A single botched code on Line 16 of a Form 1095-C can cost an employer thousands of dollars per employee. For a company with 200 full-time workers and one systemic coding error, that's a tax bill north of half a million dollars — and the IRS is sending more of these letters than ever as it works through the backlog of 2022, 2023, and 2024 reporting years.
If your business crossed the 50 full-time-employee line, you are an Applicable Large Employer (ALE). That means you owe two things to the IRS every year: a properly coded Form 1095-C for every full-time worker, and an offer of affordable, minimum-value health coverage to at least 95 percent of them. Skip either obligation and Section 4980H of the Internal Revenue Code lets the IRS assess two of the steepest per-employee penalties in the tax code — penalties that grow with the medical inflation index every single year.
This guide walks through who owes what, how the 2026 numbers shake out, which safe harbors actually protect you, and the coding mistakes that quietly inflate Letter 226-J assessments long after the filing deadline has passed.
Who counts as an Applicable Large Employer
The 50-employee threshold sounds simple, but the math behind it trips up plenty of growing companies. You are an ALE for 2026 if, during 2025, you averaged at least 50 full-time employees, including full-time-equivalents.
A full-time employee for ACA purposes works at least 30 hours per week or 130 hours per month. Full-time equivalents are calculated by taking the total monthly hours of all part-time employees (capped at 120 per person), dividing by 120, and adding the result to the full-time headcount. Two half-time workers count as one FTE.
A few details that catch employers off guard:
- Controlled groups aggregate: If a parent company and its subsidiaries share more than 50 percent common ownership, their headcounts combine. A 30-employee operating company owned by the same person as a 25-employee holding company is an ALE even though neither entity alone would qualify.
- Seasonal exception: If your headcount only exceeded 50 because of a four-month-or-less seasonal spike, you may not be an ALE.
- The first year is messy: A company that crosses the threshold for the first time in 2025 owes 2026 reporting and is subject to penalties starting in 2026 — there is no grace period beyond the original 2015 transition relief.
Once you are an ALE, you stay an ALE the following year regardless of headcount drops, and the obligations apply per ALE member of the controlled group.
The two penalties you have to avoid
Section 4980H creates two distinct penalties. They are sometimes called the "A penalty" and the "B penalty," and most employers are surprised by how the math compounds.
The 4980H(a) penalty — failing to offer coverage at all
The A penalty triggers when an ALE fails to offer minimum essential coverage (MEC) to at least 95 percent of its full-time employees and their dependent children, and at least one full-time employee receives a premium tax credit on a marketplace plan.
For 2026, the A penalty is $3,340 per full-time employee per year, calculated against your entire full-time headcount minus the first 30. That subtraction is one number, not 30 per ALE member of a controlled group — large multi-entity employers must allocate the 30-employee buffer across the group.
A company with 200 full-time employees that misses the 95-percent threshold for even one month and has one employee receiving a subsidy on the exchange faces a monthly assessment of $3,340 ÷ 12 × (200 − 30) = roughly $47,317 for that month alone. Annualized: about $567,800.
Note the all-or-nothing trigger. A single employee receiving a premium tax credit when you missed the 95-percent offer flips the switch for every full-time employee on the payroll.
The 4980H(b) penalty — offering coverage that is unaffordable
The B penalty applies when you cleared the 95-percent offer hurdle but the coverage you offered was either not affordable or did not provide minimum value, and a full-time employee receives a premium tax credit. The 2026 amount is $5,010 per affected full-time employee per year — $417.50 per month per employee.
Crucially, this penalty hits per-employee, not whole-workforce. If five employees receive premium tax credits because their share of the premium exceeded affordability, you owe roughly $25,050 for the year. Still painful, but proportional to your actual coverage gap rather than your full headcount.
The B penalty is also capped: it can never exceed what the A penalty would have been if you offered no coverage at all. That ceiling matters in edge cases.
Affordability: the 9.96 percent rule for 2026
Coverage is "affordable" under the ACA if the lowest-cost self-only minimum-value option does not require the employee to contribute more than a set percentage of household income. The IRS resets this percentage every year based on the premium adjustment factor.
