Both the SEP IRA (Simplified Employee Pension) and the SIMPLE IRA (Savings Incentive Match Plan for Employees) were designed to give small businesses an accessible alternative to the full-complexity 401(k). They use the familiar IRA structure — individual accounts at a custodian, no plan testing, no ERISA filings — which keeps administrative overhead low.
The fundamental difference is who puts the money in. A SEP IRA is funded entirely by the employer — employees make no elective deferrals. A SIMPLE IRA allows employees to defer part of their paycheck, with the employer required to either match those deferrals or make a flat contribution for all eligible employees. That employee-contribution ability is what makes the SIMPLE attractive for businesses whose employees want to save on their own — and what makes the SEP better for self-employed owners who primarily want to maximize their own contributions.
The choice between them often comes down to two factors: whether you want employees to be able to contribute from their paychecks, and whether the SIMPLE IRA's two-year rollover restriction creates a problem for your situation.
SEP IRA: Employer-Only Contributions
In a SEP IRA, only the employer (or self-employed individual acting as the employer) makes contributions. Employees cannot make elective deferrals from their paychecks. The employer can contribute up to 25% of each eligible employee's compensation (or 25% of net self-employment income for the owner), with a 2026 cap of $72,000. Contributions are discretionary — the employer can contribute different amounts each year or skip a year entirely.
SIMPLE IRA: Employee Deferrals + Mandatory Match
A SIMPLE IRA allows employees to defer up to $17,000 (2026) from their paychecks — similar to a 401(k) but with lower limits. Catch-up contributions for age 50+ bring the standard limit to $21,000. Employers with 25 or fewer employees may use higher limits: $18,100 base ($21,950 with age-50+ catch-up), and ages 60–63 may defer an additional $5,250 under SECURE 2.0's enhanced catch-up. In exchange, the employer must either: (1) match employee deferrals dollar-for-dollar up to 3% of compensation, or (2) make a 2% non-elective contribution for all eligible employees regardless of whether they contribute. Starting in 2026, Roth SIMPLE contributions are available for employee deferrals at custodians that support it — employer contributions remain traditional (pre-tax).
The SIMPLE IRA 2-Year Rule
This is the rule that catches the most people off guard. For the first two years after you first participate in a SIMPLE IRA, you cannot roll or transfer your SIMPLE IRA balance to a traditional IRA, 401(k), or any non-SIMPLE account. You can only move it to another SIMPLE IRA. After two years, the normal rollover rules apply. This restriction also affects the early withdrawal penalty: withdrawals within the first two years face a 25% penalty (not the standard 10%).
SEP IRA Setup Flexibility
A SEP IRA can be established and funded as late as the employer's tax filing deadline, including extensions. For a sole proprietor on extension, that's October 15 of the year after the tax year. This makes the SEP IRA uniquely attractive for high earners who haven't decided on a retirement plan by year-end — you can open one in April or October and still get a prior-year deduction. No other plan offers this level of setup flexibility.
SIMPLE IRA Setup Deadline
A SIMPLE IRA must be established by October 1 of the calendar year for which it will first be used. A plan started after October 1 cannot be a new SIMPLE IRA for that year. The one exception: if you acquire a business that already had a SIMPLE IRA, you may be treated as maintaining it. This October 1 cutoff is one of the plan's major practical limitations compared to the SEP IRA.
Eligibility and Employee Coverage
SEP IRAs: employers must cover any employee who earned at least $750 (2026) in any three of the prior five years. SIMPLE IRAs: available only to employers with 100 or fewer employees who earned at least $5,000. Both plans vest employees immediately — there's no waiting period for employer contributions to belong to the employee. This full and immediate vesting is simpler than the vesting schedules used in most 401(k) plans.