Which Retirement Plan Fits Your Small Business, and What Does It Cost?
Solo 401(k), SEP, SIMPLE IRA and 401(k) options compared for New Jersey business owners
Choosing a retirement plan for your business isn't just about the highest contribution limit or the lowest fee. It's about a structure that fits the people you employ, the cash flow you can commit and what you want the business to do for you.
An owner working alone faces a different decision than an owner with a growing staff. Even two businesses with similar revenue may need different plans. So I start with two questions. Which options actually fit your business? And what does the full commitment look like, not just the advertised price?
Where should you start when choosing a retirement plan?
- Before comparing accounts, look at the business behind them.
- Are you working alone, with your spouse or with other employees?
- Who may be eligible, including part-time workers?
- Are you mainly building your own savings, offering an employee benefit or both?
- How predictable are profits and cash flow?
- Do you expect to hire?
- How much administration and flexibility do you want?
These questions narrow the field. They don't replace an eligibility review. Who has to be covered depends on the plan's rules, not on whether you call someone full-time or part-time.¹
How do the main small-business retirement plans compare?
Four options deserve a first look. A Solo 401(k) is generally a one-participant 401(k). SEP and SIMPLE plans are employer-sponsored IRA arrangements, and they work differently from each other.¹ ²
Plan | Who might consider it? | How is it funded? | Main tradeoff | What should you check? |
Solo 401(k) | An owner with no eligible employees other than a spouse | Employee deferrals and employer contributions | Saving flexibility versus administration | Eligibility, other workplace plans and hiring plans² |
SEP IRA | Owner-only businesses or employers comfortable funding eligible employees | Employer contributions | Simplicity versus employee-funding obligations | Eligible employees and contribution allocation¹ |
SIMPLE IRA | Qualifying small employers that want a relatively straightforward benefit | Employee deferrals and required employer contributions | Simpler administration versus lower saving limits and less design flexibility | Eligibility, funding formula and timing¹ |
Employer 401(k) | Businesses that want a more customizable employee retirement benefit | Employee deferrals, with employer contributions depending on design | Flexibility versus administration and cost | Traditional or safe harbor design and service needs³ |
Think of the table as a starting point. The details matter more than the label.
What should an owner-only business compare?
For an owner working alone, Solo 401(k) versus SEP IRA usually comes down to flexibility versus simplicity.
A Solo 401(k) lets you contribute in two roles, as the employee and as the employer. At some income levels, that can mean more room to save than an employer-funded SEP. The math still depends on your compensation, business structure and the applicable limits.¹ ²
A SEP generally has fewer administrative requirements. Employer contributions can change from year to year, which may suit uneven profits. The catch comes with employees. Once eligible employees are involved, contributions generally must be the same percentage of compensation for everyone covered.¹
Hypothetical: a self-employed consultant
A consultant with no employees wants to save more in strong years but expects income to swing. I'd compare the contribution calculations and the administrative work before choosing. If a hire is likely, I'd also look at what each plan would look like the day that person joins.
What changes when you have employees?
With staff, the decision becomes two questions at once: a household planning question and an employee-benefits question.
A SIMPLE IRA offers a relatively straightforward structure. Employees can contribute through payroll, and the employer must contribute under either a matching formula or a nonelective formula. A nonelective contribution goes to every eligible employee, whether or not they contribute themselves.¹
A 401(k) offers more design choices, which may include employer matching, profit sharing and other contribution features. A traditional 401(k) and a safe harbor 401(k) don't carry the same obligations. Safe harbor designs require set employer contributions in exchange for relief from certain annual testing.³
A SEP can cover employees, too. It isn't only an owner-only option, but the employer-funded commitment deserves a close look.¹
And a SIMPLE IRA isn't a SIMPLE 401(k). Similar names, different plans.¹
What does a retirement plan actually cost?
Separate the cost of running the plan from the money going into it. Both affect cash flow, but they buy very different things.
- Setup or conversion: Drafting documents, opening accounts or moving an existing plan may carry charges. Ask what implementation includes.
- Administration and recordkeeping: Maintaining participant records, processing transactions, supporting required testing and preparing filings may involve separate fees.
- Investments and advice: Investment expenses may come out of account balances. Advisory services may carry their own charge.
- Employer contributions: Matching, profit-sharing or other required contributions aren't provider fees. They're the business's funding commitment.
