What it means
Mechanically, the employer opens an IRA for each eligible person and pays contributions into it. The employee owns the account outright from day one, chooses the investments inside it, and keeps it if they leave, so there is no vesting schedule and no plan trustee to appoint.
The attraction is administrative simplicity. There is no annual plan return for most SEP arrangements, no discrimination testing of the kind a 401(k) requires, and set-up is often a single form, which is why the plan is popular with sole traders, consultants and small practices.
The central rule is that the same contribution percentage must apply to everyone eligible, including the owner. That is generous to staff and easy to explain, but it also means the owner cannot take 25% for themselves and 3% for the team, which is where larger employers usually move to a 401(k) instead.
Contribution limits are the lesser of 25% of an employee's compensation and an annual dollar cap that is updated for inflation each year, with only compensation up to a separate annual limit counted. Someone who is self-employed calculates it slightly differently, effectively around 20% of net self-employment earnings after adjusting for self-employment tax.
Flexibility is the other selling point. The percentage is chosen each year, so a business can put in 20% after a strong year and nothing at all after a weak one, which suits companies with genuinely lumpy profits.
The main watch-outs are eligibility and timing. Employees who are at least 21, have worked for the business in three of the last five years and earned above a small annual threshold generally must be included, and contributions can usually be made right up to the business tax filing deadline including extensions.
In practice
Real-world examples.
Example
A freelance graphic designer has a strong year with $90,000 of net self-employment earnings and no staff. She contributes roughly 20% of adjusted net earnings to her SEP IRA shortly before filing her tax return, reducing that year's taxable income substantially.
Example
A dental practice owner with four hygienists wants to put away 20% for himself. Once he prices the same 20% for four salaries, he switches to a 401(k) plan where employee deferrals and a smaller employer match give him a cheaper route to a similar personal contribution.
Example
A two-partner consultancy uses the SEP IRA precisely because contributions are optional each year. It contributes 18% after a year with two large projects and skips the contribution entirely in the following year when one client leaves.
Think of it
“SEP IRA is a high-contribution retirement plan for self-employed-bigger limits.
Formula
Calculation
Employer contribution for each person = chosen contribution rate x that person's eligible compensation, subject to a maximum of 25% of compensation and the annual dollar cap.
A design consultancy has three people on payroll: the owner on $200,000, a senior designer on $80,000 and a studio manager on $50,000. After a good year, the owner chooses a rate of 15% for everyone.
Owner: $200,000 x 15% = $30,000.
Senior designer: $80,000 x 15% = $12,000.
Studio manager: $50,000 x 15% = $7,500.
Total employer contribution: $30,000 + $12,000 + $7,500 = $49,500, of which $19,500 goes to staff.
If the owner instead wanted the full 25%, the totals would be $50,000, $20,000 and $12,500 respectively, or $82,500 in all. The extra $20,000 for the owner comes with an extra $13,000 for the two employees, which is exactly the trade-off that makes the same-percentage rule the deciding factor for most small businesses.Case study
Seen in the real world.
Bramble Lane Veterinary is an invented practice used for this illustrative example. The owner ran a SEP IRA for years while she was the only employee, contributing between 15% and 25% depending on how the year had gone.
When the practice grew to six staff, her accountant modelled the same 15% rate across a total eligible payroll of $310,000 and produced a cost of $46,500 a year, of which only $22,500 was the owner's own contribution. The plan that had been ideal for a single-person business had become an expensive way to fund her own retirement.
The illustrative outcome was a switch to a 401(k) with a 4% employer match, which cost the practice less overall while still letting the owner defer a large personal amount. The SEP IRA balances stayed exactly where they were, since each employee already owned their own account.
Watch out
Common mistakes.
- Believing employees can pay their own salary into a SEP IRA, when only employer contributions are permitted.
- Setting a higher contribution percentage for the owner than for the staff, which breaks the core rule of the plan.
- Overlooking part-time or seasonal staff who meet the service test and therefore must be included in the contribution.
Questions
People also ask.
What is the deadline for making a contribution?
Contributions can generally be made up to the business tax filing deadline for that year, including extensions, which is later than most people expect.
Can I have a SEP IRA and a personal IRA in the same year?
Yes, although being covered by a workplace plan may limit how much of the personal IRA contribution is tax deductible.
Is the contribution compulsory every year?
No, the percentage is chosen annually and can be set to zero in a difficult year, provided the same choice applies to everyone.
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