Fully Insured vs Self-Funded Health Plans: Which Structure Fits Your Employer Clients?

Bottom line: Fully insured plans deliver cost predictability and state consumer protections in exchange for the carrier's profit margin and state premium taxes — typically 15–25% of premium loaded into the rate for small groups. Self-funded plans transfer claims risk to the employer but eliminate that overhead, exempt the plan from state insurance mandates under ERISA §514 preemption, and allow far greater design flexibility. The break-even depends on group size, claims history, cash reserve capacity, and industry risk profile. Traditional self-funding suits employers with 100+ stable lives; level-funded plans — a hybrid with self-funded mechanics and predictable monthly costs — extend the model to groups as small as 25. Most employers below 50 lives belong in fully insured plans. Most above 200 should be evaluating self-funding at every renewal.

How Each Structure Works

Fully insured: The employer pays a fixed monthly premium to an insurance carrier. The carrier assumes full financial responsibility for covered claims — regardless of actual claims volume during the plan year. The premium is guaranteed-cost: the employer knows its health plan cost on day one of the plan year and bears no additional obligation when claims run high. State insurance departments regulate fully insured plans under state insurance law, which means the plan must comply with state-mandated benefits and is subject to state premium taxes (typically 2–3% of premium, varying by state).

Self-funded (self-insured): The employer funds covered claims directly from its own assets as claims are submitted and adjudicated. The employer typically contracts with a third-party administrator (TPA) to process claims and provide network access, and purchases stop-loss insurance separately to cap exposure from catastrophic individual claims or aggregate claims volatility. Self-funded plans are employee welfare benefit plans under ERISA §3(1) and are regulated by federal law — not state insurance departments. This federal preemption under ERISA §514(a) is the source of most of the plan design flexibility that makes self-funding attractive to mid-market and large employers.

Who Bears the Claims Risk

This is the foundational difference between the two structures. Under a fully insured plan, claims risk rests entirely with the carrier. If claims run 40% above projections, the carrier absorbs that loss (and recaptures it at the following year's renewal through higher rates). If claims run 20% below projections, the carrier retains the surplus.

Under a self-funded plan, the employer is the plan sponsor and the claims payer. Favorable claims years produce reserve savings the employer retains. Unfavorable years — a cancer diagnosis, a premature birth, a complex surgery — fall directly on the employer's balance sheet until stop-loss coverage triggers.

The Kaiser Family Foundation Employer Health Benefits Survey (2023) found that 65% of covered workers in the U.S. were enrolled in a self-funded plan, though self-funding penetration varies sharply by group size: only 13% of workers at firms with fewer than 50 employees were in self-funded plans, versus 82% at firms with 5,000 or more employees. This distribution reflects the actuarial reality — at small group sizes, a single catastrophic claimant can represent an outsized share of annual claims, making self-funding financially unmanageable without the risk management infrastructure that only larger groups can cost-effectively deploy.

Stop-Loss Coverage: The Self-Funded Safety Net

No employer operating a self-funded plan should do so without stop-loss insurance. Two forms exist, and both are typically necessary:

Specific (individual) stop-loss caps the employer's financial obligation for any single covered individual within a plan year. The employer bears claims for each employee up to the specific deductible — commonly set between $25,000 and $150,000 depending on group size, industry, and the employer's risk tolerance — and the stop-loss carrier reimburses claims above that threshold. At a $75,000 specific deductible, a $400,000 cancer treatment costs the employer $75,000; the stop-loss carrier funds the remaining $325,000.

Aggregate stop-loss limits the employer's total claims obligation across all covered individuals during the plan year. The aggregate attachment point is typically set at 120–125% of expected annual claims. If total plan claims exceed that corridor, the stop-loss carrier reimburses the excess. Aggregate protection guards against the scenario where no single employee reaches the specific deductible, but overall claims frequency runs far above projections — multiple moderately expensive claims that collectively exhaust the reserve.

Stop-loss insurance is not health insurance under state law — it is a reimbursement contract between the stop-loss carrier and the employer, with no direct obligation to covered employees. Brokers placing stop-loss must obtain quotes separately from the TPA arrangement and renew both independently. Stop-loss contracts are typically written on a 12/12 or 12/15 basis, referring to the claims incurred and paid periods — a detail with material consequence when employers switch stop-loss carriers mid-contract. For a full treatment of attachment point selection, lasering provisions, run-in/run-out gaps, and stop-loss carrier due diligence, see the stop-loss insurance guide for self-funded plans.

