ACA Forms 1094-C and 1095-C: The 2026 Compliance Playbook for Applicable Large Employers

Hire your 50th full-time employee in 2025, and a quiet thing happens to your company in 2026: you become a federally regulated health benefits reporter, with March deadlines, six-figure penalty exposure, and a six-year IRS lookback window that didn't exist a few years ago. Most CFOs and HR leads know the Affordable Care Act's employer mandate by reputation, but the actual reporting machinery — Forms 1094-C and 1095-C, the Section 6056 framework, the new "furnish on request" rules from the 2024 reforms — trips up even seasoned payroll teams every January.

This year the rules are friendlier in some places and tougher in others. Penalty amounts went up. The 90-day response window finally gives employers room to fight back against IRS Letter 226-J assessments. And the requirement to mail every employee a paper Form 1095-C is, for most employers, dead. Here's how to handle the 2025 reporting year (filed in early 2026) without leaving money on the table.

What These Forms Actually Are

The ACA created two reporting regimes that often get confused:

• Section 6055 asks the entity providing minimum essential coverage (insurers, government programs, and self-insured employers) to report which individuals were covered.
• Section 6056 asks Applicable Large Employers (ALEs) to report whether they offered coverage to each full-time employee, what that coverage cost, and whether it satisfied the affordability and minimum value tests.

If you're an ALE with fully insured coverage, your carrier handles 6055 on Form 1095-B; you handle 6056 on Form 1095-C. If you're an ALE with a self-insured plan, you do both on Form 1095-C using Part III. Either way, you also file a transmittal summary on Form 1094-C and certify, under penalty of perjury, that you offered affordable, minimum-value coverage in line with the employer mandate.

The IRS uses these forms in two ways: to assess Section 4980H "pay-or-play" penalties on employers, and to verify whether individuals were eligible for premium tax credits on the exchanges. Both audits start with what's printed on your 1095-Cs.

Are You Actually an ALE? The 50-FTE Test

Status as an ALE for 2026 depends on your headcount during the 2025 calendar year. The test has three moving parts:

Full-time employees. Anyone averaging 30 or more hours per week, or 130 hours per calendar month, in a given month.

Full-time equivalents. Sum up the monthly hours worked by part-timers (cap each at 120 hours), then divide by 120. Ten part-timers each working 60 hours per month equals 5 FTEs.

Average across the year. Add each month's full-time count plus that month's FTE figure, and divide by 12. If the answer is 50 or more, you're an ALE next year.

The most common surprise: aggregated groups. If you control multiple entities (parent-subsidiary chains, brother-sister groups with common ownership, or affiliated service groups under §414), you add headcount across all of them. A 30-person agency and a 25-person side venture under the same owners can collectively trip the ALE threshold even though neither does alone. The mandate's "shared responsibility" penalties also get allocated across the group.

The seasonal worker exception. If your workforce exceeds 50 employees only because of seasonal hires, and those seasonal employees are above the 50 threshold for 120 days or fewer (not necessarily consecutive) during the year, you can exclude them from the ALE calculation. Retail at Christmas, ski resorts in winter, agriculture at harvest — these are textbook examples. Note that the IRS uses "seasonal worker" specifically here, distinct from the broader "seasonal employee" concept used elsewhere in the ACA.

The 2026 Deadlines, Crystallized

For the 2025 reporting year, three dates matter:

Action	Deadline
Furnish 1095-C to employees (or post availability notice)	March 2, 2026
File Forms 1094-C/1095-C by paper (very limited eligibility)	March 2, 2026
File Forms 1094-C/1095-C electronically	March 31, 2026

Note that the statutory furnishing deadline is January 31, but the IRS regulations build in an automatic 30-day extension. February 28 falls on a Saturday in 2026, so the paper deadline moves to Monday, March 2.

Electronic filing is now nearly universal. Any employer filing 10 or more total information returns of any kind during the calendar year must file electronically. That aggregate count combines W-2s, 1099s, 1094s, 1095s, and other information returns — meaning even small ALEs (50–99 employees) effectively must e-file through the IRS AIR (Affordable Care Act Information Returns) system or a vendor that submits on their behalf.

The IRS only grants automatic 30-day filing extensions if you submit Form 8809 before the deadline. Furnishing extensions to employees require a written justification and aren't guaranteed.

What Changed in 2024–2025: The Two Reform Acts

In December 2024, two pieces of legislation quietly rewrote the operational rules: the Paperwork Burden Reduction Act and the Employer Reporting Improvement Act. The IRS confirmed in 2025 guidance that these changes apply to the 2024 reporting year and forward, so the 2025 returns you file in 2026 fully reflect them.