For plan years beginning in 2026, the affordability percentage is 9.96 percent, up from 9.02 percent in 2025. The increase actually loosens the constraint slightly — employers can charge a little more for employee-only coverage and still stay safe.
Household income is unknowable to employers, so the regulations provide three optional safe harbors. Pick whichever fits your workforce; you can use different safe harbors for different employee classes as long as you apply the chosen method uniformly within each class.
Federal Poverty Line safe harbor
The simplest method. For 2026, employee contributions for the lowest-cost self-only minimum-value plan are deemed affordable if they do not exceed $129.89 per month, based on the 2025 federal poverty line for a single individual.
The FPL safe harbor offers certainty because the threshold is a fixed dollar amount, but it can be expensive for employers with low-wage workers — you may end up subsidizing coverage more heavily than the W-2 or rate-of-pay tests would require.
Rate of Pay safe harbor
For hourly workers, take the lowest hourly rate × 130 hours × 9.96 percent. That's the maximum monthly employee contribution.
For salaried workers, take the monthly salary × 9.96 percent.
This works well for employers with predictable wages but breaks down for tipped industries and commission-heavy roles where actual take-home varies wildly month to month.
W-2 Box 1 safe harbor
Coverage is affordable if the employee's share of the premium does not exceed 9.96 percent of their Box 1 wages on Form W-2 for the year. This is computed retrospectively, so you only know whether you cleared the safe harbor after the year ends.
The W-2 method works for stable-wage employees but penalizes employers when workers take unpaid leave, leave mid-year, or have pre-tax deductions that drop Box 1 below their actual cash earnings.
Minimum value: the 60 percent test
Affordability is only half of the B penalty defense. The coverage you offer also has to provide minimum value, meaning the plan covers at least 60 percent of the total allowed cost of benefits and provides substantial coverage for inpatient hospital and physician services.
Most fully-insured small-group plans clear the 60-percent test out of the box. Self-funded plans and bare-bones HSA-paired plans sometimes don't. If your plan is on the edge, get an actuarial opinion before you build your 1095-C codes around it.
Form 1095-C: line by line
Once you've structured coverage that meets the 95-percent offer rule and is affordable, the 1095-C is how you prove it to the IRS. Each full-time employee receives one form, and the IRS reads the form mechanically — the Letter 226-J penalty assessments come straight from the code combinations you reported.
Line 14: the offer of coverage code (Series 1)
This is what was offered, regardless of whether the employee took it. The codes most employers use:
- 1A — Qualifying Offer: MEC providing minimum value to the employee at a cost of no more than 9.96 percent of the mainland single FPL, plus MEC offered to spouse and dependents. Triggers an automatic affordability conclusion, which means you can leave Line 15 blank.
- 1E — MEC providing minimum value to employee, plus MEC to spouse and dependents. The workhorse code for employers offering family coverage.
- 1H — No offer of coverage. Used for months an employee was not eligible or not full-time.
Picking 1A when you really should have used 1E is a common error. 1A requires that the employee contribution stays under the FPL safe harbor every month; if even one month exceeds $129.89, the 1A code is wrong and the IRS may assess the B penalty when matching against the marketplace data.
Line 15: employee required contribution
This is the lowest monthly cost for self-only coverage providing minimum value. Required only if Line 14 has 1B, 1C, 1D, 1E, 1J, 1K, 1L, 1M, 1N, 1O, 1P, or 1Q. If you reported 1A or 1H, leave Line 15 blank for that month.
Omitting Line 15 when it is required is one of the top three reasons for IRS error notices.
Line 16: safe harbor and other relief (Series 2)
This is where most penalty assessments quietly originate. Series 2 codes tell the IRS why no penalty should apply for that month:
- 2A — Employee not employed any day of the month.
- 2B — Employee not full-time and did not enroll.
- 2C — Employee enrolled in coverage offered. Strongest possible code; blocks both A and B penalties for that month.
- 2D — Employee in a Section 4980H(b) Limited Non-Assessment Period (initial measurement period, waiting period, etc.).
