ACA Requirements for Employers: Coverage, Reporting, and Penalties

If your business averaged 50 or more full-time employees last year, the Affordable Care Act requires you to offer affordable health coverage that meets minimum quality standards to at least 95% of those employees and their dependent children, report your offers to the IRS each year on Forms 1094-C and 1095-C, and pay per-employee penalties if you fall short. The ACA requirements for employers apply only above that 50-employee threshold, but once you cross it the exposure is real: for 2026, the harsher assessment reaches $3,340 per full-time employee.¹

Which Employers Are Covered

You’re an “applicable large employer” if your business employed an average of at least 50 full-time employees during the previous calendar year.² Full-time means averaging 30 or more hours of service per week, or 130 hours per month.³ That definition catches more workers than employers often expect, especially if you lean on staff working four six-hour shifts a week.

The 50-person count also folds in full-time equivalents. Add up the total monthly service hours of all part-time workers, divide by 120, and add the result to your actual full-time headcount for each month. Average those 12 monthly totals across the year. Hit 50, and you’re an applicable large employer for the following year.

Seasonal Worker Exception

If your workforce exceeds 50 full-time employees (including FTEs) for 120 days or fewer during the year, and the workers pushing you over are seasonal, you’re not treated as an applicable large employer.⁴ “Seasonal worker” generally follows the Department of Labor’s definition and includes retail workers employed exclusively during holiday seasons. The IRS allows a reasonable, good-faith interpretation of the term.

Related Companies Are Combined

You can’t sidestep the mandate by splitting employees across separate entities you control. Under Section 414 of the Internal Revenue Code, companies under common control are aggregated and treated as a single employer for the 50-employee threshold.⁵ The typical patterns are parent-subsidiary relationships involving 80% or greater ownership, and brother-sister groups where five or fewer owners collectively control two or more businesses. If the combined headcount reaches 50, every entity in the group is individually responsible for complying.

How To Measure Full-Time Status

The 30-hour standard is easy for salaried employees with fixed schedules. It gets complicated for variable-hour, seasonal, and part-time workers whose schedules move around. The IRS offers two approaches.³

Under the monthly measurement method, you determine each month whether an employee worked at least 130 hours. The look-back measurement method suits unpredictable schedules better. You track hours over a measurement period, typically 6 to 12 months, then lock in the employee’s status for a matching stability period. If a variable-hour employee averaged 30 or more hours during the measurement period, they must be treated as full-time and offered coverage throughout the stability period, even if their hours later drop. The look-back method decides who gets offered coverage; it does not decide whether you’re an applicable large employer in the first place.

What Coverage You Have To Offer

Applicable large employer status triggers two core obligations: offer coverage to the right people, and make sure that coverage meets specific quality benchmarks.

Who Has To Be Offered Coverage

You need to offer minimum essential coverage to at least 95% of your full-time workforce. The offer must also extend to employees’ dependent children up to age 26, married or not.⁶ The ACA does not require you to offer coverage to employees’ spouses, though many employers do.

Minimum Essential Coverage

This is the baseline category of health plan that satisfies the mandate. Most employer-sponsored major medical plans qualify. Limited-benefit plans that only cover specific conditions or services, such as standalone dental or vision, do not count.

Minimum Value

The plan must also give real financial protection. It meets the minimum value standard if it’s designed to cover at least 60% of the total allowed cost of benefits for a standard population.⁷ The IRS provides a minimum value calculator, and actuarial testing accounts for deductibles, copays, and coinsurance. A plan that technically qualifies as minimum essential coverage but shifts too much cost onto employees through high deductibles can still fail this test.

The 90-Day Waiting Period Cap

Even a compliant plan can’t keep eligible employees waiting too long. Federal regulations prohibit waiting periods longer than 90 calendar days, counting weekends and holidays, starting from the employee’s enrollment date.⁸ You can add an orientation period of up to one calendar month before the 90-day clock starts, and you can require cumulative hours-of-service conditions up to 1,200 hours. Once an employee meets your eligibility conditions, coverage must be available no later than the 91st day.

Affordability and the Safe Harbors

Offering a good plan isn’t enough if employees can’t afford to enroll. Coverage is “affordable” only if the employee’s required contribution for the lowest-cost self-only option doesn’t exceed a set percentage of household income. For 2026, that percentage is 9.96%.⁹ That’s a meaningful jump from the 8.39% threshold that applied in 2024, giving employers somewhat more room on premium contributions.

You almost certainly don’t know each employee’s household income, so the IRS lets you use one of three safe harbor proxies:

W-2 safe harbor. Affordability is measured against the wages reported in Box 1 of the employee’s Form W-2. The premium can’t exceed 9.96% of that amount.
Rate of pay safe harbor. You calculate affordability using the hourly rate multiplied by 130 monthly hours for hourly workers, or the monthly salary for salaried workers.
Federal poverty line safe harbor. You set a flat maximum premium based on the federal poverty level for a single individual. For 2026 calendar-year plans, that works out to roughly $129.90 per month, calculated using the 2025 mainland federal poverty line of $15,650.

Apply any safe harbor consistently and stay within the limit, and you’re protected from penalty even if the employee’s actual household income would have made coverage technically unaffordable. Most employers pick one method and apply it company-wide, but you can use different safe harbors for different employee categories.