- Internal time: Payroll coordination, employee questions and keeping records current still take someone's time.¹ ⁴
Some costs may be paid by the business. Others may be charged to participant accounts when the plan allows it. Ask who pays each expense and what service it buys. "No setup fee" does not mean the plan has no cost.⁴
Rather than comparing advertised prices, ask for a written breakdown. Does it include employee education? What work stays with your staff? What happens to the price as headcount or assets grow?
Can tax credits offset the cost of starting a plan?
They may. Eligible employers with 50 or fewer employees can generally claim a credit for 100% of eligible startup costs, and employers with 51 to 100 employees can claim 50%. The annual credit is capped at the greater of $500 or the lesser of $250 per eligible non-highly compensated employee or $5,000, for up to three years.⁵
Two more credits may apply: $500 a year for three years for adding automatic enrollment, and a credit toward employer contributions for businesses with 50 or fewer employees.⁵
There are conditions. The plan needs at least one non-highly compensated employee, and a recent prior plan covering substantially the same employees can rule the credit out. So an owner-only business shouldn't assume it qualifies. Have your tax professional confirm eligibility before the credit goes into your cost comparison.⁵
What happens when your business grows?
A plan that fits today may need another look after a hire, a stronger year or a change in your goals.
Hiring doesn't automatically force you to close an owner-only 401(k). But employees who meet the eligibility requirements must be included, and more testing and administration may follow.²
Hypothetical: a growing company
A business with several employees wants to offer a retirement benefit while keeping its funding commitment manageable. A SIMPLE IRA may be worth considering. So may a 401(k) with a contribution formula that fits the budget. I'd compare employee eligibility, employer funding and ongoing services, not just what the owner can put away.
If the business later changes plans, timing matters. Documents, employee notices and transition rules have to be coordinated. You can't simply switch structures whenever it's convenient.¹
Where does RetireReady NJ fit?
RetireReady NJ is part of the decision, not the whole decision.
New Jersey requires employers with 10 or more employees that have been in business in the state for at least two years and don't offer a qualified retirement plan to register with RetireReady NJ and facilitate payroll deductions. Employers that already offer their own qualified plan, such as a 401(k), 403(b), SEP or SIMPLE plan, are exempt, but the exemption isn't automatic. The state requires those employers to notify RetireReady NJ of it.⁶
The registration deadlines are December 1, 2026 for employers with 20 to 24 employees and February 17, 2027 for employers with 10 to 19. Deadlines for employers with 25 or more employees have passed.⁶
For more on the state program itself, see RetireReady NJ: Your Options as a Small Business Owner. Here, the question is which plan fits your business beyond meeting a requirement.
What if you want added benefits for key executives?
Once the core plan is set, some businesses look at supplemental benefits for selected executives or key employees.
Nonqualified deferred compensation is generally a promise to pay compensation later. If the arrangement is unfunded, the executive may be exposed to the employer's creditors, and the payment timing and tax rules require careful legal review.⁷
An executive bonus arrangement using life insurance is different. In a straightforward design, the executive owns the policy, and the employer's premium payment is generally taxable compensation. Policy ownership, charges, underwriting and ongoing funding all need review.⁸
Life insurance can support an arrangement like this. It isn't a retirement plan by another name.
These belong in a separate conversation with your advisor, CPA and attorney. They're not a workaround for employee-plan requirements.
How do you choose a plan that fits?
Start with your people, your funding capacity and your own retirement goals. Then compare the administration and services each option requires.
The lowest visible fee may leave important work on your desk. A more elaborate plan may add features you don't need. The point is to understand the tradeoff before you commit.
If you'd like help sorting through the options, our advisors are happy to walk through retirement plans for business owners with you. Schedule a complimentary, no-obligation review.
Sources
1. Internal Revenue Service, Publication 560: Retirement Plans for Small Business
2. Internal Revenue Service, One-Participant 401(k) Plans
3. Internal Revenue Service, 401(k) Plan Fix-It Guide: 401(k) Plan Overview
4. U.S. Department of Labor, A Look at 401(k) Plan Fees
5. Internal Revenue Service, Retirement Plans Startup Costs Tax Credit
6. New Jersey Department of the Treasury, RetireReady NJ: Information for Employers, Program Details for Employers and About the Secure Choice Savings Program
7. Internal Revenue Service, Nonqualified Deferred Compensation Audit Techniques Guide
8. Internal Revenue Service, Publication 15-B: Employer's Tax Guide to Fringe Benefits
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