE tax. The effective limit is 20% of this figure — the math works out because the 25% rate applies to compensation calculated after subtracting the SEP contribution itself, which is a recursive formula that resolves to 20%.

A worked example for a sole proprietor with $150,000 Schedule C net profit: - Deductible half of SE tax: approximately $7,575 - Net earnings: approximately $142,425 - Maximum SEP contribution (20%): approximately $28,485

A worked example for an S corp owner with $80,000 W-2: - Maximum SEP contribution (25%): $20,000

The annual dollar cap ($69K/$70K) is rarely reached by smaller businesses but starts mattering once W-2 compensation exceeds roughly $276,000 (S corp) or net SE earnings exceed roughly $345,000 (sole prop).

Note that the compensation considered for the percentage calculation is capped at the annual compensation limit ($345,000 for 2024, $350,000 for 2025) — high earners can't scale the 25% against unlimited wages.

Here's where SEP IRAs get complicated for business owners with employees. The SEP IRA must cover all employees who meet these criteria (unless the employer elects more lenient rules, which most do):

• Age 21 or older
• Have worked for the employer in at least 3 of the immediately preceding 5 years
• Received at least $750 in compensation from the employer during the year (for 2024; indexed)

If an employee meets these criteria, they must be included in the SEP, and the employer must contribute to their SEP IRA at the same percentage rate as the owner's contribution. This is the critical constraint.

The "same percentage" rule is strict. If the owner wants to contribute 20% of compensation for themselves, every eligible employee must also receive 20% of their compensation. There's no discretion. There's no tiering. There's no way to contribute more for owners than for employees.

For solo operators or owner-only businesses (including owner plus spouse), this rule is irrelevant — you're the only eligible employee. For owners with 5 employees each earning $50,000, a 20% owner contribution means the business contributes $10,000 × 5 = $50,000 for employees, on top of the owner's contribution.

This is why SEP IRAs work well for solo operators and become less attractive as the employee headcount grows. When you have employees, the same-percentage rule either (a) forces large employee contributions that the business can't afford, or (b) caps the owner's contribution at a lower percentage than would otherwise be available.

For business owners with employees, a 401(k) plan often becomes preferable because it allows employees to contribute their own money (employee elective deferrals) and lets the employer make discretionary matching or profit-sharing contributions at rates that can differ from the owner's effective contribution rate.

The "3 out of 5 years" service requirement creates an odd interaction with part-time employees. A long-tenured part-time employee who worked even a few hours in 3 separate years may need to be covered. An employer can't exclude part-time employees by simply designating them as such.

The employer can elect more restrictive eligibility terms in the plan document (for example, requiring only one year of service instead of three, which is a less restrictive rule from the employee's perspective), but can't go more lenient than the statutory maximum.

For businesses with seasonal workers, long-tenured part-timers, or a fluctuating workforce, the SEP IRA's coverage rules may be harder to manage than they first appear.

Setting up a SEP IRA is genuinely simple:

1. Complete IRS Form 5305-SEP (one-page form). Keep it with your business records; no IRS filing required.
2. Provide information about the SEP to all eligible employees.
3. Open a SEP IRA account with a qualified custodian (Fidelity, Schwab, Vanguard, etc.) for each eligible employee.
4. Make contributions to each eligible employee's SEP IRA account.

Setup typically takes a day or two. The cost is whatever the IRA custodian charges, which for most discount brokers is zero.

Deadline: The SEP can be established and funded as late as the tax return filing deadline (including extensions) for the year you want contributions to count against. This is unusually flexible — unlike most retirement plans, the SEP IRA doesn't require you to establish it during the tax year. A sole proprietor who realizes in September that they want to make a retroactive SEP contribution for the prior year can still do so (as long as they haven't filed their taxes yet, or can extend).

One of the underappreciated features of the SEP IRA is contribution flexibility. Each year, you decide whether and how much to contribute. You can contribute 20% one year and 5% the next, or skip a year entirely.

The same-percentage rule applies within a contribution year but doesn't force consistency across years. This is useful for businesses with variable profitability — you can make large contributions in strong years and skip in weak years without penalty.

Compare this to a 401(k) with employer matching contributions, which typically creates an implied or explicit expectation of consistent contributions. SEP IRA discretion is genuinely discretionary.

The trade-off: the discretion applies to employees too. Employees know their contribution percentage is at the owner's discretion each year. For employee morale and retention, many employers effectively commit to a target contribution rate even though it's legally discretionary.

