Can a Business Owner Have a 401(k)? Plans, Limits, and Setup

Yes, a business owner can have a 401(k), whether you operate as a sole proprietor, an LLC, a partnership, or a corporation. Which version you set up depends almost entirely on one question: does the business have employees beyond you and your spouse? If not, a solo 401(k) gives you the same tax advantages as any large-company plan with far less paperwork. If you have staff, you’ll run either a traditional or a safe harbor 401(k) and take on real compliance duties. For 2026, combined employee-plus-employer contributions can reach $72,000, which makes this one of the strongest tax-advantaged tools available to entrepreneurs.

Solo 401(k) When It’s Just You

If your business has no common-law employees other than yourself and possibly your spouse, you qualify for what the IRS calls a “one-participant 401(k) plan.”¹ It works like any standard 401(k) but skips the nondiscrimination testing larger plans require, because there are no rank-and-file employees whose benefits need to be compared against yours.²

A spouse who earns income from the business can participate too, effectively doubling household contribution capacity under a single plan.

How you calculate the compensation your contributions are based on depends on the entity. Sole proprietors and single-member LLCs use net self-employment earnings, reduced by half the self-employment tax and by the plan contribution itself. That circular calculation is trickier than it looks, and the IRS publishes rate tables in Publication 560 to help.³ For an S corporation or C corporation owner, the base is simply the W-2 salary the corporation pays you.¹

Solo status lasts only until you hire. Once someone works more than 1,000 hours in a 12-month period, that person becomes eligible to participate, and the plan must comply with the full range of nondiscrimination testing and reporting that applies to any multi-participant 401(k).⁴ Many growing businesses get tripped up here.

Plans When You Have Employees

With staff on payroll, the practical choice is between a traditional 401(k) and a safe harbor 401(k). The decision comes down to how much testing risk you accept versus how much you’re willing to contribute for employees.

Traditional 401(k)

A traditional plan requires annual ADP and ACP nondiscrimination tests to ensure highly compensated employees (including the owner) aren’t deferring or receiving matches at rates that dwarf everyone else. If the plan fails, you have to correct it, usually by returning excess contributions to the highly compensated group. Miss the two-and-a-half-month correction window after the plan year ends and the employer owes a 10% excise tax on the excess; miss the full 12-month window and the plan can lose its qualified status.⁵

In exchange, a traditional plan lets you use vesting schedules on employer contributions. A six-year graded schedule starts at 20% after two years and reaches 100% at six; a three-year cliff vests nothing until year three, then everything at once.⁶ In businesses with turnover, unvested amounts revert to the plan as forfeitures when employees leave.

Safe Harbor 401(k)

A safe harbor plan skips the ADP/ACP testing entirely, in exchange for guaranteed employer contributions. You pick one of two structures:

A non-elective contribution of at least 3% of compensation for every eligible employee, whether or not they defer any of their own pay.⁷
A matching contribution: the basic safe harbor match is 100% on the first 3% deferred, plus 50% on the next 2%. Enhanced formulas, such as 100% on the first 4%, also qualify if they’re at least as generous at every deferral level.

The catch: safe harbor employer contributions vest immediately at 100%. No graded or cliff schedule is allowed.⁶ For owners who want to max out their own contributions without worrying about test failures, safe harbor is usually worth the cost.

2026 Contribution Limits

As a business owner you wear two hats in your own 401(k): employee and employer. The dual role is what lets you contribute far more than a typical worker at someone else’s company.

Employee Side

The 2026 elective deferral limit is $24,500. At age 50 or older, you can add a standard catch-up of $8,000, for a total of $32,500.⁸

SECURE 2.0 created a higher “super catch-up” for participants who are 60, 61, 62, or 63 during the plan year. For 2026, that catch-up is $11,250 instead of $8,000, bringing the maximum deferral for those ages to $35,750.⁸

Employer Side

The business can add profit-sharing or matching contributions of up to 25% of compensation. The combined ceiling from both sides is $72,000 for 2026, before catch-ups.⁹ Add the standard catch-up and the ceiling reaches $80,000; add the super catch-up for ages 60 through 63 and it hits $83,250.

