A Section 125 plan and ACA compliance are two separate rules that meet in one number: the amount an employee has to pay out of their own pay for self-only coverage. Section 125 decides whether that amount comes out before tax, and the Affordable Care Act decides whether that amount is small enough to keep the employer out of a penalty.
Most small and mid-size employers set up the cafeteria plan for the tax savings and never connect it to the employer mandate. That is where the exposure starts. This guide walks the connection point by point, with the 2026 and 2027 dollar figures, and shows what an applicable large employer needs in writing.
Key Facts
- The ACA required contribution percentage is 9.96% for plan years beginning in 2026 (IRS Revenue Procedure 2025-25) and 10.22% for plan years beginning in 2027 (IRS Revenue Procedure 2026-26).
- The 2026 federal poverty guideline for one person in the 48 contiguous states is $15,960 (HHS annual update published January 15, 2026).
- The Section 4980H(a) penalty is $3,340 per full-time employee for 2026 and $3,780 for 2027 (IRS Revenue Procedures 2025-26 and 2026-22).
- The Section 4980H(b) penalty is $5,010 per subsidized employee for 2026 and $5,670 for 2027 (IRS Revenue Procedures 2025-26 and 2026-22).
- Affordability is measured on "the portion of the annual premium the employee must pay, whether by salary reduction or otherwise," per 26 CFR 1.36B-2(c)(3)(v)(A).
- An employer must have a written cafeteria plan document adopted on or before the first day of the plan year for pre-tax treatment to hold, per Proposed Treasury Regulation 1.125-1(c) (2007).
What does a Section 125 plan have to do with ACA compliance?
A Section 125 plan is the legal mechanism that turns an employee's premium share into a pre-tax salary reduction, and that salary reduction is the number the ACA affordability test looks at. Without a written Section 125 cafeteria plan, an employer cannot take the employee's premium contribution out before federal income tax, Social Security and Medicare. The money would have to come out after tax instead.
Section 125 is the part of the Internal Revenue Code that lets employees choose between cash wages and certain non-taxable benefits without being taxed on the choice itself. IRS Publication 15-B (2026) defines a cafeteria plan as a written plan that lets employees choose between receiving cash or taxable benefits and certain qualified benefits the law excludes from wages.
The ACA employer mandate, in Internal Revenue Code Section 4980H, is a separate rule. It applies to an applicable large employer, meaning one that averaged 50 or more full-time and full-time equivalent employees in the prior calendar year. That employer must offer minimum essential coverage that is both affordable and of minimum value to substantially all full-time employees, as set out in the ACA employer mandate requirements.
The two rules meet because affordability is defined by what the employee pays. Under 26 CFR 1.36B-2(c)(3)(v)(A), the employee required contribution is "the portion of the annual premium the employee must pay, whether by salary reduction or otherwise, for self-only coverage." If the employer runs premiums through a cafeteria plan, the salary reduction is the required contribution. Learn the mechanics of the plan itself in the Section 125 cafeteria plan guide.
How much can an employee be charged before coverage is unaffordable?
An employee's share of self-only coverage must stay at or below 10.22% of the measure chosen under a safe harbor for plan years beginning in 2027, down from a 9.96% ceiling for plan years beginning in 2026. IRS Revenue Procedure 2025-25 set the 9.96% figure for 2026 and IRS Revenue Procedure 2026-26 set 10.22% for 2027.
The percentage applies to household income, which no employer can see. That is why the IRS provides three safe harbors that substitute a number the employer already has.
| Safe harbor | What it measures | Best for |
|---|---|---|
| Form W-2 | Box 1 wages for the current year | Salaried staff with steady pay |
| Rate of pay | Hourly rate x 130 hours, or monthly salary | Hourly staff with variable hours |
| Federal poverty line | The FPL for one person, divided by 12 | Employers who want one number for everyone |
The federal poverty line safe harbor is the one most small employers use, because it produces a single monthly ceiling that applies to the whole workforce. Under 26 CFR 54.4980H-5(e)(2)(iv), the monthly amount is the federal poverty line for a single individual divided by 12. The employer may use the poverty guidelines in effect within six months before the first day of the plan year, per 26 CFR 54.4980H-1(a)(19).
For a calendar-year 2027 plan, that means the 2026 guideline of $15,960 multiplied by 10.22%, then divided by 12. The result is $135.92 per month. An employer that charges no more than $135.92 for self-only coverage in 2027 meets the affordability test for every full-time employee, regardless of what any individual earns. The ACA affordability percentage guide tracks the percentage history year by year.
Table: Federal poverty line safe harbor ceiling, calendar-year plans
| Plan year | Required contribution percentage | FPL used | Monthly ceiling |
|---|---|---|---|
| 2026 | 9.96% (Rev. Proc. 2025-25) | 2025 guideline | See the affordability guide |
| 2027 | 10.22% (Rev. Proc. 2026-26) | $15,960 (2026 guideline) | $135.92 |
How do employer flex credits change the employee required contribution?