Furnishing on Request, Not by Default

ALEs no longer have to automatically mail every full-time employee a Form 1095-C. Instead, you satisfy the furnishing requirement by:

1. Posting a "clear, conspicuous, and accessible" notice — typically on your benefits or HR intranet, or on the public-facing company site — informing employees they can request a copy.
2. Providing a copy when requested, by the later of January 31 of the following year or 30 days after the request.

The IRS hasn't prescribed exact notice language, but most counsel recommend clear, plain-English wording, a working email or web form for requests, and a year-round availability commitment. Don't bury the notice on page 40 of an open-enrollment PDF.

A few states still require automatic furnishing under their own individual mandates (California, New Jersey, Rhode Island, the District of Columbia, and Massachusetts). If you have employees in those jurisdictions, you may still need to mail forms regardless of the federal relief.

Electronic Furnishing by Consent

You can also furnish electronically if the employee consents — preferred for distributed and remote workforces. The consent must be obtained electronically in a way that reasonably demonstrates the employee can access the form in the electronic format, and you must disclose the hardware/software requirements and right to withdraw consent.

Substitute TINs for Dependents

For self-insured plans reporting covered individuals in Part III of Form 1095-C, if you can't obtain a dependent's TIN or SSN after reasonable efforts, you can now report full legal name and date of birth instead. Document the outreach you made (typically two written requests).

90-Day Response to Letter 226-J

The Letter 226-J is the IRS's opening shot when it believes you owe a Section 4980H penalty. Historically, employers had 30 days to respond with Form 14764 disputing the assessment. The 2024 reform extends that window to 90 days. Calendar this carefully: missing the response deadline turns a proposed penalty into a final assessment, and contesting it from there is much harder.

Six-Year Statute of Limitations

Penalties under Section 4980H now have a six-year statute of limitations starting with returns due after December 31, 2024. Previously there was no defined limit, leading to assessments years after the fact. Preserve your reporting records — payroll histories, offer-of-coverage documentation, affordability calculations — for at least seven years.

The Penalty Stack You're Trying to Avoid

Two penalty regimes apply, and they can stack.

Reporting penalties (Sections 6721 and 6722). These hit you for filing late, filing on paper when you should have e-filed, or filing with incorrect or incomplete information. The 2026 schedule:

• $60 per return if corrected within 30 days
• $130 per return if corrected by August 1
• $340 per return if not corrected, or intentional disregard
• For 1095-C, both the IRS-filed copy and the employee-furnished copy count — so each error can trigger two penalties, capped at over $4 million per year for non-small employers

Employer mandate penalties (Section 4980H), 2026 amounts:

• §4980H(a) "sledgehammer" penalty: $3,340 per year per full-time employee (less the first 30), triggered if you fail to offer minimum essential coverage to at least 95% of full-time employees and at least one of them gets a premium tax credit on the exchange.
• §4980H(b) "tackhammer" penalty: $5,010 per year per full-time employee who actually receives a premium tax credit because your offer was unaffordable or didn't meet minimum value.

For an employer with 200 full-time employees, missing the 95% threshold for a full year exposes you to $568,000+ in (a) penalties — and that's separate from any reporting penalty stack.

The affordability safe harbor for 2026 plan years requires the employee's self-only contribution to be no more than 9.96% of household income, with three IRS-blessed proxies for household income (W-2 wages, rate of pay, or federal poverty line). Most employers use the federal poverty line safe harbor for simplicity.

The Codes That Drive Everything

Form 1095-C is largely a coded form. Two boxes on each employee's form do the heavy lifting:

Line 14: Offer of Coverage. Two-character codes describing what you offered, to whom, and starting when. Common ones:

• 1A — Qualifying Offer (affordable per federal poverty line, minimum value, to employee + spouse + dependents)
• 1E — Minimum essential coverage offering minimum value to employee, plus at least minimum essential coverage to spouse and dependents
• 1H — No offer of coverage in the month
• 1G — Self-insured coverage offered to a non-employee (e.g., COBRA participant, retiree)

Line 16: Section 4980H Safe Harbor and Other Relief. This is where you tell the IRS why you shouldn't be penalized for a month with no offer. Examples:

• 2A — Not employed any day in the month
• 2C — Employee enrolled in coverage
• 2D — Limited non-assessment period (waiting period, initial measurement period)
• 2F/2G/2H — Affordability safe harbor: W-2 wages / federal poverty line / rate of pay

The interplay between Line 14 and Line 16 is what determines whether the IRS algorithm thinks you owe a penalty for that employee-month. Single-coding errors — a 2C where it should be 2A, a 1H where you actually made an offer — are the most common source of phantom 4980H assessments. Build a code-checking step into your year-end review and reconcile Line 14/16 patterns against your payroll system before submitting.