Compensation itself is capped at $360,000 for 2026, so paying yourself above that doesn’t buy you additional room in the contribution formula.⁹

If You Contribute Too Much

Excess elective deferrals not corrected by April 15 of the following year get taxed twice: once in the year of the contribution and again when you eventually withdraw the money.¹⁰ If you’re under 59½ when you take it out, the distribution can also trigger the 10% early withdrawal penalty.

The Roth Option

Most solo 401(k) providers, and most employer 401(k) platforms, now offer a designated Roth account alongside the traditional pre-tax bucket. With Roth deferrals you pay income tax on the contribution upfront and take qualified distributions tax-free in retirement. You can split elective deferrals between traditional and Roth in any proportion, so long as the combined total stays inside the annual deferral limit.¹¹

Roth 401(k)s have no income limit, unlike Roth IRAs, which is why they’re the main route for high-earning owners who want tax-free income later. Employer profit-sharing contributions still go into a pre-tax account by default, though plans may now allow Roth matching and nonelective contributions under SECURE 2.0. Those amounts are reported on Form 1099-R for the year they land in your account.¹²

Tax Credits for Starting a Plan

SECURE 2.0 made launching a small-business 401(k) substantially cheaper. The credits below apply for the first three years the plan is in effect.

Startup cost credit. Businesses with 50 or fewer employees who earned at least $5,000 in the prior year can claim 100% of eligible administrative and setup costs, up to the greater of $500 or $250 multiplied by the number of non-highly-compensated eligible participants, capped at $5,000 per year. Businesses with 51 to 100 employees get the credit at 50%.¹³
Employer contribution credit. Businesses with 50 or fewer employees can also claim a credit for contributions made on behalf of employees earning $100,000 or less: 100% of contributions (up to $1,000 per participant) in the first two years, phasing down to 25% by year five.¹³
Auto-enrollment credit. Adding an automatic enrollment feature earns an additional $500 per year for three years.¹³

For a solo operation or a business with a handful of employees, these credits can wipe out the setup and running cost of the plan in its early years.

Automatic Enrollment for New Plans

SECURE 2.0 requires automatic enrollment for most 401(k) plans established after December 29, 2022, effective for plan years beginning on or after January 1, 2025. Eligible employees must be enrolled at a default contribution rate between 3% and 10%, escalating 1% each year until reaching a maximum between 10% and 15%. Employees can opt out or change their rate at any time.

Several exemptions apply. Businesses with fewer than 11 employees are exempt, as are businesses that have existed for fewer than three years. Plans in existence before December 29, 2022, are grandfathered. Church and governmental plans are also exempt. If you’re launching a new plan in 2026 with 11 or more employees, build auto-enrollment into the plan design from the start.

Setup Steps and Deadlines

Getting the plan running involves selecting a financial institution or third-party administrator, then adopting a written plan document that spells out eligibility, contribution formulas, vesting, and day-to-day operation. Most providers offer pre-approved documents you customize through an adoption agreement, choosing options like minimum participation age and whether to include a Roth feature.¹⁴

The deadlines are where owners lose money. For S corporations, partnerships, and multi-member LLCs, the plan must be formally adopted by December 31 of the year you want to make employee elective deferrals. Sole proprietors and single-member LLCs have more room and can establish the plan after year-end while still making employee deferrals for the prior year. Employer profit-sharing contributions have a separate, later deadline, generally the business’s tax return due date including extensions.

SECURE also opened a retroactive door. A business can adopt a new plan up to its tax filing deadline (including extensions) and treat it as effective for the prior tax year, at least for employer contributions. Owners who had a strong year but didn’t plan ahead can still capture the deduction.

Ongoing Duties If You Have Employees

Setup is the easy part. Running the plan creates real legal obligations. As sponsor, you’re a fiduciary under ERISA, and that means acting solely in the interests of plan participants, exercising prudence in selecting and monitoring investments, keeping expenses reasonable, diversifying investment options, and following the plan document as written.¹⁵ You can’t pick an expensive fund because you know the manager, and you can’t set the plan up and walk away.

