The Affordable Care Act has been law since 2010, yet ACA compliance still catches employers off guard every single year. Missed deadlines, incorrect forms, and misunderstood coverage rules lead to IRS penalty notices that can cost tens of thousands of dollars — sometimes more. If you sponsor employee health coverage or are approaching 50 full-time equivalent employees, understanding your ACA reporting obligations is not optional. This guide breaks down exactly what you owe, when you owe it, and how to stay on the right side of the IRS.

Who Is Subject to ACA Employer Mandate Requirements?

The ACA's employer shared responsibility provisions apply to Applicable Large Employers (ALEs) — organizations that employed an average of at least 50 full-time equivalent (FTE) employees during the prior calendar year. Calculating your FTE count sounds simple, but it includes part-time hours converted to full-time equivalents, which means a business with 35 full-time workers and a large part-time workforce can easily qualify as an ALE without realizing it.

ALEs must offer minimum essential coverage (MEC) to at least 95% of their full-time employees and their dependents up to age 26. That coverage must also meet minimum value standards — meaning it pays at least 60% of the cost of covered services — and must be affordable based on IRS affordability thresholds, which adjust annually. For 2024, the affordability percentage is 8.39% of an employee's household income. Because employers rarely know household income, the IRS provides three safe harbors: W-2 wages, rate of pay, and the federal poverty line.

Employers under 50 FTEs are not subject to the employer mandate, but if they offer health coverage they may still have reporting obligations depending on the plan structure.

ACA Reporting Forms: 1094-C, 1095-C, and 1095-B Explained

ACA employer reporting centers on two primary IRS forms that ALEs must file annually:

  • Form 1095-C — Furnished to each full-time employee. It reports whether coverage was offered, the employee's share of the lowest-cost monthly premium, and whether the employee enrolled. This is the employee's proof of coverage for their own tax return.
  • Form 1094-C — The transmittal form filed with the IRS summarizing all 1095-C forms submitted. It also includes information about your ALE status and whether you qualify for any transition relief.

Self-insured employers — those who fund their own health plans rather than purchasing fully insured coverage — must also complete Part III of Form 1095-C to report actual enrollment data for every covered individual, including dependents. Fully insured plans shift that enrollment reporting responsibility to the insurance carrier, who files Form 1095-B directly.

Getting these forms right requires accurate payroll data, benefits enrollment records, and month-by-month coverage tracking across your entire workforce — including new hires, terminations, and employees who waived coverage.

ACA Filing Deadlines and What Happens If You Miss Them

ACA filing deadlines follow a consistent annual schedule tied to the prior calendar year:

  1. January 31 — Deadline to furnish Form 1095-C to employees (the IRS has historically granted short extensions, but these are not guaranteed).
  2. February 28 — Deadline to paper-file Forms 1094-C and 1095-C with the IRS (for employers filing fewer than 10 returns, following new thresholds effective 2024).
  3. March 31 — Deadline for electronic filing with the IRS. Electronic filing is now mandatory for most employers under updated IRS regulations.

Penalties for late or incorrect ACA reporting are assessed under IRC Sections 6721 and 6722. As of 2024, penalties can reach $330 per return for late filing and an additional $330 per return for failure to furnish correct employee statements — meaning the same error doubles your exposure. For an employer with 200 employees, that's a potential $132,000 penalty for a single filing season. Intentional disregard removes the per-return cap entirely.

Common ACA Compliance Mistakes Employers Make

Even well-intentioned employers make costly errors. The most frequent ACA compliance problems include:

  • Miscounting FTEs and failing to identify ALE status before the mandate kicks in
  • Offering coverage that fails the affordability test, triggering Section 4980H(b) penalties
  • Tracking coverage offers and waivers inconsistently throughout the year, leading to inaccurate 1095-C coding
  • Missing the electronic filing requirement after crossing the 10-return threshold
  • Failing to update records for mid-year status changes — leaves of absence, rehires, or variable-hour employees crossing the full-time threshold

Each of these mistakes is preventable with the right systems and oversight in place. The challenge for most employers is that ACA compliance sits at the intersection of payroll, benefits administration, and HR data — three functions that are often managed in silos.

How Integrated HR and Benefits Administration Simplifies ACA Reporting

Accurate ACA reporting depends on clean, connected data. When payroll records, benefits enrollment, and employee status changes live in separate systems — or worse, in spreadsheets — errors multiply. An integrated approach that links hours tracking, coverage offers, and enrollment decisions in one workflow dramatically reduces the risk of penalty-triggering mistakes.

Many employers find that outsourcing ACA compliance and employer reporting to an experienced administrative services partner is the most reliable path. A dedicated ASO can manage FTE calculations, monitor affordability thresholds, generate and distribute 1095-C forms, and handle IRS transmittals on your behalf — so deadlines never sneak up on your team and filings go out correctly the first time.

ACA compliance is not a once-a-year task. It requires year-round data hygiene, monthly coverage tracking, and timely responses to IRS correspondence — all of which demand consistent attention.

Let Nomad Partners Handle Your ACA Compliance

At Nomad Partners, we manage ACA reporting obligations as part of our end-to-end HR and benefits administration services. From determining your ALE status and monitoring affordability safe harbors to generating, distributing, and e-filing your 1094-C and 1095-C forms, we keep your compliance on track so you can focus on running your business. Talk to our team today and find out how we make ACA compliance straightforward, accurate, and stress-free.