An employer flex credit reduces the employee required contribution only if it is a health flex contribution, which means the employee cannot take it as cash and can use it only for medical care. IRS Notice 2015-87, Q&A-8, sets a three-part test: the employee may not opt to receive the amount as a taxable benefit, the employee may use the amount to pay for minimum essential coverage, and the employee may use the amount exclusively to pay for medical care.
This catches employers more than any other rule in this area. A cafeteria plan that gives every employee a $200 monthly benefit allowance they can spend on health premiums, a dependent care account, or take as extra pay is not a health flex contribution. The employee could take the cash. Notice 2015-87 is direct on the result: an employer flex contribution that is not a health flex contribution does not reduce an employee's required contribution.
Here is what that does to the math.
Table: Same $200 allowance, two different affordability outcomes
| Plan design | Monthly premium for self-only | Flex credit | Employee required contribution |
|---|---|---|---|
| Credit usable only for medical care | $320 | $200 | $120 |
| Credit can be taken as cash | $320 | $200 | $320 |
The first design clears the 2027 FPL safe harbor ceiling of $135.92. The second does not, and the gap is $184.08 per month per employee. Nothing about the employee's actual paycheck changed. Only the plan document language did.
Do opt-out payments count against affordability?
An unconditional opt-out payment increases the employee required contribution, because the IRS treats it the same as a salary reduction. IRS Notice 2015-87, Q&A-9, applies this to a payment conditioned solely on an employee declining coverage and not on satisfying any other meaningful requirement. The logic is that an employee who takes the coverage gives up the cash, so the cash is part of the real price of coverage.
A conditional arrangement is treated differently. Under proposed regulations issued in 2016 (REG-109086-15), an eligible opt-out arrangement conditions the payment on the employee declining employer coverage and providing reasonable evidence that the employee and the employee's expected tax family have or will have other minimum essential coverage. Payments under an eligible opt-out arrangement are excluded from the required contribution. These rules are still proposed, and the final regulation at 26 CFR 1.36B-2(c)(3)(v)(A)(6) remains reserved, so an employer relying on them should document the evidence it collects. The opt-out payments and ACA affordability guide works through the full example.
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Can an employer let employees buy a marketplace plan through a Section 125 plan?
No. Internal Revenue Code Section 125(f)(3)(A) states that a qualified benefit does not include any qualified health plan offered through an Exchange established under Section 1311 of the Affordable Care Act. An employer cannot run an employee's individual marketplace premium through a cafeteria plan and call it pre-tax.
Section 125(f)(3)(B) carves out one exception. The prohibition does not apply where the employer is a qualified employer under Section 1312(f)(2) of the ACA offering the employee the chance to enroll through an Exchange in a qualified health plan in the group market, which is the SHOP route.
This is also why an individual coverage HRA has its own set of rules. Off-exchange individual premiums above the ICHRA allowance can run through a premium only plan pre-tax, while on-exchange marketplace premiums cannot. That distinction is worked through in the ICHRA and Section 125 premium only plan guide.
What do the ACA penalties cost if the plan fails?
The Section 4980H(a) penalty is $3,340 per full-time employee for 2026 and $3,780 for 2027, and the Section 4980H(b) penalty is $5,010 per subsidized employee for 2026 and $5,670 for 2027. IRS Revenue Procedure 2025-26 set the 2026 amounts and IRS Revenue Procedure 2026-22 set the 2027 amounts.
The two penalties work differently, and the difference matters when an employer is deciding how much risk an unaffordable contribution actually carries.
Table: ACA employer shared responsibility penalties
| Penalty | Trigger | 2026 amount | 2027 amount | Counted on |
|---|---|---|---|---|
| 4980H(a) | Failing to offer coverage to substantially all full-time employees, and at least one gets a premium tax credit | $3,340 | $3,780 | Every full-time employee, minus the first 30 |
| 4980H(b) | Offering coverage that is unaffordable or not minimum value, and an employee gets a premium tax credit | $5,010 | $5,670 | Only the employees who received a credit |
Note that the IRS employer shared responsibility question and answer page has not been updated past 2023 amounts. Use the revenue procedures for 2026 and 2027 figures.
Here is what the second penalty looks like in practice. A 60-employee company charges $185 per month for self-only coverage in 2027 and uses the federal poverty line safe harbor. The ceiling is $135.92, so the offer is unaffordable by $49.08 per month. Eight employees go to the marketplace and receive a premium tax credit. The 4980H(b) exposure is 8 x $5,670, which is $45,360 for the year. Lowering the contribution to $135 per month for all 60 employees costs the employer 60 x $50 x 12, which is $36,000, and removes the penalty entirely.
Since December 2024, an employer has at least 90 days to respond to a proposed assessment under the Employer Reporting Improvement Act (Public Law 118-168), and a six-year statute of limitations now applies to those assessments. The IRS Letter 226-J guide covers what the notice looks like when it arrives.
What Section 125 paperwork does an ACA-compliant employer need?