Prohibited transactions are a separate hazard. You cannot sell property to the plan, borrow from it on favorable terms, or use plan assets for your own benefit. A prohibited transaction triggers an excise tax on the disqualified person involved, and that group includes you, your family members, the business, and service providers.¹⁶

Plans covering employees also need an ERISA fidelity bond for every person who handles plan funds. The bond must cover at least 10% of the plan assets handled in the prior year, with a minimum of $1,000 and a maximum requirement of $500,000 ($1,000,000 if the plan holds employer securities).¹⁷ Employee deferrals withheld from paychecks must be deposited into the plan trust promptly; for plans with fewer than 100 participants, the safe harbor is seven business days after payday.¹⁵

Annual Filings

Solo 401(k) plans with combined assets over $250,000 at year-end must file Form 5500-EZ with the IRS.¹⁸ Below that threshold, no annual filing is required unless it’s the plan’s final year. If you run more than one one-participant plan, the $250,000 test looks at combined assets.¹⁹

Plans with employees file the standard Form 5500, a more detailed return typically prepared by the third-party administrator. Missing the deadline can bring penalties from both the IRS and Department of Labor, and late filers tend to draw audit attention. The IRS also publishes remedial amendment deadlines when tax law changes, and missing one can jeopardize the plan’s qualified status.

Getting Money Out Before Retirement

A 401(k) isn’t sealed until age 59½. If your plan document allows loans, you can borrow up to the lesser of $50,000 or 50% of your vested balance, with quarterly payments and a five-year repayment window. Loans used to buy a primary residence can extend beyond five years.²⁰ The interest goes back to your own account, but the borrowed money isn’t invested while it’s out.

Withdrawals before 59½ generally trigger a 10% additional tax on top of income tax.²¹ The exception most relevant to business owners: if you separate from service during or after the year you turn 55, the 10% penalty doesn’t apply. Other exceptions cover disability, substantially equal periodic payments based on life expectancy, distributions up to $22,000 for qualified individuals affected by federally declared disasters, and SECURE 2.0’s penalty-free emergency withdrawal of up to $1,000 per year.

If you plan to wind down the business in your mid-50s, the age-55 rule makes your 401(k) a realistic bridge to full retirement age.

1
Internal Revenue Service. One-Participant 401(k) Plans
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Internal Revenue Service. Retirement Plans for Self-Employed People
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Internal Revenue Service. Self-Employed Individuals – Calculating Your Own Retirement Plan Contribution and Deduction
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Internal Revenue Service. Retirement Plans Definitions
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Internal Revenue Service. The Plan Failed the 401(k) ADP and ACP Nondiscrimination Tests
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Internal Revenue Service. Issue Snapshot – Vesting Schedules for Matching Contributions
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Internal Revenue Service. Mid Year Changes to Safe Harbor 401(k) Plans and Notices
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Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
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Internal Revenue Service. 2026 Amounts Relating to Retirement Plans and IRAs, as Adjusted
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Internal Revenue Service. Consequences to a Participant Who Makes Excess Annual Salary Deferrals
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Internal Revenue Service. Retirement Plans FAQs on Designated Roth Accounts
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Internal Revenue Service. SECURE 2.0 Act Impacts How Businesses Complete Forms W-2
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Internal Revenue Service. Retirement Plans Startup Costs Tax Credit
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Internal Revenue Service. IRC 401(k) Plans – Establishing a 401(k) Plan
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U.S. Department of Labor Employee Benefits Security Administration. Understanding Your Responsibilities
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Internal Revenue Service. Retirement Topics – Prohibited Transactions
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DOL.gov. Protect Your Employee Benefit Plan With an ERISA Fidelity Bond
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Internal Revenue Service. Instructions for Form 5500-EZ
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Internal Revenue Service. Financial Advisors Are Assets in Your Clients One Participant Plans More Than 250000
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Internal Revenue Service. Retirement Topics – Plan Loans
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Internal Revenue Service. Retirement Topics – Exceptions to Tax on Early Distributions