Common Mistakes That Trigger Audits

After a decade of ACA enforcement, the IRS has gotten methodical. Here are the failures that most reliably attract Letter 226-J:

Counting wrong on the ALE test. Forgetting to include FTEs, missing the aggregation rules for commonly controlled entities, or excluding interns and seasonal hires incorrectly.

Mixing up the look-back measurement method and the monthly measurement method. Most employers use a 12-month look-back measurement period with a 90-day administrative period and a 12-month stability period. Switching methods mid-year, or applying the wrong method to a class of employees, creates gaps the IRS will spot.

Wrong cost of coverage on Line 15. This is the employee's required monthly contribution for the lowest-cost self-only minimum-value plan. Many employers put the cost of family coverage here, or the cost of the most popular plan, or the employer's contribution. None of those is right.

Missing or incorrect ICHRA codes. If you offer an Individual Coverage HRA, there's a dedicated set of codes (1L–1S) and an affordability calculation tied to the lowest-cost silver plan in the employee's rating area. Most off-the-shelf payroll systems still get this wrong.

Ignoring the employer's identifying number. Each ALE Member files separately, even within an aggregated group. The Authoritative Transmittal box on Form 1094-C must be checked exactly once per ALE Member.

Submitting on paper when you have 10+ returns. This is now a §6721 violation in itself, separate from any content errors.

A Sane Annual Workflow

For a mid-sized employer (say 100–500 employees), the practical reporting calendar looks like this:

October–November (prior year): Reconcile the prior year's payroll to determine ALE status for the upcoming reporting year. Lock down the measurement method and any class definitions. Decide whether to use a vendor or self-file through AIR.

December: Distribute the open-enrollment package and capture coverage elections. Update your benefits administration system with all 2026 plan year cost data.

Each month of the reporting year: Generate monthly offer-of-coverage and enrollment data from your benefits system. Reconcile new hires, terminations, COBRA elections, and leaves of absence — these are the events most likely to produce coding errors at year-end.

January (following year): Run a draft of all 1095-Cs. Audit Line 14/16 combinations using IRS-published rules. Reconcile total offer counts against payroll headcount. Validate the §4980H affordability calculation for at least the lowest-paid full-time employees in each class.

By March 2: Either mail 1095-Cs or post the availability notice. Begin responding to employee requests.

By March 31: Submit Forms 1094-C and 1095-C through AIR. Save the IRS acknowledgement files. The IRS sometimes returns errors after submission — fix and resubmit within 60 days to avoid a reporting penalty.

When a Letter 226-J Arrives

If your reporting was clean, you may still receive one. The IRS uses an algorithm that flags any employer where one or more full-time employees received a premium tax credit on the exchange. Often the assessment is wrong on the facts — the employee got a PTC despite an affordable offer, or wasn't actually a full-time employee in the relevant months.

Respond on Form 14764, attach corrected documentation, and use the new 90-day window. Common winning responses include:

• Showing the employee was not full-time in the disputed months (with timesheet evidence)
• Proving the offer was actually affordable under the safe harbor used
• Demonstrating the employee was in a limited non-assessment period
• Correcting a Line 14/16 coding error on the original 1095-C

Don't ignore Letter 226-J. Even with the longer response window, the IRS won't extend it again, and unresponded letters convert to final assessments that escalate through normal IRS collection channels.

Where Bookkeeping Habits Pay Off

The 1094-C/1095-C reporting cycle is fundamentally a data-reconciliation exercise: payroll hours, benefits enrollment events, COBRA elections, and dependent rosters all need to agree before the forms make sense. Employers that maintain clean monthly close processes — with payroll reconciled to GL, benefits expense tied to vendor invoices, and an audit trail back to source documents — file ACA reporting in days. Employers that don't, spend February in spreadsheets trying to figure out why their 1095-C output doesn't match their payroll run.

The same discipline that produces a credible Form 1094-C produces a credible 401(k) testing file, a credible workers' comp audit, and a credible W-2 reconciliation. If your year-end is a fire drill, the fix is upstream of any single form.

Keep Your Financial Records Audit-Ready

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