An employer needs a written cafeteria plan document adopted and effective on or before the first day of the plan year it covers. Proposed Treasury Regulation 1.125-1(c), issued in 2007, requires the document to describe each benefit and period of coverage, the participation rules, the election procedures and election periods, the irrevocability rule, the manner and maximum of employer contributions, and the plan year.
Elections are locked once made. Under 26 CFR 1.125-4, a cafeteria plan may allow an employee to revoke an election mid-year only for a listed event, including HIPAA special enrollment rights, a change in status such as marriage or birth, a judgment or decree, Medicare or Medicaid entitlement, a significant cost or coverage change, and FMLA leave. Failing the written document requirement does not just break Section 125. It makes every employee election taxable and leaves the employer with underwithheld payroll taxes.
The practical checklist below is the one to run before an ACA plan year starts.
- Confirm the cafeteria plan document is signed and dated before the plan year begins.
- Write down which affordability safe harbor the company is using and why.
- Calculate the self-only employee contribution for the lowest-cost minimum value plan and compare it to the safe harbor ceiling.
- Check whether any flex credit passes the three-part health flex contribution test in Notice 2015-87 Q&A-8.
- Check whether any opt-out payment is unconditional, and if so add it to the required contribution.
- Confirm no employee is being offered an exchange plan through the cafeteria plan, outside the SHOP exception.
- Reconcile the contribution used on Line 15 of Form 1095-C with what payroll actually deducted.
What does the Section 125 side of this save?
A Section 125 plan removes 7.65% employer FICA from every pre-tax election dollar, which is the part of this that pays for itself. FICA is the combined Social Security tax of 6.2% and Medicare tax of 1.45%, and the employer pays a matching 7.65% on the same wages, per IRS Publication 15 (2026). The Social Security wage base for 2026 is $184,500.
For a typical employer, Summit Health Benefits sees FICA recapture of $91 to $136 per enrolled employee per month. The Summit administration fee is $35 per enrolled employee per month, paid out of that recaptured FICA rather than operating cash, so the employer still nets roughly $56 to $101 per enrolled employee per month. Employees see take-home pay rise by roughly $70 to $110 per month, because the same premium now comes out before tax instead of after.
Take the 60-employee company above. Moving the self-only contribution to $135 per month and running all 60 through a Section 125 plan produces $135 x 60 x 12 x 7.65%, which is $7,436 per year in recaptured employer FICA. That offsets a meaningful share of the $36,000 contribution reduction while eliminating a $45,360 penalty. The FICA savings breakdown shows the full calculation. Employers who want to model their own roster can run the numbers on the Section 125 savings calculator.
Copy and paste: the ACA affordability self-test
Run this on the lowest-cost self-only plan you offer, for the plan year that is about to start.
- Monthly employee contribution for self-only, lowest-cost minimum value plan: $______
- Safe harbor chosen (W-2, rate of pay, or federal poverty line): ______
- Safe harbor ceiling for that plan year: $______ (federal poverty line safe harbor for calendar-year 2027 is $135.92)
- Any flex credit that passes all three parts of the Notice 2015-87 Q&A-8 test: minus $______
- Any unconditional opt-out payment: plus $______
- Line 1 minus line 4 plus line 5 = adjusted required contribution: $______
- Is line 6 at or below line 3? If no, count your full-time employees likely to claim a premium tax credit and multiply by the 4980H(b) amount for that year.
Find out if your plan passes the ACA affordability test
A benefits advisor reviews your current employee contribution, your plan document and your safe harbor choice, and tells you where you stand before the IRS does.
Frequently Asked Questions
Does a Section 125 plan make an employer ACA compliant?
What is the Section 125 plan ACA affordability percentage for 2027?
Do employer flex credits count toward ACA affordability?
Can an employer offer a marketplace plan through a cafeteria plan?
What is the ACA penalty if a Section 125 contribution is too high?
Does an employer need a written Section 125 plan document?
Can employees change a Section 125 election mid-year for an ACA reason?
Which affordability safe harbor should a small employer use?
Sources: IRS Revenue Procedure 2025-25 (2026 required contribution percentage); IRS Revenue Procedure 2026-26 (2027 required contribution percentage); IRS Revenue Procedure 2025-26 (2026 Section 4980H penalty amounts); IRS Revenue Procedure 2026-22 (2027 Section 4980H penalty amounts); U.S. Department of Health and Human Services, Annual Update of the HHS Poverty Guidelines, published January 15, 2026; IRS Notice 2015-87, Q&A-8 and Q&A-9; Proposed Treasury Regulation Section 1.36B-2(c)(3)(v)(A)(6), REG-109086-15 (2016); 26 CFR 1.36B-2(c)(3)(v)(A); 26 CFR 54.4980H-1(a)(19) and 54.4980H-5(e)(2)(iv); Internal Revenue Code Section 125(f)(3); Proposed Treasury Regulation 1.125-1(c) (2007); 26 CFR 1.125-4; IRS Publication 15-B (2026); IRS Publication 15 (2026); Employer Reporting Improvement Act, Public Law 118-168 (2024).