ACA reporting has its own vocabulary. And the terms aren't interchangeable, even when they sound like they could be. An ALE isn't the same as a controlled group. MEC isn't the same as Minimum Value. Safe harbors don't cover you unless you pick the right one for the right employee. Small distinctions, but they're the ones that decide whether your reporting holds up or generates a Letter 226J.
Use this as a working reference. The terms are grouped the way they come up in the reporting cycle: who has to report, what coverage counts, who's considered full-time, how you track them, what you file, and what happens when something's off. A short FAQ at the bottom covers the questions that come up most.
On this page
- The Framework: Who Has to Report
- Coverage & Affordability
- Employee Classification
- Measurement Methods
- The Forms
- Filing & Corrections
- Penalties & Enforcement
- FAQ
The Framework: Who Has to Report
- ACA reporting
- ACA reporting: The annual process of filing forms with the IRS (and furnishing them to employees) to show what health coverage you offered during the year. For most employers, that means Forms 1094-C and 1095-C. Full Guide
- Employer mandate
- The Affordable Care Act provision requiring larger employers to offer affordable, minimum essential coverage (MEC), and minimum value(MV) health coverage to full-time employees, or potentially face a penalty. Full Guide
- Applicable Large Employer (ALE)
- An employer with 50 or more full-time employees (including full-time equivalents) in the prior calendar year. If you're an ALE, the employer mandate and 1094-C/1095-C reporting apply to you. Full Guide
- Full-time equivalent (FTE)
- A calculated number that converts part-time hours into "equivalent" full-time employees for the purpose of the ALE threshold. You add up all the hours worked by part-time/variable hour employees in a month (maximum of 120 per employee), divide by 120, and add that to your full-time headcount. Part-timers don't have to be offered coverage under the employer mandate, but they count toward whether you cross the 50-employee line.
- Controlled group / aggregation rules
- Separate legal entities that share common ownership are treated as one employer for ALE purposes. So a parent company with five subsidiaries doesn't get to look at each one's headcount in isolation. All employees across the group get aggregated, and if the combined total hits 50 FTE, everyone in the group is an ALE. Full Guide
Coverage & Affordability
- Minimum Essential Coverage (MEC)
- The baseline test for whether a health plan qualifies as coverage under the ACA. Most employer-sponsored group plans meet MEC by default, but skinnier arrangements (like fixed-indemnity plans or discount cards) usually don't. If what you're offering isn't MEC, it doesn't count as an offer of coverage for employer mandate purposes.
- Minimum Value
- A plan provides Minimum Value if it covers at least 60% of the total allowed cost of benefits and includes substantial coverage of inpatient hospital and physician services. Full Guide
- ACA affordability
- Coverage is "affordable" if the employee's cost for the lowest-priced self-only plan doesn't exceed a set percentage of their income. The percentage is adjusted annually by the IRS. Affordability is measured per employee, not across the workforce as a whole. Full Guide
- Rate of Pay safe harbor
- One of three IRS-approved shortcuts for proving affordability. You calculate affordability based on the employee's hourly rate multiplied by 130 hours per month. Easiest to use for hourly workers with predictable schedules. More on safe harbors
- W-2 safe harbor
- Bases affordability on the employee's W-2 Box 1 wages for the year. Useful for salaried workers, but it's a look-back calculation, so you don't fully know if you passed until the year is over. More on safe harbors
- Federal Poverty Line (FPL) safe harbor
- Allows employers to prove the plan is affordable by showing that the lowest-cost plan for employee-only coverage does not exceed the affordability percentage of the Federal Poverty Line. (Published by HHS each year) More on safe harbors
Employee Classifications
- Full-time employee (ACA definition)
- An employee who averages at least 30 hours of service per week (or 130 hours per month). Note this is the ACA's definition, not your company's. Someone your HR system labels "part-time" may still be full-time for ACA purposes. Full Guide
- Variable-hour employee
- An employee whose hours are expected to fluctuate enough that you can't reasonably determine at hire whether they'll average 30 hours per week. This classification is what lets you use the look-back measurement method instead of having to decide on their status right away. Full Guide
- Seasonal employee
- An employee hired into a position that's customary for six months or fewer and generally starts at roughly the same time each year (think retail holiday hires, agricultural workers, ski resort staff). Seasonal employees can be excluded from the full-time count in specific situations, and they get their own treatment under the measurement method rules. "seasonal employee" (ACA) and "seasonal worker" (used in the ALE calculation) are different terms with different rules.