- 2F — W-2 safe harbor used for the year.
- 2G — FPL safe harbor used.
- 2H — Rate-of-pay safe harbor used.
When an employee declines coverage and you offered affordable coverage, the right answer on Line 16 is 2F, 2G, or 2H — whichever safe harbor you actually applied. Leaving Line 16 blank in that scenario is what causes the IRS to issue a Letter 226-J proposing a B penalty.
Filing deadlines and the new electronic filing rules
For the 2025 calendar year (the next reporting cycle you're working through right now in 2026):
- Furnish employee copies: by March 3, 2026 (the original January 31 deadline plus the 30-day automatic extension that became permanent in 2024).
- Paper filing with the IRS: by February 28, 2026. Almost no one is eligible for paper filing anymore — the threshold dropped to 10 aggregate information returns in 2024.
- Electronic filing with the IRS: by March 31, 2026.
Late filing penalties for 2026 are $340 per return with an annual cap of $4,098,500. Intentional disregard removes the cap entirely. Penalties accumulate per copy — a single botched 1095-C can cost you $340 for the IRS copy and another $340 for the employee copy.
Two recent compliance relief items worth knowing
Two provisions enacted in 2024 changed the day-to-day reality of 1095-C reporting:
- Alternative furnishing method: Employers may now satisfy the requirement to provide a 1095-C to employees by posting a clear and conspicuous notice on their website stating that any employee may request a copy. This eliminates the mass-mailing burden for many ALEs, though you still must furnish a copy within 30 days of any individual request.
- Six-year statute of limitations on assessments: Letter 226-J penalty assessments now have a firm six-year clock starting from the original return's due date. Before this change, the IRS argued there was no statute of limitations at all on ESRP assessments.
The mistakes that quietly drive Letter 226-J assessments
The IRS doesn't audit 1095-C compliance in the traditional sense. Instead, it cross-matches your 1095-C codes against marketplace subsidy data and mails Letter 226-J the moment its software detects a gap. The proposed penalties are mechanical — they reflect what your codes told the IRS, not what actually happened.
Recurring patterns that drive false assessments:
- Reporting intended coverage instead of actual coverage. The 1095-C must reflect what was actually offered and available, not what HR meant to offer. If a new-hire orientation packet was never delivered, the offer was not made.
- Blank Line 16 when an employee declines coverage. Without a Series 2 code, the IRS assumes the offer was unaffordable. Always document which safe harbor applied.
- Mismatch between 1094-C totals and 1095-C counts. The transmittal totals must reconcile to the individual forms; a single off-by-one error triggers a CP-225 notice.
- Wrong dependent definition. For 1095-C purposes, "dependent" means biological or adopted children under 26. Spouses are not dependents. Failing to offer coverage to children of full-time employees is the most common A-penalty trigger for otherwise compliant employers.
- Using 1A without checking actual contribution amounts. The 1A code includes a built-in affordability assertion at FPL levels. If you raised the employee contribution mid-year above $129.89, the 1A is no longer accurate.
- Ignoring the look-back measurement period. Variable-hour employees become full-time based on the measurement period. Treating them as part-time during the stability period — when the look-back tagged them as full-time — creates both an offer failure and a coding failure.
If you do receive a Letter 226-J, respond on Form 14764 within 30 days. The IRS routinely reduces or eliminates assessments when employers document the actual offer, contribution, and safe harbor used. Failing to respond locks in the proposed penalty.
Keep clean records before the IRS asks
The most expensive ACA penalties are the ones employers discover three years late, after the original benefits administrator has left and the source documentation has been archived. Maintaining a clear, plain-text audit trail of every coverage offer, every employee contribution rate, and every safe harbor decision turns a Letter 226-J response from a forensic project into a five-minute lookup.
Beancount.io provides plain-text accounting that records every payroll and benefits transaction in version-controlled, human-readable files — no proprietary database, no vendor lock-in, no waiting for a former payroll provider to export your history. Get started for free and keep the records you'll need long after this reporting year is closed.