Retirement Plans for Business Owners: SEP, SIMPLE, Solo 401(k)

Retirement Plans for Business Owners: SEP, SIMPLE, Solo 401(k)

Retirement plan contributions are one of the most powerful tax deductions available to business owners. You reduce your taxable income today while building wealth for the future. The challenge is choosing the right plan for your situation.

Why Retirement Plans Matter for Taxes

Every dollar you contribute to a qualified retirement plan reduces your taxable income for the year. If you are in the 32% tax bracket and contribute $50,000 to a SEP IRA, you save $16,000 in federal income tax. For self-employed individuals, the contributions also reduce your self-employment tax base.

Contributions grow tax-deferred until retirement. You pay income tax only when you withdraw the funds, ideally when you are in a lower tax bracket.

The Tax Savings Are Immediate and Substantial

Net Business Income	Max Retirement Contribution	Tax Savings (24% bracket)	Tax Savings (32% bracket)
$50,000	~$9,300 (SEP) / ~$32,800 (Solo 401k)	$2,232 / $7,872	$2,976 / $10,496
$100,000	~$18,600 (SEP) / ~$42,100 (Solo 401k)	$4,464 / $10,104	$5,952 / $13,472
$150,000	~$27,900 (SEP) / ~$51,400 (Solo 401k)	$6,696 / $12,336	$8,928 / $16,448
$200,000	~$37,200 (SEP) / ~$60,700 (Solo 401k)	$8,928 / $14,568	$11,904 / $19,424
$300,000	~$55,800 (SEP) / ~$70,000 (Solo 401k)	$13,392 / $16,800	$17,856 / $22,400

These figures include the income tax savings only. For sole proprietors and partners, the SE tax savings push the total benefit even higher.

SEP IRA (Simplified Employee Pension)

A SEP IRA is the simplest retirement plan for self-employed individuals and small business owners.

Key Features

• Contribution limit: Up to 25% of net self-employment earnings (after the SE tax deduction), maximum $70,000 for 2025
• Who contributes: Employer only (you, as the business owner)
• Employee requirement: If you have eligible employees, you must contribute the same percentage for them as you do for yourself
• Setup deadline: Can be established and funded as late as the tax filing deadline (including extensions)
• Administration: Minimal paperwork, no annual IRS filings
• Investment options: Open at any brokerage (Vanguard, Fidelity, Schwab, etc.) with access to stocks, bonds, mutual funds, ETFs

SEP IRA Contribution Limits by Year

Year	Maximum Contribution	Maximum Compensation Considered
2023	$66,000	$330,000
2024	$69,000	$345,000
2025	$70,000	$350,000

Calculating Your SEP IRA Contribution (Self-Employed)

The calculation for self-employed individuals is not as straightforward as "25% of net income." Here is the actual formula:

1. Start with net self-employment income
2. Subtract half of your self-employment tax (the deductible portion)
3. Multiply by 25% (or use the IRS rate table factor of 20% of net SE income as a shortcut)

Example at $120,000 net SE income:

• SE tax: $120,000 x 92.35% x 15.3% = $16,955
• Deductible half of SE tax: $8,478
• Adjusted net SE income: $120,000 - $8,478 = $111,522
• Maximum SEP contribution: $111,522 x 25% = $27,881
• Shortcut: $120,000 x 20% = $24,000 (close approximation)

The effective contribution rate for self-employed individuals works out to approximately 18.6% of net SE income (not 25%). The 25% rate applies to W-2 wages for employees.

Best For

Solo business owners or businesses with few employees who want simplicity and high contribution limits. The SEP is ideal if you want to make a large contribution in a profitable year and skip contributions in a lean year -- contributions are completely discretionary.

Watch Out For

If you have employees, the equal percentage requirement can make a SEP expensive. Contributing 25% of your own income means contributing 25% of every eligible employee's compensation as well.

Example: You earn $200,000 and have two employees earning $50,000 each. To contribute 25% for yourself ($37,200 using the self-employed formula), you must also contribute 25% for each employee: $50,000 x 25% = $12,500 each, or $25,000 total. Your personal deduction costs an additional $25,000 in employer contributions.

SIMPLE IRA (Savings Incentive Match Plan for Employees)

The SIMPLE IRA is designed for businesses with 100 or fewer employees.

