SEP IRA vs SIMPLE IRA vs Solo 401(k): choosing a plan for your Idaho business
A plain-English comparison of three common retirement plans for business owners, including who each plan fits, how contributions work, and what changes when you hire.
Choosing between a simplified employee pension (SEP) IRA, a Savings Incentive Match Plan for Employees (SIMPLE) IRA, and a Solo 401(k) depends on who works in your business, who contributes, and how much flexibility you want. Employers fund a SEP. A SIMPLE IRA lets employees save from pay, with an employer contribution. A Solo 401(k) suits owners without employees.
A few quick definitions. An IRA is an individual retirement account. A 401(k) is an employer plan that lets workers save part of their pay before it is taxed, or as Roth savings if the plan allows it. A Solo 401(k) is a 401(k) designed for a business owner with no employees other than a spouse.
All three plans can help you save for retirement while lowering taxable income today. They differ in setup, ongoing work, and how they treat employees. Here is how to think through the choice.
What is a SEP IRA?
A simplified employee pension lets your business make contributions to IRAs for you and for eligible employees. The employer makes all contributions. Employees do not make salary deferrals into a SEP.
The appeal is simplicity. A SEP has light paperwork and no annual plan return for the plan itself. You can also change the contribution from year to year, or skip a year when cash is tight.
The tradeoff is fairness rules. When you contribute for yourself, you generally must contribute the same share of pay for every eligible employee. For a business with no staff, that is not an issue. For a business with a growing team, it can make a SEP an expensive way to fund the owner's retirement.
What is a SIMPLE IRA?
A SIMPLE IRA is built for smaller employers. The IRS sets a limit on how many employees a business can have and still offer one. Employees choose to defer part of their pay, and the employer must make a contribution each year, either a matching contribution or a set contribution for every eligible employee.
A SIMPLE IRA is often a middle ground. It gives employees a way to save on their own, with less administration than a traditional 401(k). It does not require the annual nondiscrimination testing that many 401(k) plans face.
There are limits to keep in mind. Employee deferral limits are generally lower than in a 401(k). The required employer contribution is not optional once the plan is in place. And a business that sponsors a SIMPLE IRA generally cannot maintain another retirement plan at the same time.
What is a Solo 401(k)?
A Solo 401(k), sometimes called an individual 401(k), is a 401(k) for a business with no employees besides the owner. A spouse who works in the business can usually participate too.
Its main strength is that you contribute in two roles. As the employee, you can make salary deferrals. As the employer, you can add a profit sharing contribution. Combined, this often allows higher total savings at a given income than a SEP, especially at moderate income levels.
A Solo 401(k) may also offer a Roth option and plan loans, depending on the provider. The added work is modest, though the plan may need an annual IRS filing once its assets grow past a set level.
How do the three plans compare?
- Who contributes: a SEP is employer funded; a SIMPLE IRA uses employee deferrals plus a required employer contribution; a Solo 401(k) allows both employee deferrals and employer contributions for the owner.
- Who it fits: a SEP fits owners with no staff or very few staff who want flexibility; a SIMPLE IRA fits smaller teams that want a low-maintenance employee benefit; a Solo 401(k) fits businesses with no employees besides the owner.
- Contribution room: SIMPLE IRA limits are generally lower; SEP and Solo 401(k) limits are generally higher, and a Solo 401(k) often reaches its limit at a lower income.
- Flexibility: SEP contributions can vary each year; SIMPLE employer contributions are required; Solo 401(k) contributions can vary within plan rules.
- Administration: SEP and SIMPLE IRAs are light; a Solo 401(k) is light to moderate.
Contribution limits change each year. For current figures, see the IRS retirement plans page or ask your CPA team.
Which plan fits your business?
Start with a few questions:
- Do you have employees now, or do you expect to hire soon?
- Do you want employees to be able to save from their own pay?
- How steady is your cash flow, and could you commit to a required employer contribution?
- How much do you want to save for yourself compared with what you can fund for a team?
- Do you value features such as Roth savings or plan loans?
An owner with no employees and strong, steady income often looks closely at a Solo 401(k). An owner with uneven income and no staff may prefer the flexibility of a SEP. An owner with a small team that wants a simple employee benefit may lean toward a SIMPLE IRA.
What changes when you hire?
Your plan should grow with your business. A Solo 401(k) no longer fits once you have eligible employees. A SEP can become costly because of the same-share rule. A SIMPLE IRA may work for a while, but a growing team may outgrow its employee limit or want higher savings room.
At that point, many owners look at a traditional or safe harbor 401(k), sometimes paired with profit sharing. Our page on corporate retirement plans explains how those plans are structured and how they can serve both owners and employees.
How the plan fits your bigger picture
A retirement plan is a tool, not a full strategy. The right choice depends on your entity type, how you pay yourself, your tax picture, and how the business fits into your long-term goals. Those pieces connect, which is why the plan decision works well as part of broader wealth management for business owners.
Your CPA team can model the tax effect of each option. A plan provider or administrator sets up and runs the plan. An advisor can help you weigh the options against your goals and coordinate the investment side. At Cooper Norman Wealth, we coordinate and advise; your CPA team and plan provider handle the tax filings and plan administration.
If you would like to talk through your options, you can schedule a conversation with our team.
This article is for general educational purposes only and is not individualized investment, tax, or legal advice. Rules and limits change; consult your CPA, attorney, and advisor about your situation. Cooper Norman and Cooper Norman Wealth are separate and distinct companies, providing separate and distinct services.