Regulatory Framework: ERISA vs State Insurance Law

This dimension has more practical consequence for plan design than any other. Under ERISA §514(a), self-funded employer health plans are exempt from "any and all State laws insofar as they may now or hereafter relate to any employee benefit plan." The Supreme Court affirmed broad ERISA preemption in Shaw v. Delta Air Lines, Inc., 463 U.S. 85 (1983), and subsequent case law has continued to define its scope — including Kentucky Association of Health Plans v. Miller, 538 U.S. 329 (2003), which clarified when state insurance laws "regulate insurance" sufficiently to be saved from ERISA preemption.

Practical consequences of ERISA preemption for self-funded plans:

• Exempt from state-mandated benefits. States frequently require fully insured plans to cover specific conditions, treatments, or provider types. Self-funded plans are not subject to these mandates. An employer can exclude coverage for fertility treatment, chiropractic services, or bariatric surgery in states where those benefits are mandated in fully insured plans — or include them at precisely specified benefit levels that differ from state-required minimums.

• No state premium tax. The 2–3% state premium tax assessed on fully insured premiums does not apply to employer-funded claims. For large employers, this exclusion alone can represent hundreds of thousands of dollars annually.

• Subject to federal ACA market reforms. ERISA preemption exempts plans from state insurance mandates, not federal law. ACA market reforms — prohibition on lifetime dollar limits (§2711), coverage of adult dependents to age 26 (§2714), preventive care without cost-sharing (§2713), and prohibition on annual dollar limits on essential health benefits — apply to all employer health plans, self-funded and fully insured alike.

• Small group community rating rules do not apply. Fully insured small group plans in most states use modified community rating, spreading risk across a pool of groups. Self-funded plans bear their own actual claims experience — advantageous for healthy populations, punitive for high-risk workforces.

For brokers, the ERISA regulatory framework also shapes how employees challenge claim denials. Employees contesting coverage decisions under self-funded plans proceed under ERISA §502(a), not state insurance bad faith law. This limits recoverable damages — ERISA §502(a)(1)(B) generally allows recovery of benefits owed but not consequential damages — a distinction with practical significance when counseling clients on their administrative claims review obligations under 29 CFR §2560.503-1.

Plan Design Flexibility and ACA Compliance

Self-funded plans can be designed with specificity that standard carrier products cannot match:

• Network access and direct contracting. Employers can carve out pharmacy benefits to a specialized pharmacy benefit manager (PBM), contract directly with high-value hospital systems, or implement reference-based pricing — paying providers at Medicare rates plus a defined margin rather than at negotiated carrier contract rates. Reference-based pricing has generated significant cost savings for some self-funded employers, though it carries employee relations risk and administrative complexity when providers refuse payment.

• Benefit carve-outs. Behavioral health, specialty pharmacy, and chronic disease management can be administered by specialist vendors with outcome-based contracts, rather than bundled into a single carrier contract where performance is harder to isolate. Behavioral health carve-outs — including carved-out mental health and substance use disorder benefits administered by a separate managed behavioral health organization — must comply with MHPAEA mental health parity requirements in every benefit classification where MH/SUD benefits are covered; see How to Make Employer Health Plans Comply with Mental Health Parity Requirements for the full NQTL comparative analysis requirement that applies regardless of whether behavioral health is bundled or carved out.

• Wellness incentive design. Value-based benefit structures — reduced copays for preferred providers, premium differentials for tobacco use — are more easily implemented under self-funded plans within the bounds of HIPAA wellness rules (26 CFR §54.9802-1 and ACA §2705).

• Claims data ownership. Self-funded employers own their full claims dataset. Fully insured employers typically receive only aggregate summary data from carriers. Claims data access enables population health analytics, targeted condition management programs, and informed renewal negotiations — including the ability to model specific stop-loss scenarios using actual historical claims.