Key Features

• Employee contribution limit: $16,500 for 2025 ($20,000 if age 50+)
• Employer contribution: Either match employee contributions dollar-for-dollar up to 3% of compensation, or make a 2% non-elective contribution for all eligible employees
• Who contributes: Both employer and employee
• Setup deadline: Must be established by October 1 of the year (for existing businesses)
• Administration: Low paperwork, no annual IRS filings
• Early withdrawal penalty: 25% if withdrawn within first 2 years (vs. 10% for other plans)

SIMPLE IRA Employer Matching Options

Option 1: Dollar-for-Dollar Match (up to 3%) You match what each employee contributes, up to 3% of their compensation. If an employee earns $60,000 and contributes 3% ($1,800), you match $1,800. If they contribute nothing, you match nothing. This is the most common option.

You can reduce the match to as low as 1% in up to two out of any five years. This gives you flexibility in lean years.

Option 2: 2% Non-Elective Contribution You contribute 2% of every eligible employee's compensation regardless of whether they make their own contributions. For an employee earning $60,000, you contribute $1,200 whether they participate or not.

SIMPLE IRA vs. Traditional IRA

Feature	SIMPLE IRA	Traditional IRA
2025 contribution limit	$16,500	$7,000
Catch-up (50+)	$3,500	$1,000
Employer contributions	Yes	No
Income limits for deduction	None	Yes (if covered by workplace plan)
Early withdrawal penalty	25% (first 2 years)	10%
Required for employees	Must offer to eligible employees	Individual decision

Best For

Small businesses that want employees to participate in saving for retirement with modest employer costs. The SIMPLE works well when you want to contribute more than a traditional IRA allows but do not need the high limits of a SEP or Solo 401(k).

Watch Out For

The contribution limit is significantly lower than a SEP or Solo 401(k). You cannot have a SIMPLE IRA and another employer-sponsored plan in the same year. The 25% early withdrawal penalty in the first two years is unusually harsh.

Solo 401(k)

The Solo 401(k) -- also called an Individual 401(k) -- is available to self-employed individuals with no employees (other than a spouse).

Key Features

• Employee deferral: Up to $23,500 for 2025 ($31,000 if age 50+; $27,750 if age 60-63 under SECURE 2.0)
• Employer contribution: Up to 25% of net self-employment earnings (after SE tax deduction)
• Total maximum: $70,000 for 2025 ($77,500 if age 50+)
• Roth option: Many Solo 401(k) plans allow Roth (after-tax) contributions
• Loan provision: You can borrow up to $50,000 or 50% of the account balance (if the plan allows)
• Setup deadline: Must be established by December 31 of the tax year (contributions can be made until tax filing deadline)

Why the Solo 401(k) Shelters More Income at Lower Earnings

The Solo 401(k) has a major advantage over the SEP IRA at lower and moderate income levels: the employee deferral component.

Example at $70,000 net self-employment income:

	SEP IRA	Solo 401(k)
Employee deferral	$0	$23,500
Employer contribution (approx.)	$13,020	$13,020
Total contribution	$13,020	$36,520
Tax savings (24% bracket)	$3,125	$8,765

The Solo 401(k) allows nearly three times the contribution at this income level. The difference narrows as income increases, and both plans hit the same $70,000 cap at high incomes.

Solo 401(k) Contribution Calculation Example

Net SE income: $150,000

1. Employee deferral: $23,500 (the flat maximum, regardless of income)
2. Calculate employer contribution base: $150,000 - ($150,000 x 92.35% x 15.3% / 2) = $150,000 - $10,597 = $139,403
3. Employer contribution: $139,403 x 25% = $34,851
4. Total: $23,500 + $34,851 = $58,351

If you are age 50+, add the $7,500 catch-up: $58,351 + $7,500 = $65,851.

Best For

Self-employed individuals and freelancers with no employees who want to maximize contributions. The combination of employee deferrals and employer contributions allows you to shelter more income than a SEP at the same income level.

Watch Out For

Once you hire employees (other than a spouse), you can no longer use a Solo 401(k). You will need to switch to a different plan. Annual IRS filing (Form 5500-EZ) is required once the plan assets exceed $250,000.

Roth vs. Traditional Contributions: Which Is Better?

