The Affordable Care Act has been law for well over a decade, yet ACA compliance still trips up business owners every filing season. Missed deadlines, miscalculated affordability thresholds, and incomplete Forms 1095-C can trigger IRS penalty notices that run into the tens of thousands of dollars — often for errors that were entirely avoidable. If your company is approaching 50 full-time equivalent employees, or if you already clear that threshold, understanding your ACA employer reporting obligations is not optional. It is one of the most consequential compliance responsibilities your business carries.

Who Must Comply: The Applicable Large Employer Definition

The ACA employer mandate applies to Applicable Large Employers (ALEs) — organizations that employed an average of at least 50 full-time equivalent (FTE) employees during the prior calendar year. Reaching that count triggers two overlapping obligations: the employer shared responsibility provision (also called the pay-or-play rule) and the annual ACA information reporting requirement.

Calculating FTE status is where many employers stumble. Full-time employees work 30 or more hours per week. Part-time hours are aggregated — divide total monthly part-time hours by 120 to arrive at your FTE count for that month, then average across all 12 months. Seasonal workers, variable-hour employees, and employees of related entities under common ownership all factor into this calculation. A single miscalculation can shift your classification and either create unexpected obligations or give you false confidence that you are exempt.

The Pay-or-Play Rule: Minimum Essential Coverage and Affordability

Once you are classified as an ALE, you must offer minimum essential coverage (MEC) to at least 95 percent of your full-time employees and their dependents, and that coverage must meet two additional tests:

  • Minimum value: The plan must pay at least 60 percent of the total allowed cost of benefits.
  • Affordability: The employee's required contribution for self-only coverage cannot exceed a specified percentage of their household income. For 2025, the IRS affordability threshold is 9.02 percent of household income — though most employers use one of the IRS-approved safe harbor methods tied to W-2 wages, the federal poverty line, or the employee's rate of pay.

Failing either test — or failing to offer coverage at all — exposes your business to Employer Shared Responsibility Payments under IRC Section 4980H. Section 4980H(a) penalties apply when no coverage is offered; Section 4980H(b) penalties apply when coverage is offered but is unaffordable or does not provide minimum value. Both penalty amounts are adjusted annually and can accumulate quickly across a large workforce.

ACA Employer Reporting: Forms 1094-C and 1095-C

Every ALE must file an annual information return with the IRS and furnish statements to employees. Specifically:

  1. Form 1095-C must be provided to each full-time employee, documenting the coverage offered, the employee's share of the lowest-cost premium, and enrollment details for each month of the calendar year.
  2. Form 1094-C is the transmittal form that accompanies your 1095-C package to the IRS, summarizing your organization's offer-of-coverage data across all employees.

The employee furnishing deadline is generally March 3 of the following year. Electronic filing with the IRS is now mandatory for employers submitting 10 or more returns in aggregate — a threshold significantly tightened by the Taxpayer First Act. Paper filers subject to the electronic mandate face separate penalties. Accuracy matters as much as timeliness: errors in Employee Plan Codes, safe harbor codes, or Social Security Numbers are common triggers for IRS penalty letters known as Letter 226-J.

Common ACA Compliance Pitfalls to Avoid

Even well-intentioned employers make costly mistakes. Watch out for these recurring issues:

  • Failing to track hours for variable-hour or seasonal employees during required measurement periods
  • Using the wrong affordability safe harbor or failing to update thresholds each plan year
  • Mismatching plan codes on 1095-C forms, especially when multiple benefit plan options are available
  • Missing the distinction between self-insured and fully insured plans, which affects which lines of Form 1095-C must be completed
  • Overlooking ACA obligations after a merger, acquisition, or significant workforce expansion that crosses the 50-FTE threshold mid-year

Receiving a Letter 226-J does not automatically mean you owe the full proposed penalty. Employers have the right to respond and dispute the IRS's calculations — but the response window is tight, typically 30 days, so having organized records is essential.

How Outsourced HR and Benefits Administration Simplifies ACA Reporting

Managing ACA compliance in-house demands precise data from payroll, benefits, and HR systems working in concert. Hours data must flow accurately into FTE calculations. Benefit election records must align with what appears on each 1095-C. Deadlines must be tracked across a calendar already crowded with W-2s, 401(k) reporting, and state filings.

An Administrative Services Organization like Nomad Partners integrates payroll administration, employee benefits management, and HR administration into a single coordinated service. That means your hours data, coverage elections, and employee records are maintained in one place — reducing the transcription errors and data gaps that cause ACA reporting problems. Our team monitors threshold changes, affordability updates, and filing deadlines so nothing slips through the cracks.

ACA compliance is not a once-a-year task. It is a year-round data management discipline that requires your payroll and benefits records to stay synchronized every single month.

If your organization is navigating ACA employer reporting obligations for the first time, approaching the 50-FTE threshold, or simply tired of managing the complexity internally, connect with Nomad Partners today. We will walk you through exactly where your compliance gaps are and show you how integrated HR administration can protect your business from preventable penalties.