ERISA and HDHP Plans

The Employee Retirement Income Security Act of 1974 (ERISA) governs the majority of employer-sponsored health plans in the United States, including high-deductible health plans offered through the workplace. Understanding how ERISA applies to HDHPs determines which rules govern plan design, disclosure, claims processing, and employee protections. This page explains ERISA's definition and scope as it applies to HDHPs, the mechanics of federal preemption, common plan scenarios, and the decision boundaries employers and plan administrators must navigate.

Definition and scope

ERISA, enacted by Congress and administered primarily by the U.S. Department of Labor (DOL), establishes minimum standards for most voluntarily established retirement and health benefit plans in private-sector employment. HDHPs offered by private employers fall within ERISA's definition of an "employee welfare benefit plan" under 29 U.S.C. § 1002(1), which covers plans providing medical, surgical, or hospital care benefits.

ERISA's reach is broad but not unlimited. Plans that fall outside ERISA's scope include:

  1. Government employer plans (federal, state, and local)
  2. Church plans that have not elected ERISA coverage under 29 U.S.C. § 1003(b)
  3. Plans maintained outside the United States primarily for nonresident aliens
  4. Plans with fewer than 1 participant who is a current employee

For HDHPs offered through private employers — which represent the dominant distribution channel given that employer-sponsored coverage reaches approximately 153 million Americans (Kaiser Family Foundation, 2023 Employer Health Benefits Survey) — ERISA is the controlling federal framework.

ERISA's preemption clause at 29 U.S.C. § 1144 supersedes state laws that "relate to" an employee benefit plan. This preemption is the central structural fact for employer-sponsored HDHPs: state insurance mandates, benefit requirements, and coverage laws generally cannot reach self-funded ERISA plans, while fully insured ERISA plans remain subject to state insurance regulation through the savings clause. The distinction between self-funded HDHP arrangements and fully insured products is therefore legally significant under ERISA.

How it works

An employer that establishes an HDHP as an ERISA plan must satisfy the Act's requirements across four primary domains:

  1. Reporting and disclosure — The plan must provide a Summary Plan Description (SPD) within 90 days of a participant becoming covered, per 29 C.F.R. § 2520.102-3. The SPD must describe HDHP deductible amounts, out-of-pocket maximums, HSA eligibility, and claims procedures in language calculated to be understood by the average plan participant.
  2. Fiduciary standards — Plan administrators and trustees managing HDHP assets (particularly relevant where employer HSA contributions flow through the plan) are fiduciaries under 29 U.S.C. § 1104 and must act solely in the interest of participants.
  3. Claims and appeals — DOL regulations at 29 C.F.R. § 2560.503-1 require that ERISA-governed HDHPs provide written notice of claim denials, specify reasons, and grant participants the right to a full and fair review. Post-ACA plans must also provide external review rights.
  4. Mental Health Parity — The Paul Wellstone and Pete Domenici Mental Health Parity and Addiction Equity Act of 2008, enforceable under ERISA, prohibits HDHP plans from applying more restrictive financial requirements to mental health and substance use disorder benefits than to medical/surgical benefits (DOL Mental Health Parity).

The Affordable Care Act layered additional requirements onto ERISA plans, including coverage of preventive services without cost sharing — a rule directly relevant to HDHP design, as HDHPs subject to IRS minimum deductible rules must still provide first-dollar preventive care coverage to preserve HSA eligibility.

Common scenarios

Scenario A: Large self-funded employer HDHP
A corporation with 5,000 employees self-insures its HDHP, using a third-party administrator. ERISA preemption shields the plan from state mandates requiring coverage of certain benefits not included in the plan document. The employer retains fiduciary responsibility, and the plan must comply with ERISA's claims procedures and SPD requirements. State insurance commissioner authority does not extend to this arrangement.

Scenario B: Small employer fully insured HDHP
A firm with 40 employees purchases an HDHP through a licensed insurer. ERISA still governs the employer's plan, but because the underlying product is an insurance contract, state insurance regulations apply to the insurer through ERISA's savings clause. The insurer must comply with state benefit mandates; the employer plan document must comply with ERISA reporting and disclosure rules.

Scenario C: Government employer HDHP
A state agency offers an HDHP to its workforce. ERISA does not apply. The plan is governed by state law, applicable collective bargaining agreements, and the ACA's market rules for governmental plans. Participants may still establish HSAs if the plan meets IRS qualification standards, but ERISA protections — including its claims appeal process — do not attach.

Comparing Scenarios A and B illustrates the practical weight of ERISA preemption: self-funded plans gain design flexibility unavailable to fully insured products operating in states with robust benefit mandates. This trade-off is central to the employer cost advantages of offering HDHPs.

Decision boundaries

Employers and benefits counsel face defined decision points when structuring an HDHP under ERISA:

Fully insured vs. self-funded — The preemption boundary shifts based on funding method. Employers in states with extensive benefit mandates frequently move to self-funding once workforce size makes risk retention actuarially viable, typically above 200 to 500 covered lives, to gain design flexibility.

HSA employer contributions as plan assets — DOL guidance clarifies that employer HSA contributions deposited directly to employee HSA custodians generally do not become plan assets, reducing fiduciary exposure. Contributions routed through an employer trust or cafeteria plan raise different questions and require specific plan document treatment.

Grandfathered plan status — ERISA plans that maintained grandfathered status under the ACA avoid certain coverage mandates, but grandfathered status is lost if HDHP cost-sharing structures change beyond defined thresholds, per 45 C.F.R. § 147.140. Employers must track plan changes to preserve or consciously relinquish this status.

COBRA applicability — ERISA HDHPs with 20 or more employees trigger COBRA continuation rights under 29 U.S.C. § 1161. Former employees electing COBRA continuation of an HDHP retain HSA eligibility only if they are not covered by other disqualifying coverage.

Enforcement jurisdiction — DOL enforces ERISA's reporting, disclosure, and fiduciary provisions. The IRS enforces the HDHP qualification rules that govern HSA eligibility. Both agencies may be implicated simultaneously when an employer-sponsored HDHP is structured incorrectly. The hdhpauthority.com index page provides a consolidated starting point for navigating the intersection of these federal frameworks.

Employers evaluating HDHP plan design should coordinate review across ERISA compliance, IRS qualification standards (annual IRS HDHP and HSA threshold updates), and ACA requirements (HDHP plans and ACA compliance) as distinct but overlapping regulatory layers.

References

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