The Solo 401(k) and some newer SIMPLE IRA plans offer a Roth option. The choice between traditional (pre-tax) and Roth (after-tax) contributions depends on your current vs. future tax rate:

Factor	Traditional (Pre-Tax)	Roth (After-Tax)
Tax benefit timing	Deduction now, taxed at withdrawal	No deduction now, tax-free at withdrawal
Best when	Current tax rate is higher than expected retirement rate	Current tax rate is lower than expected retirement rate
RMDs (Required Minimum Distributions)	Yes, starting at age 73	No RMDs for Roth 401(k) as of 2024
Income tax on growth	Yes, at withdrawal	No
Reduces AGI now	Yes	No
Reduces QBI deduction threshold	Yes (lower AGI)	No (AGI stays higher)

Practical guidance for business owners: If your business income is high now and you expect lower income in retirement, traditional contributions make sense -- you deduct at 32-37% now and pay tax at 12-22% later. If your income is currently moderate (22-24% bracket) and you expect it to grow, Roth contributions lock in the lower rate.

Many advisors recommend a mix of both for diversification.

Plan Comparison

Feature	SEP IRA	SIMPLE IRA	Solo 401(k)
Max contribution (2025)	$70,000	$16,500 + match	$70,000
Catch-up (50+)	None	$3,500	$7,500
Employee deferrals	No	Yes	Yes
Roth option	No	Limited (new SECURE 2.0)	Yes (if offered)
Loans	No	No	Yes (if offered)
Employees allowed	Yes	Yes (under 100)	No (except spouse)
Setup deadline	Tax filing deadline	October 1	December 31
Annual IRS filing	No	No	Over $250k assets
Discretionary contributions	Yes	Employer match portion only	Yes (employer portion)
Equal treatment of employees	Required	Required	N/A (no employees)

Choosing the Right Plan

Solo with high income, no employees: Solo 401(k). You get the highest contribution limits and the most flexibility (Roth option, loans).

Solo with moderate income: Solo 401(k) still wins at moderate income because the employee deferral lets you contribute more. SEP IRA is a good alternative if you want zero administration.

Business with employees: SIMPLE IRA if you want low cost and simplicity. SEP IRA if you want higher contribution limits and are willing to contribute the same percentage for employees. Consider a traditional 401(k) if you have more than a few employees and want more sophisticated plan design.

Late in the tax year: SEP IRA is the only option you can set up after year-end (up to the filing deadline including extensions). If it is December and you have not set up a plan, open a SEP.

Decision Flowchart

1. Do you have employees (other than a spouse)? -> If yes, go to step 2. If no, go to step 3.
2. How many employees? Under 100 -> SIMPLE IRA (low cost) or SEP IRA (higher contribution limits). Over 100 -> Traditional 401(k).
3. Is it before December 31? -> If yes, Solo 401(k) (maximum flexibility and contribution). If no, SEP IRA (can be set up until filing deadline).

Common Retirement Plan Mistakes

1. Not Contributing at All

The biggest mistake is not starting. Even small contributions grow significantly over time. Contributing $10,000 per year at 8% average return for 20 years yields approximately $494,000. At 30 years, it grows to $1,223,000. Start with whatever you can afford and increase annually.

2. Contributing to a SEP When a Solo 401(k) Would Allow More

At $80,000 in net SE income, a SEP allows roughly $14,900 in contributions. A Solo 401(k) allows approximately $38,400 (including the $23,500 employee deferral). That is $23,500 more in tax-deferred savings -- and $5,640 more in tax savings at the 24% bracket.

3. Missing Contribution Deadlines

• Solo 401(k) employee deferrals: December 31
• Solo 401(k) employer contributions: Tax filing deadline (including extensions)
• SEP IRA: Tax filing deadline (including extensions)
• SIMPLE IRA employee deferrals: 30 days after the calendar month they were deferred
• SIMPLE IRA employer match: Tax filing deadline (including extensions)

4. Not Considering the Spousal Contribution

If your spouse works in your business, they can also make employee deferrals to a Solo 401(k). This effectively doubles the deferral limit. A married couple with a profitable business can contribute up to $140,000 per year ($70,000 each) to a Solo 401(k).

5. Ignoring State Tax Savings

Retirement contributions reduce your state income tax too. In California (13.3% top rate), a $50,000 contribution saves up to $6,650 in state taxes on top of the federal savings. In New York (10.9%), it saves up to $5,450.