The Level-Funded Middle Ground

Level-funded plans use self-funded mechanics while presenting a predictable monthly fixed cost. The carrier or TPA bundles expected claims, administrative costs, and stop-loss premium into a single monthly "level" payment. At plan year-end, if actual claims fall below the expected threshold, the employer receives a refund of the surplus held in the claims reserve.

Level-funded plans are regulated as self-funded plans under ERISA — the employer is the plan sponsor, claims are funded from employer contributions, and ERISA §514 preemption applies. This means they carry the same state mandate exemption and no state premium tax, despite their administratively simple monthly payment structure.

They are particularly suited for groups in the 25–150 employee range where traditional self-funding creates unacceptable claims volatility but the cost of fully insured community-rated premiums in a given state is high. Level-funded plan adoption has expanded significantly since 2015, and several major carriers now market them aggressively. Broker due diligence is essential: not all level-funded arrangements are structured identically, and refund threshold mechanics — specifically whether the employer's share of the claims reserve qualifies for refund or is retained by the carrier — vary meaningfully between products.

Side-by-Side Comparison

When to Choose Fully Insured

Fully insured plans are the appropriate default for:

• Small employers under 50 lives. Limited headcount makes self-funding actuarially unstable. A single high-cost claimant in a 20-person group can represent 5% or more of that group's annual claims projection. Stop-loss underwriters price specific deductibles conservatively for small groups — often eliminating the cost advantage of self-funding entirely.

• Industries with high turnover or volatile headcount. Hospitality, construction, retail, and seasonal businesses struggle to maintain the stable census that self-funding requires for meaningful claims budgeting. A significant mid-year headcount reduction also affects aggregate stop-loss attachment points in ways that can leave the employer inadequately protected.

• Employers without cash reserves. Self-funding requires the employer to fund claims as they incur — before stop-loss reimbursement arrives (which typically takes 30–90 days after the specific deductible is reached). Employers without a dedicated claims reserve fund will face cash flow pressure during high-utilization months. A minimum reserve of two to three months of expected claims is standard practice before transitioning to self-funding.

• New businesses without claims history. Stop-loss underwriters price specific and aggregate deductibles based on prior claims experience. Without credible historical data, stop-loss terms will be less favorable, and the employer lacks the foundation for accurate budget modeling.

• Employers who value administrative simplicity. Fully insured plans shift claims adjudication, network management, appeals processing, and ACA notice compliance to the carrier. Self-funded plans require active management of the TPA relationship, stop-loss contract renewal, and coordination of point-solution vendors.

When to Choose Self-Funding

Self-funding delivers material advantages for:

• Employers with 100+ stable lives. At this size, claims data becomes statistically meaningful, stop-loss pricing becomes competitive, and the premium tax savings and carrier load elimination routinely exceed the incremental administrative costs. Most large group actuarial analyses show self-funding break-even at 75–100 lives under favorable assumptions.

• Healthy, low-risk employee populations. Professional services, technology, and white-collar workforces with younger average demographics generate below-average claims. In a community-rated fully insured pool, these employers cross-subsidize higher-risk groups. Self-funding captures those favorable demographics as retained savings rather than transferring them to the carrier's book.

• Employers that operate across multiple states. A national employer with 20 state locations faces a patchwork of state-mandated benefit requirements under fully insured plans. Self-funding reduces that complexity to a single federal ERISA standard, simplifies plan administration, and allows a consistent benefit design across all locations.

• Employers who want claims data for population health management. Detailed claims analytics — high-cost claimant identification, specialty pharmacy trend, chronic condition prevalence — require the individual-level data that self-funded plan administration provides. This data foundation supports stop-loss negotiations, vendor selection, and benefit redesign with precision that summary-level carrier reports cannot match.

• Employers planning open enrollment transitions. The move from fully insured to self-funded requires 90–120 days of preparation: TPA selection, stop-loss procurement, Summary Plan Description drafting, enrollment system configuration, and compliance notice updates. For the full compliance calendar and notice requirements that apply during that transition and every enrollment cycle, see How to Manage Open Enrollment Compliance for Employer Health Plan Clients.

Frequently Asked Questions

Can a small employer self-fund their health plan?