SEP IRA balances are held in traditional IRA accounts (technically, a SEP IRA is just a traditional IRA that accepts employer contributions). This means the balances participate in the broader IRA rollover and Roth conversion ecosystem.

You can: - Roll SEP IRA balances to a traditional IRA at any time - Convert SEP IRA balances to a Roth IRA (a taxable event, but a planning tool) - Combine SEP IRA balances with other traditional IRAs for investment management purposes - Use SEP IRA balances for Qualified Charitable Distributions at age 70½+

One caveat: having significant SEP IRA (or other traditional IRA) balances can complicate the "backdoor Roth IRA" strategy. Under the pro-rata rule, Roth conversions from a traditional IRA are taxed pro-rata based on all your traditional IRA balances — including SEP IRA balances. If you're pursuing backdoor Roth contributions, having large SEP IRA balances can make those conversions partially taxable in a way that undermines the strategy.

The workaround is sometimes to roll SEP IRA balances into a 401(k) (if available) to remove them from the pro-rata calculation. Solo 401(k) plans often allow this rollover-in, making the combination of a Solo 401(k) and a backdoor Roth IRA more tax-efficient than SEP IRA + backdoor Roth.

For solo owners without employees, the SEP IRA vs. Solo 401(k) decision involves these trade-offs:

Contribution capacity at lower income levels: Solo 401(k) wins. The Solo 401(k) employee elective deferral ($23,000+) is available regardless of business profit, while the SEP contribution is capped at a percentage of compensation. At modest income levels, this difference matters significantly.

Contribution capacity at higher income levels: They converge at the 415(c) limit.

Catch-up contributions (age 50+): Solo 401(k) only. The SEP has no catch-up mechanism.

Roth option: Solo 401(k) offers Roth elective deferrals. SEP IRAs have traditionally been pre-tax only, though SECURE 2.0 provides for Roth SEP contributions (implementation details vary).

Loan provisions: Solo 401(k) only.

Setup simplicity: SEP IRA wins clearly. No plan document beyond Form 5305-SEP. No annual filing.

Ongoing compliance: SEP IRA wins. Solo 401(k) eventually requires Form 5500-EZ once assets exceed $250,000.

Backdoor Roth compatibility: Solo 401(k) is cleaner because 401(k) balances don't enter the pro-rata rule for IRA conversions.

Establishment deadline flexibility: SEP IRA wins for retroactive planning. A SEP can be established up to the tax filing deadline for the year being covered.

For most solo owners focused on retirement maximization, Solo 401(k) is the better choice. For solo owners focused on simplicity, especially those who haven't yet established a plan and want to retroactively capture contributions for the prior year, SEP IRA is appealing.

For businesses with W-2 employees, neither SEP IRA nor Solo 401(k) is well-suited. The practical alternatives are:

• SIMPLE IRA (covered in 3.5): Allows employee elective deferrals; lower contribution limits; employer must contribute a minimum match or non-elective contribution.
• Safe harbor 401(k): Traditional 401(k) with mandatory employer contributions that satisfy nondiscrimination testing; higher contribution limits; more complex administration.
• Traditional 401(k): Allows employee deferrals and discretionary employer contributions; requires nondiscrimination testing that can limit owner contributions if rank-and-file employees don't participate.

The SEP IRA's strict same-percentage rule generally makes it worse than these alternatives once you have multiple employees. Evaluate the SEP IRA seriously only for solo operations or very small teams (1-2 employees where proportional contributions remain economically manageable).

The SEP IRA is the right choice when:

• You're a solo operator without employees
• You want simplicity over maximum contribution capacity
• You have variable income and want maximum contribution flexibility year-to-year
• You're doing retroactive retirement planning after the tax year has ended
• You have a spouse-only business and want straightforward administration

It's less likely to be the right choice when:

• You want to maximize contributions at lower income levels (Solo 401(k) wins)
• You want catch-up contributions (Solo 401(k) only)
• You want loan flexibility (Solo 401(k) only)
• You want Roth contributions at high income levels
• You have non-spouse W-2 employees (other plans are usually better)
• You're planning backdoor Roth contributions (large SEP balances complicate this)

The SEP IRA's position in the retirement plan ecosystem is as the simplest high-limit option. For owners who match its use case — solo, simplicity-preferring, flexibility-preferring — it's an excellent tool. For owners who don't match, the alternatives are generally better worth the added complexity.