Small Business Retirement Plans: SEP vs. Solo 401(k) vs. SIMPLE IRA—2026 Contribution Limits, Employee Coverage, Setup Deadlines, and the Startup Credit (Read Before the October 1 SIMPLE Deadline)

Author: Chenchen Liu, CPA ｜ YCL Tax, Accounting & Advisory

Bottom line

If you run a restaurant, nail salon, spa, studio, or retail store in Cary / RTP / Raleigh, had a good year, and want compliant tax savings while building your own retirement, the three common plans fit different owners. A Solo 401(k) suits owners with no employees (other than a spouse): the 2026 employee deferral limit is $24,500, with a combined limit of $72,000 including employer contributions. A SEP-IRA is simple and can be set up as late as the tax return due date (including extensions), but you must contribute the same percentage for eligible employees. A SIMPLE IRA fits small shops with staff: the deferral limit is $17,000 (generally $18,100 for employers with 25 or fewer employees), and the employer must match or contribute. Timing matters: a new SIMPLE IRA must be set up by October 1, 2026 to take effect for 2026, and a Solo 401(k) should generally be adopted by December 31. Missing October 1 is not the end: for 2026 you can still set up a SEP (as late as the return due date, including extensions) or a Solo 401(k), and a SIMPLE IRA can start January 1, 2027. Eligible small employers may also claim a startup cost credit of up to $5,000 per year for three years. This article is compliance planning and education only. All amounts, rates, and thresholds are subject to current IRS/NCDOR guidance, and it does not promise an outcome.

Background

In Notice 2025-67, the IRS announced 2026 retirement plan adjustments: the 401(k) deferral limit rises from $23,500 to $24,500, the age-50 catch-up is $8,000, and the higher catch-up for ages 60–63 is $11,250. The defined contribution limit (including SEP) is $72,000, the compensation limit is $360,000, and SEP minimum compensation is $800. The SIMPLE deferral limit is $17,000 ($18,100 for applicable SIMPLE plans), with a $4,000 age-50 catch-up and $5,250 for ages 60–63; the IRA limit is $7,500. Starting in 2026, participants whose prior-year wages from the employer exceeded $150,000 must make catch-up contributions as Roth (all subject to current IRS guidance).

The SECURE 2.0 Act (signed December 2022) strengthened small-business incentives. Employers with 50 or fewer employees can claim a startup cost credit of 100% of eligible costs, capped each year at the greater of $500 or $250 × eligible non-highly compensated employees (up to $5,000), for three years; employers with 51–100 employees get 50%. There is also an employer contribution credit of up to $1,000 per employee per year and a $500 annual credit for adding auto-enrollment (three years). The startup credit requires at least one non-highly compensated participant, so an owner-only Solo 401(k) generally does not qualify (subject to current IRS guidance). North Carolina starts from federal AGI, so retirement contribution deductions generally flow through (subject to current NCDOR guidance).

What changed / options compared

Note: The comparison below contrasts 2025 and 2026 limits and key differences among the three plans. Amounts, rates, and thresholds are subject to current IRS/NCDOR guidance.

1. 401(k) / Solo 401(k) employee deferrals

- 2025: $23,500; age-50 catch-up $7,500; ages 60–63 $11,250.

- 2026: $24,500; age-50 catch-up $8,000; ages 60–63 $11,250.

2. Defined contribution limit (including SEP) and compensation limit

- 2025: $70,000; compensation limit $350,000; SEP minimum compensation $750.

- 2026: $72,000; compensation limit $360,000; SEP minimum compensation $800.

3. SIMPLE IRA

- 2025: Deferrals $16,500 (higher limit $17,600); age-50 catch-up $3,500.

- 2026: Deferrals $17,000 (higher limit $18,100); age-50 catch-up $4,000; ages 60–63 $5,250.

4. Employee coverage

- SEP: Employees age 21+, employed in 3 of the last 5 years, and earning at least $800 must be covered at the same percentage as the owner.

- SIMPLE: Employees who earned $5,000+ in any two prior years and expect $5,000 this year must be covered, with a 3% match or 2% nonelective contribution. Solo 401(k): owner (and spouse) only—eligible employees make it unavailable.

5. Setup deadlines

- SEP: Set up and fund as late as the return due date (including extensions).

- SIMPLE: A new plan generally must be effective by October 1; 401(k): generally adopted by year-end, though a sole proprietor with no employees may adopt by the filing deadline (without extensions).

6. Owner contribution base

- Sole proprietor / single-member LLC: Net self-employment earnings minus half of SE tax, so the employer portion is effectively about 20%.

- S corporation: Based on the owner’s W-2 wages, so the salary level directly affects how much can be contributed.

Self-check: are you affected?

1. One-person studio or esthetics room with no employees — A Solo 401(k) usually allows more; generally adopt it by December 31.

2. Nail salon or restaurant with several long-tenured employees — A SEP requires the same percentage for staff and may be costly; SIMPLE matching costs are more predictable.

3. You want a SIMPLE IRA for 2026 — It must be effective by October 1, 2026; if you miss it, consider a SEP, a 401(k), or a SIMPLE effective January 1, 2027.

4. You already elected S corporation status — Contributions follow W-2 wages, so plan them with S corporation reasonable compensation; deferrals must be withheld from paychecks by year-end.

5. You are 50+ and your prior-year wages exceeded $150,000 — Catch-ups must be Roth; see 2026 Roth catch-up rule.

6. You have 100 or fewer employees and no plan in the last three years — Evaluate the startup and employer contribution credits (Form 8881).