- New hire vs ongoing employee
- The distinction that determines which measurement method applies. An ongoing employee is one who's worked for you through at least one full standard measurement period. A new hire hasn't yet. New hires use an initial measurement period tied to their start date; ongoing employees use the standard measurement period that applies to the whole workforce. Which bucket someone falls into affects when they need to be offered coverage.
Measurement Methods
- Measurement period
- A stretch of time (typically 3 to 12 months) where you track an employee's hours to figure out whether they qualify as full-time for ACA coverage purposes. It's the mechanism that answers the practical question "who do I have to offer coverage to?" for workforces where hours aren't predictable. Full Guide
- Administrative period
- The optional buffer between the end of a measurement period and the start of the stability period, up to 90 days. It's the window for identifying who qualified as full-time, notifying them, and getting them enrolled. Skipping it or shortchanging it is one of the more common ways benefits administrators end up in a scramble.
- Stability period
- The stretch of time typically after the Admin Period, where an employee's status (full-time or not) is locked in based on what you measured. If they qualified as full-time during measurement, they get offered coverage throughout the stability period, even if their hours drop. Full Guide
- Look-back measurement method
- One of the two IRS-approved methods for determining full-time status. You look back over a set measurement period, average the employee's hours, and use that to decide their status for the following stability period. Best for workforces with fluctuating hours (retail, hospitality, staffing). Full Guide
- Monthly measurement method
- An IRS-approved method for determining full-time status. Instead of looking back over a longer window, you determine full-time status on a month-by-month basis. An employee who crosses 130 hours in a given month is full-time for that month and typically needs an offer of coverage immediately. Works well for stable, predictable workforces; poorly for variable ones.
The Forms
- Form 1095-C
- The employee-level form. One per full-time employee, per year, showing what coverage was offered each month, what the employee's share of the premium would have been, and whether they enrolled. Employees get a copy; the IRS gets a copy. Full Guide
- Form 1094-C
- The employer-level transmittal form. Think of it as the cover sheet that goes with your batch of 1095-Cs. It reports aggregate information about your organization: whether you're part of a controlled group, your total full-time employee count by month, and whether you offered coverage to at least 95% of full-time employees. You file one 1094-C per employer, regardless of how many 1095-Cs it's transmitting.
- 1094-C vs 1095-C
- 1095-C is one-per-employee, 1094-C is one-per-employer. If you have 400 full-time employees, you file 400 Forms 1095-C and one Form 1094-C to cover them all.
- 1095-C Line 14 codes
- A two-character code entered for each month, describing what kind of coverage (if any) was offered to that employee. The codes distinguish offers to the employee alone, to the employee plus spouse, to the employee plus family, and various individual coverage HRA scenarios. Full Guide
- 1095-C Line 16 codes
- A two-character code entered for each month, explaining the employee's status in a way that either establishes safe harbor protection or explains why no offer was made. Full Guide
Filing & Corrections
- ACA reporting deadlines
- The IRS sets annual deadlines for both furnishing 1095-Cs to employees and filing the 1094-C/1095-C set with the IRS. Furnishing deadlines are earlier than filing deadlines, and electronic filing deadlines are later than paper. Miss either one without an extension and penalties accrue per form, per day. Full Guide
- Corrected 1095-C
- A 1095-C you file to fix an error on one you already submitted. The IRS has a specific process (mark the "CORRECTED" box, re-file the whole form, re-furnish to the employee). Full Guide
- Furnishing vs filing
- Two separate obligations that happen at different times to different audiences. Furnishing means providing or making available a copy of each employee's 1095-C form. Filing means transmitting the forms to the IRS. You are required to do both. Full Guide
- AIR (Affordable Care Act Information Returns) system
- The IRS's electronic filing system for ACA forms. Any ALE filing 10 or more returns has to file electronically through AIR (or a service provider that transmits through it). It's not a form; it's the pipe your forms travel through.