Technically yes — ERISA imposes no minimum headcount requirement on self-funded plans. Practically, groups under 25–50 lives face unfavorable stop-loss pricing, inadequate claims data for meaningful projections, and claims volatility that can be financially destabilizing. Level-funded plans are the more appropriate vehicle for smaller employers who want self-funded economics with managed cash flow risk.

Is a level-funded plan the same as a fully insured plan?

No. Level-funded plans are self-funded under ERISA, not insurance products under state law. They carry ERISA preemption from state-mandated benefits, and the employer is legally responsible for funding covered claims. The monthly fixed payment is an administrative structure, not a transfer of claims risk to the carrier. Brokers should confirm that the plan document, stop-loss agreement, and TPA administrative agreement all clearly reflect the self-funded structure — particularly because some carriers market level-funded products in ways that obscure this distinction.

What happens if a self-funded employer cannot pay claims?

Employers who fund claims from operating cash flow rather than a dedicated reserve can face liquidity problems during high-utilization months. Stop-loss insurance reimbursement is not instantaneous — specific deductible claims typically take 30–90 days to be submitted and reimbursed after the deductible is met. Best practice is maintaining a dedicated claims reserve fund covering two to three months of expected claims. Some employers establish a health and welfare trust under ERISA §501(c)(9) (VEBA) to hold reserve assets separately from general corporate funds, which also satisfies ERISA's fiduciary principles on plan asset management.

Does the ACA require self-funded plans to cover essential health benefits?

The ACA's essential health benefit (EHB) requirement under §1302 applies only to fully insured plans in the individual and small group markets. Large-group fully insured plans and all self-funded plans are exempt from the EHB mandate. All employer health plans — self-funded and fully insured — must comply with ACA market reforms, including the prohibition on lifetime dollar limits (§2711) and annual dollar limits on EHB-equivalent benefits, adult dependent coverage to age 26 (§2714), and preventive care without cost-sharing (§2713).

How do self-funded plans interact with HSAs and HRAs?

Self-funded plans can be designed as qualifying High Deductible Health Plans (HDHPs) compatible with Health Savings Accounts under IRC §223(c)(2) — provided the plan meets minimum deductible and out-of-pocket maximum thresholds ($1,650/$3,300 self-only/family for 2025, per IRS Rev. Proc. 2024-25). ICHRA and QSEHRA arrangements can also be layered onto self-funded plan structures for defined employee classes — for how ICHRAs work as a standalone alternative to group health, including class design, allowance benchmarking, and ACA affordability math, see How to Evaluate and Implement an ICHRA for Employer Clients. For a full breakdown of how HRA, HSA, and FSA accounts interact with different plan designs and contribution limits, see HRA vs HSA vs FSA: How Each Account Works and 2025 Contribution Limits.

Do self-funded employers need to file ACA coverage reports?

Yes. Applicable Large Employers with self-funded plans file Forms 1094-C and 1095-C to report coverage offers and enrollment, with the self-funded employer completing all sections including enrollment data. Small employers with self-funded plans (under 50 full-time equivalents) file Forms 1094-B and 1095-B. For fully insured plans, the carrier handles 1095-C distribution for its insured clients; for self-funded plans, the employer is the responsible reporting entity. For the ALE threshold determination and FTE counting mechanics that establish which reporting form applies, see ACA Employer Mandate: The 50-Employee Threshold, Coverage Requirements, and Penalties Explained.

Bottom Line

The fully insured vs self-funded decision is not a product recommendation — it is a structural financial and regulatory analysis that should be run at every renewal for any employer approaching the 100-life threshold. For small groups, fully insured is almost always the right answer. For mid-market and large employers, self-funding and the carrier load elimination it delivers is worth modeling annually. Level-funded plans have made self-funded economics accessible to smaller employers, but they require careful diligence on stop-loss construction and year-end refund mechanics before recommendation.

Your role in this analysis extends well beyond quoting premiums. Claims data review, stop-loss market access, TPA selection criteria, ERISA compliance alignment, and ACA reporting configuration — particularly for employers navigating open enrollment compliance obligations across multiple plan years — are where you create durable advisory value that no direct writer or online enrollment portal can replicate. Arvori gives benefits brokers the workflow infrastructure to run this analysis systematically, deliver clear documentation of the recommendation, and position the funding structure decision as the high-value advisory service it actually is.