Simplified example (illustrative only)

Example A — Raleigh solo esthetics studio (sole proprietor, no employees)

Assume Ms. Zhang is 45 with 2026 Schedule C net profit of $100,000 (figures are illustrative only). Self-employment tax ≈ $100,000 × 92.35% × 15.3% ≈ $14,130, half of which is about $7,065.

- SEP: About ($100,000 − $7,065) × 20% ≈ $18,587.

- Solo 401(k): $24,500 employee deferral + about $18,587 employer contribution ≈ $43,087 (under the $72,000 limit).

Example B — Cary restaurant (S corporation, 8 eligible employees)

Assume Mr. Wang earns $60,000 in W-2 wages, staff wages total $240,000, and he sets up a SIMPLE IRA effective January 1, 2027 with a 3% match.

- Owner: Deferral up to $18,100 (the higher limit generally applies at 25 or fewer employees) + company match of $60,000 × 3% = $1,800.

- Staff match cost: If every employee defers at least 3%, at most about $240,000 × 3% = $7,200.

- Credits: The startup credit cap is the greater of $500 or 8 × $250 = $2,000, so up to $2,000 of eligible costs per year for three years; the employer contribution credit of up to $1,000 per employee is also worth evaluating.

These dollars do not calculate any real case and ignore income tax. Contribution room depends on profit, wages, employee eligibility, and plan terms; limits and rates are subject to current IRS/NCDOR guidance. This article does not promise any tax savings.

Action plan and timeline

1. Before October 1, 2026: For a SIMPLE IRA effective in 2026, sign the plan document (Form 5304-SIMPLE or 5305-SIMPLE) with a financial institution now and notify employees.

2. October–November 2026: Have a CPA project full-year profit or wages from January–September books and compare SEP, Solo 401(k), and SIMPLE contribution room and staff cost.

3. By early November: For a SIMPLE effective January 1, 2027, give employees notice of the 60-day election period.

4. By December 31, 2026: Adopt a Solo 401(k) or 401(k) (a sole proprietor with no employees may wait until the filing deadline, without extensions); S corporation owner deferrals must be withheld from wages by year-end.

5. By March 15, 2027: S corporation employer contributions can be deposited by the Form 1120-S due date (September 15 with an extension).

6. By April 15, 2027: Sole proprietors and partners can fund SEP and employer contributions by the personal return due date (October 15 with an extension); a SEP can even be set up by then.

7. At filing: Claim the startup credit on Form 8881; once plan assets pass the threshold, Form 5500-EZ may be required (subject to current IRS/NCDOR guidance). When unsure, book a YCL Free Consultation.

Related reading:

- 2026 401(k) and IRA limits

- 2026 Roth catch-up rule

- S corporation reasonable compensation

- LLC vs. S corporation election (Form 2553)

- First payroll setup for NC small businesses

How YCL can help

YCL Tax, Accounting & Advisory (Cary / RTP + Shanghai), with CPA Chenchen Liu and Gloria, supports Chinese-speaking small business owners with bilingual compliance planning—saving you time, reducing headaches, and keeping taxes compliant and efficient:

1. Retirement plan modeling — Compare SEP, Solo 401(k), and SIMPLE contribution room and staff cost using your profit or W-2 wages and employee roster, in a bilingual worksheet.

2. Deadline management — Build an action list around the October 1 SIMPLE, year-end 401(k), and SEP filing deadlines, and coordinate account setup and employee notices.

3. Payroll service — Configure deferrals, Roth catch-ups, and employer matches in payroll, file 941 / NC-5 / DES on time, and report W-2s correctly.

4. Monthly bookkeeping — Track contributions payable and deposit dates so employee deferrals are not deposited late.

5. Annual tax filing and planning — Contribution deductions on Schedule C, Form 1120-S, K-1s, and personal returns, the Form 8881 credit, and compliant strategies balancing reasonable wages and contributions (results vary by case).

6. IRS / NCDOR letters — Handle inquiries about plan contributions, Form 5500-EZ, or credits (no promise of abatement).

7. Free Consultation — Cary handles U.S. filings; our Shanghai team helps cross-border owners provide documents remotely—no promised result.

FAQ

Q: I have employees. Can I open a Solo 401(k) just for myself?

A: Generally no. A Solo 401(k) works only when the owner (and spouse) have no other eligible employees; with eligible staff, you need a plan that covers them, such as a SEP, SIMPLE, or standard 401(k).

Q: I missed the October 1 SIMPLE IRA deadline this year. What now?

A: Consider a SEP (which can be set up by the return due date, including extensions) or a 401(k), or a SIMPLE effective January 1, 2027 with a 60-day election notice to employees; an employer with a SIMPLE generally cannot maintain another plan at the same time.

Q: Are retirement contributions deductible in North Carolina too?

A: North Carolina starts from federal AGI, so qualifying retirement contribution deductions generally carry over to your NC return (subject to current NCDOR guidance).

Book a consultation

YCL Tax, Accounting & Advisory

Web: yclcpa.com ｜ Email: info@yclcpa.com

Phone: 919-802-8376 / 980-202-0666 ｜ WeChat: YCLUSA

U.S. office: 1140 Kildaire Farm Rd. STE 208, Cary, NC 27511

Shanghai office: 上海佳通路 31 弄中冶祥腾城市广场 2-516

Free Consultation: please bring a year-to-date P&L or owner W-2 wage records, an employee roster (ages, hire dates, and two years of wages), existing retirement account details, your entity type, and last year’s return (you may mask sensitive digits).

Disclaimer

This article is general information only. It is not personalized tax, legal, employment-law, or investment advice. Retirement plan contribution limits, catch-up rules, setup and funding deadlines, and small-employer credit amounts change with law and tax year—verify current IRS and NCDOR pages and any official notice you receive. For advice about your situation, consult a licensed professional.