Who Is Covered by COBRA: Employer Size and Plan Type

COBRA continuation coverage does not apply universally to every employer or every health plan in the United States. Federal law establishes specific thresholds — based on employer size and plan type — that determine whether an employer is obligated to offer continuation coverage at all. Understanding these thresholds is foundational to determining eligibility for both employers administering plans and employees evaluating their post-separation options.

Definition and scope

The Consolidated Omnibus Budget Reconciliation Act of 1985 (COBRA), codified primarily at 29 U.S.C. §§ 1161–1168 under the Employee Retirement Income Security Act (ERISA), mandates continuation coverage for group health plans maintained by private-sector employers meeting a specific size threshold. The Internal Revenue Code provisions at 26 U.S.C. § 4980B parallel these requirements and govern the excise tax penalties for noncompliance.

The core size rule: an employer that maintained a group health plan and employed 20 or more employees on at least 50 percent of its typical business days during the prior calendar year is subject to federal COBRA (U.S. Department of Labor, COBRA Continuation Coverage). This is commonly called the "20-employee threshold." Employers below this threshold fall outside federal COBRA jurisdiction, though many states have enacted mini-COBRA laws that impose parallel obligations — a framework examined in detail at Mini-COBRA: State Laws for Small Employers.

The complete regulatory framework for these coverage rules is set out under the regulatory context for COBRA administration, which addresses ERISA Title I, the Internal Revenue Code, and the Public Health Service Act provisions that collectively govern group health plan continuation obligations.

How it works

Coverage under federal COBRA applies through a layered determination. An employer must first clear the size threshold, then the plan itself must qualify, and finally the individual seeking coverage must be a "qualified beneficiary" who has experienced a qualifying event.

Employer size determination — 4-step process:

  1. Count all employees — full-time and part-time — across all common law employees during each business day of the prior calendar year (DOL, COBRA FAQs).
  2. Calculate typical business days — identify the total number of days the employer was in business during the prior year.
  3. Apply the 50-percent test — if the employer had 20 or more employees on at least half of its typical business days in the prior year, the employer is covered for the entire current year.
  4. Aggregate related employers — for controlled groups and affiliated service groups under IRC §§ 414(b), (c), (m), and (o), employee counts are aggregated across the entire controlled group, not assessed at the subsidiary level alone.

Plan type qualification:

Not every employer-sponsored benefit plan is subject to COBRA. The statute covers group health plans — arrangements that provide medical care to employees or their dependents, including through insurance, reimbursement, or otherwise. Specifically included:

Plans explicitly excluded from COBRA:

Common scenarios

Scenario A — Small employer, no federal obligation: A private software firm employs 14 full-time employees throughout the prior calendar year. Federal COBRA does not apply. The employer may still be subject to state mini-COBRA statutes depending on the state in which the plan is issued or administered.

Scenario B — Employer crosses the 20-employee line mid-year: A retail company employed 18 employees for the first half of the prior year and 22 employees for the second half. The calculation must determine whether 20 or more employees existed on at least 50 percent of typical business days across the full prior year — not just the peak period. If the threshold is not met for the prior year, federal COBRA does not govern plans offered in the current year.

Scenario C — Controlled group aggregation: A holding company operates 3 subsidiaries, each with 9 employees. Under IRC § 414(b) controlled group rules, all 27 employees are aggregated. All three subsidiaries are subject to federal COBRA even though none independently employs 20 workers.

Scenario D — Dental-only plan: An employer offers both a medical plan and a standalone dental plan. Each plan is evaluated separately under 26 C.F.R. § 54.4980B-2. If the employer clears the size threshold, COBRA applies to both plans independently, and a qualified beneficiary may elect continuation of one without electing the other.

Scenario E — Church plan: A private hospital operated by a religious denomination structured its health plan as an ERISA church plan under ERISA § 3(33) and has not made an election under ERISA § 410(d). Federal COBRA does not apply, regardless of how many employees the hospital has.

Decision boundaries

Determining federal COBRA applicability requires clarity on three intersecting questions. The following comparison captures the primary classification boundaries:

Factor Federal COBRA Applies Federal COBRA Does Not Apply
Employer size 20+ employees on ≥50% of prior-year business days Fewer than 20 employees on ≥50% of prior-year business days
Employer type Private-sector employers Federal government employers; most church plans
Plan type Group health plan providing medical care Life, disability, stand-alone FSA (excepted benefit), non-medical EAP
Participant count 2+ current-employee participants on plan year's first day Fewer than 2 current-employee participants

The COBRA Administration Authority index provides a structured overview of how these coverage eligibility rules connect to the broader administration and compliance obligations that follow once COBRA applicability is confirmed.

Transition from coverage determination to qualified beneficiary status: Even when an employer and plan are both subject to federal COBRA, not every individual associated with that employer automatically qualifies. The statute defines "qualified beneficiaries" as covered employees, their spouses, and dependent children who were enrolled in the plan on the day before a qualifying event. Former employees who were never enrolled, or dependents who were not covered at the time of the qualifying event, do not attain qualified beneficiary status regardless of employer or plan eligibility.

References

The law belongs to the people. Georgia v. Public.Resource.Org, 590 U.S. (2020)