- Transmitter Control Code (TCC)
- A five-character ID the IRS issues to organizations that want to file ACA returns electronically through AIR. Applying for a TCC takes weeks and requires going through the IRS's e-Services setup, which is why most employers file through a reporting service that already has one.
Penalties & Enforcement
- Employer Shared Responsibility Payment (ESRP)
- The IRS's umbrella term for the two types of employer mandate penalties (4980H(a) and 4980H(b)). If the IRS thinks you owe one, they will send a Letter 226J. ESRP is also used for the employer shared responsibility provisions, which covers the ACA compliance rules and penalties for employers. Full Guide
- 4980H(a) penalty ("sledgehammer")
- Triggered when an ALE fails to offer minimum essential coverage to at least 95% of its full-time employees for a month, and at least one full-time employee receives a premium tax credit through the marketplace. The penalty is calculated on your entire full-time workforce (minus 30), not just the employees who weren't offered coverage. One person missed can put every full-time employee on the invoice.
- 4980H(b) penalty ("tack hammer")
- Triggered when an ALE does offer coverage but that coverage is either unaffordable or doesn't provide Minimum Value, and an affected employee receives a premium tax credit through the marketplace. Unlike the (a) penalty, this one is calculated per affected employee, not workforce-wide. Smaller per instance, but it can accumulate quickly across a lot of employees with borderline-affordable offers.
- Letter 5699
- If the IRS believes a company should have filed 1094/1095 forms, it will send Letter 5699, missing information return, as the preliminary notice for the company.
- Letter 226J
- The IRS's proposed-penalty notice for employer mandate violations. It arrives with a specific amount, a form to respond, and a fairly tight deadline. It's not a bill; it's the opening move in a back-and-forth where you can dispute the calculation. Ignoring it turns the proposed penalty into an actual one. Full Guide
Frequently Asked Questions
MEC (Minimum Essential Coverage) is the baseline test for whether a plan qualifies as coverage at all. Minimum Value is the higher bar: the plan has to cover at least 60% of the total cost of benefits and include substantial hospital and physician coverage. To satisfy the employer mandate, coverage has to meet both. MEC alone isn't enough.
Add up all the hours worked in a month by employees who work fewer than 30 hours per week, divide by 120, and add that number to your full-time headcount for the month. Do this for each month of the prior year, then average the 12 monthly totals. If the average is 50 or more, you're an ALE for the current year. Remember that part-time hours count toward the threshold, even though part-timers don't have to be offered coverage.
The look-back method averages an employee's hours over a longer measurement period (typically 6 to 12 months) and locks in their status for a matching stability period. The monthly method looks at hours one month at a time and determines status on a rolling basis. Look-back is more forgiving for variable-hour workforces; monthly is simpler but requires faster reaction when hours cross 130 in a month.
The (a) penalty ("sledgehammer") applies when you failed to offer coverage to at least 95% of full-time employees. It's calculated on your entire full-time workforce minus 30. The (b) penalty ("tack hammer") applies when you did offer coverage but it was unaffordable or lacked Minimum Value. It's calculated per affected employee. You can only owe one or the other for a given month, not both.
1095-C is the employee-level form: one per full-time employee, showing what coverage was offered each month. 1094-C is the employer-level transmittal: one per employer, summarizing your organization's ACA reporting for the year and accompanying the batch of 1095-Cs. Simplest way to remember: 1095 = one per person, 1094 = one per company.
The letter proposes a penalty amount based on the IRS's read of your filed 1094-C/1095-C data, along with a response form and a deadline (usually 30 days). You can agree, or you can respond disputing the calculation by explaining errors, documenting offers of coverage, or providing corrected data. If you don't respond, the proposed penalty becomes final.
You don't need to memorize all of this. You just need to recognize the terms and know which decisions the whole reporting process comes back to: are you an ALE, what coverage did you offer, who counted as full-time, and did you file on time. Most ACA trouble traces back to a wrong answer on one of those four.
Getting them right on every employee, every month, and every form is exactly the kind of work software is built for. If that sounds like time you'd rather get back, we'd love to show you how Points North handles it. Explore ACA Reporter by Points North.