Annual Reporting: Forms 1094-C and 1095-C

Applicable large employers file two IRS forms each year: Form 1094-C, the transmittal summary for the entire company, and Form 1095-C, an individual statement for each full-time employee.¹⁰ Self-insured employers must also report enrollment data for covered dependents in Part III of Form 1095-C, including names, Social Security numbers, and the months each person was enrolled.¹¹

The Coding on Part II

Part II of Form 1095-C requires two-character alphanumeric codes on Lines 14 and 16 for each month.¹¹ Line 14 uses codes like 1A through 1S to describe the coverage you offered, such as employee-only or employee plus dependents. Line 16 uses codes like 2A through 2I to explain circumstances, such as why an employee wasn’t enrolled. Getting these codes wrong is one of the most common triggers for erroneous penalty notices, because the IRS reads them as your official compliance statement.

Furnishing Forms to Employees

Beginning with the 2024 tax year, employers no longer have to automatically mail Form 1095-C to every employee. You can satisfy the furnishing requirement by posting a clear, conspicuous notice on your company website telling employees they can request a copy.¹¹ The notice must go up no later than the furnishing deadline (typically early March) and stay accessible through October 15. If an employee requests their form, you must provide it within 30 days of the request or by January 31 of the filing year, whichever is later. Employers who don’t use the website notice method must still furnish the form by hand delivery or mail.

Filing Deadlines

Paper filings are due by February 28. Electronic filings are due by March 31 of the year following the calendar year being reported.¹⁰ As a practical matter, nearly every applicable large employer must file electronically: the IRS requires e-filing for any organization submitting 10 or more information returns of any type during the calendar year.¹² Since that threshold aggregates W-2s and 1099s with 1095-Cs, any employer with 50-plus employees will easily exceed it. Electronic filing goes through the IRS Affordable Care Act Information Returns (AIR) system, and tracking your submission confirmation is the simplest way to prove timely filing if questions arise later.

Penalties for Falling Short

The IRS enforces the employer mandate through two assessments, often called the Part A and Part B penalties. Both are annual amounts calculated per employee, and both can escalate quickly.

Part A: Not Offering Coverage

If you fail to offer minimum essential coverage to at least 95% of your full-time employees and their dependent children, you face the broader penalty. For 2026, it’s $3,340 per full-time employee per year, minus the first 30 employees.¹ The 30-employee reduction applies to the total count, not to each location or entity.¹³ This penalty is triggered when even one full-time employee goes to the marketplace and receives a premium tax credit. For a company with 200 full-time employees, that comes to $567,800 annually — $3,340 multiplied by 170 employees after the reduction.

Part B: Inadequate or Unaffordable Coverage

If you do offer coverage but it fails minimum value or affordability, the penalty is $5,010 per year for each full-time employee who declines your plan and receives a premium tax credit on the marketplace.¹ Unlike Part A, Part B only applies to the specific employees who got subsidized marketplace coverage, not the entire workforce. The total Part B assessment is capped at whatever the Part A penalty would have been, so it never exceeds the broader amount.

How the IRS Notifies You

The IRS identifies potential penalties by cross-referencing the data on your 1094-C and 1095-C filings against individual tax returns filed by your employees. If the data suggests a liability, the IRS sends Letter 226-J proposing an employer shared responsibility payment.¹⁴ You have 90 days from the date printed on the letter to respond, not 90 days from when you receive it. That distinction matters because mail delays can eat into the response window. The letter breaks the proposed penalty down by employee and by month. In many cases the assessment stems from coding errors on the 1095-C rather than an actual coverage failure, which is why reviewing the letter line by line against your records is worth doing before paying anything.

Where Employers Actually Slip Up

The common compliance failures aren’t dramatic. Employers miscategorize variable-hour workers, miss the 95% offer threshold by overlooking a handful of employees, or file 1095-Cs with the wrong offer codes. Tracking hours throughout the year rather than scrambling at year-end, and running a mid-year audit of who has and hasn’t been offered coverage, will head off most of these problems before they generate a Letter 226-J. If your workforce fluctuates near the 50-employee line, set up a monthly headcount process that includes the FTE calculation so your applicable large employer status for the next year is never a surprise.

1
Internal Revenue Service. Rev. Proc. 2025-26
2
Office of the Law Revision Counsel. 26 U.S. Code 4980H – Shared Responsibility for Employers Regarding Health Coverage
3
Internal Revenue Service. Identifying Full-Time Employees
4
Internal Revenue Service. Questions and Answers on Employer Shared Responsibility Provisions Under the Affordable Care Act
5
Office of the Law Revision Counsel. 26 U.S. Code 414 – Definitions and Special Rules
6
U.S. Department of Labor. Young Adults and the Affordable Care Act
7
Internal Revenue Service. Minimum Value and Affordability
8
eCFR. 26 CFR 54.9815-2708 – Prohibition on Waiting Periods That Exceed 90 Days
9
Internal Revenue Service. Rev. Proc. 2025-25
10
Internal Revenue Service. Questions and Answers About Information Reporting by Employers on Form 1094-C and Form 1095-C
11
Internal Revenue Service. 2025 Instructions for Forms 1094-C and 1095-C
12
Internal Revenue Service. E-File Information Returns
13
Internal Revenue Service. Employer Shared Responsibility Provisions
14
Internal Revenue Service. Understanding Your Letter 226-J