Implementation Steps

1. Choose the plan that matches your business structure and goals
2. Open the account with a brokerage or financial institution (Vanguard, Fidelity, and Schwab all offer free SEP and Solo 401(k) plans)
3. Adopt the plan document (provided by the custodian)
4. Make contributions by the applicable deadline
5. Report contributions on your tax return (Form 1040, Schedule 1, line 16 for SEP/Solo 401k)
6. If you have employees, provide required notices and disclosures
7. File Form 5500-EZ annually once Solo 401(k) assets exceed $250,000

Where to Open Each Plan Type

Plan	Recommended Providers	Setup Cost	Annual Fees
SEP IRA	Vanguard, Fidelity, Schwab	Free	None (fund-level fees only)
SIMPLE IRA	Vanguard, Fidelity, Schwab	Free	None (fund-level fees only)
Solo 401(k)	Fidelity, Schwab, Vanguard	Free	None at these providers
Solo 401(k) with Roth	Fidelity, Schwab	Free	None at these providers
Solo 401(k) with loans	E*TRADE, Nabers Group, MySolo401k	$0-$500	$0-$200/year

Consult with a financial advisor or CPA to run the numbers for your specific income level. The difference between plans can mean thousands of dollars in tax savings and retirement accumulation.

SECURE 2.0 Act: Key Changes for Small Business Retirement Plans

The SECURE 2.0 Act (passed in 2022, with provisions phasing in through 2027) made several important changes for small business retirement plans:

Enhanced Startup Credit

Small businesses with up to 50 employees can now receive a tax credit covering 100% of plan startup costs (up to $5,000 per year for 3 years). This means the first three years of plan administration costs are essentially free.

Employer Matching to Roth Accounts

Starting in 2024, employers can make matching and non-elective contributions to designated Roth accounts (previously, employer contributions had to be pre-tax). This gives employees the option to pay tax on employer contributions now for tax-free growth.

Increased Catch-Up Contributions (Ages 60-63)

Starting in 2025, employees ages 60-63 can make catch-up contributions of the greater of $10,000 or 150% of the regular catch-up limit. For 2025, this means catch-up contributions of up to $11,250 (instead of $7,500) for 401(k) plans for those in the 60-63 age range.

Automatic Enrollment (New Plans)

New 401(k) and 403(b) plans established after December 29, 2022 must include automatic enrollment (starting at 3-10% of salary, increasing 1% annually up to 10-15%). Exemptions apply to businesses with 10 or fewer employees, businesses less than 3 years old, and SIMPLE plans.

Student Loan Match

Employers can now make matching contributions to retirement accounts based on employees' student loan payments, treating the loan payments as if they were elective deferrals.

Retirement Plans and the QBI Deduction Connection

Retirement contributions interact with the Qualified Business Income (QBI) deduction in an important way. For pass-through business owners, retirement contributions reduce your taxable income, which can affect your QBI deduction calculation:

If you are below the QBI income threshold: Retirement contributions reduce your taxable income but have minimal impact on the QBI deduction itself (since you qualify for the full 20% regardless).

If you are near the QBI phase-out threshold (specified service businesses): Retirement contributions can push your taxable income below the phase-out range, preserving the full 20% QBI deduction. This creates a double benefit -- the deduction from the contribution itself plus the preserved QBI deduction.

Example: A single consultant with $200,000 in QBI and $210,000 in taxable income. Taxable income exceeds the 2025 threshold of $191,950 for specified service businesses, so the QBI deduction is partially reduced. By contributing $23,500 to a Solo 401(k), taxable income drops to $186,500 -- below the threshold -- and the full QBI deduction of $40,000 (20% of $200,000) is preserved. The retirement contribution effectively provides:

• $5,640 in income tax savings (24% bracket)
• $8,000 in preserved QBI deduction benefit (rough estimate)
• $13,640+ in total tax benefit from a single $23,500 contribution

The Long-Term Math: Why Starting Early Matters

The tax deduction is immediate, but the real wealth-building happens over time through tax-deferred (or tax-free, with Roth) compound growth:

Annual Contribution	10 Years (at 8%)	20 Years (at 8%)	30 Years (at 8%)
$10,000	$156,455	$494,229	$1,223,459
$25,000	$391,137	$1,235,573	$3,058,648
$50,000	$782,274	$2,471,146	$6,117,296
$70,000 (max)	$1,095,184	$3,459,604	$8,564,215

A business owner contributing the maximum $70,000 per year (Solo 401(k) or SEP IRA at high income) for 20 years, earning an average 8% return, accumulates over $3.4 million -- all while reducing their tax bill by $16,800-$25,900 every single year.

Even modest contributions add up. Contributing $10,000 per year for 20 years yields nearly $500,000. The tax deduction makes the effective cost of that $10,000 contribution only $6,000-$7,600 (depending on your bracket), because the tax savings subsidize a significant portion.