Stop-Loss Insurance for Self-Funded Health Plans: Specific vs. Aggregate Coverage Explained
Stop-loss insurance is the financial protection that makes self-funded health plans viable for most employers. Without it, a single catastrophic claim — a premature birth, a cancer diagnosis, an organ transplant — can create an unplanned seven-figure liability that threatens operating cash. Self-funded plans under ERISA require the employer to pay covered claims from its own assets as they are incurred. Stop-loss doesn't change that legal obligation; it reimburses the employer after it pays. Understanding how specific and aggregate stop-loss coverage work, how to set appropriate attachment points, and which contract terms determine whether a claim is actually covered is the core technical competency for any benefits broker advising clients on self-funded arrangements.
What Stop-Loss Insurance Is — and What It Isn't
Stop-loss insurance (also called excess loss insurance) is a contract between the stop-loss carrier and the employer — not between the carrier and individual plan participants. This distinction is legally significant. Stop-loss carriers are not subject to state insurance mandates or ACA market reforms as applied to individual or group health insurance, because stop-loss is classified as a separate commercial insurance product that reimburses the employer. Plan participants have no direct claim against the stop-loss carrier. Their claims run through the plan; the employer pays those claims and then separately seeks reimbursement from its stop-loss policy.
State regulation of stop-loss varies considerably. The NAIC Model Stop Loss Insurance Act (adopted in various forms by many states) sets minimum standards for attachment points to prevent very low-deductible stop-loss from functioning effectively as individual health insurance. Some states impose specific minimum deductibles — California requires individual specific deductibles of at least $40,000 under Cal. Ins. Code §742.20. Brokers placing stop-loss must verify applicable state minimums or risk a placement that does not comply with state filing requirements.
Employers purchase stop-loss either through their TPA (third-party administrator) as a bundled arrangement or through a standalone stop-loss carrier placed separately. Major carriers include Sun Life, Symetra, HM Life, Tokio Marine HCC, and Voya. Many large TPAs have preferred carrier relationships or proprietary stop-loss products. Brokers should evaluate whether a TPA-bundled stop-loss arrangement is truly competitive against standalone market options — the bundled convenience often comes at a pricing premium that mid-market groups can avoid by shopping independently.
The Two Coverage Types: Specific and Aggregate
Every self-funded plan should carry both specific and aggregate stop-loss, though technically each can be purchased independently. The two layers protect against different types of claims risk and together cap total plan exposure to a manageable range.
Specific Stop-Loss (Individual Stop-Loss)
Specific stop-loss protects against catastrophically large individual claims. The employer sets a specific attachment point (also called the specific deductible or individual deductible) — the per-person threshold above which the stop-loss carrier reimburses covered claims incurred by a single participant within the plan year.
Example: A group with a $100,000 specific attachment point self-funds the first $100,000 of each individual's covered medical claims in the plan year. An employee diagnosed with leukemia who incurs $400,000 in covered claims triggers specific stop-loss reimbursement of $300,000 — the amount above the $100,000 attachment point. The employer's maximum obligation for that individual is capped at $100,000 regardless of how high claims ultimately run.
Specific attachment points for mid-market groups (200–500 employees) commonly range from $75,000 to $250,000, based on the group's risk tolerance, claims history, and the premium differential between deductible levels. Larger groups with sophisticated risk programs sometimes self-insure all specific risk above a higher attachment point and rely only on aggregate protection.
Lasering: Stop-loss carriers can exclude or surcharge coverage for specific high-risk individuals at renewal — a practice called "lasering." A laser carves out a named participant and sets a higher individual attachment point (or full exclusion) for that person. Lasering protects the carrier but transfers concentrated risk back to the employer for that individual. Brokers should negotiate at-renewal lasering restrictions in the original contract, or choose carriers that contractually prohibit lasering of participants who were enrolled at policy inception. Groups facing surprise renewal lasering on a high-cost claimant may need to evaluate transitioning that individual to an ACA marketplace plan, restructuring the specific deductible, or moving the entire group back to a fully insured arrangement.
Aggregate Stop-Loss
Aggregate stop-loss protects against the scenario where overall plan claims run higher than projected — not because of one catastrophic individual, but because many participants had elevated claims that collectively strain the reserve. The employer sets an aggregate attachment point (the aggregate deductible), typically expressed as a percentage of projected annual claims — most commonly 125%.
Example: A 300-employee group projects $3,000,000 in annual claims. The aggregate attachment point at 125% equals $3,750,000. If actual annual claims (net of specific stop-loss recoveries) reach $4,200,000, aggregate stop-loss reimburses the $450,000 excess above the attachment point.
Aggregate coverage effectively caps total net plan cost at roughly 125% of expected claims for the year (after specific stop-loss recoveries offset the largest individual claims). This cap is the budget predictability mechanism that makes self-funding viable for groups that cannot absorb open-ended aggregate claims exposure.
Monthly aggregate accommodation: Most aggregate stop-loss policies pay out at year-end, once annual claims are confirmed. A monthly aggregate accommodation allows the employer to draw on aggregate reimbursements during the plan year once monthly claims are tracking significantly above projection. This eliminates the cash flow gap that can strain employer finances mid-year when claims are running hot. Brokers should negotiate monthly accommodation for groups where interim cash flow pressure would be a concern; most carriers offer it at modest additional premium.
Key Contract Terms Brokers Must Understand
Policy Period vs. Run-In/Run-Out
Stop-loss policies cover claims incurred and paid during defined periods. The interaction between these periods creates basis risk that can leave employers with uncovered large claims.
- Run-in (prior period claims): Claims incurred before the policy effective date but paid during the current policy year. Without run-in coverage, a group converting from fully insured to self-funded in January has no stop-loss coverage for large December claims that are processed and paid in January.
- Run-out (terminal liability): Claims incurred during the policy year but paid after the policy expires. A group that terminates self-funding or switches stop-loss carriers at year-end faces run-out exposure for claims adjudicated after the prior carrier's cutoff date, unless the prior policy includes an extended run-out period or the new carrier provides run-in.
The most protective structure is a paid/paid contract — covering all claims paid during the policy year regardless of when incurred — which eliminates both run-in and run-out gaps entirely. Many carriers instead quote 12/12 (incurred and paid within the same 12-month policy period), which creates the gaps above. Brokers must identify which contract structure applies and model the resulting exposure for groups with large near-year-end claims patterns.
Specific Deductible Accumulation
Specific stop-loss accumulates toward the attachment point based on whether the policy uses a plan year or calendar year basis, and whether claims trigger on a paid or incurred date. A group on a fiscal plan year with a calendar-year specific stop-loss policy faces periods of misalignment where year-end large claims straddle two policy periods — each half falling below the attachment point and neither triggering reimbursement. Confirm that the stop-loss policy year is coterminous with the plan year.
Named Participant vs. Any-One-Person Coverage
Most stop-loss policies cover claims for any enrolled participant. Some policies require named participant scheduling — the employer provides a roster at policy inception and only participants on that roster receive specific stop-loss coverage. Named participant structures may exclude late-enrollees or HIPAA special enrollees who join after the policy's enrollment window. Confirm coverage for mid-year enrollees, particularly for groups with meaningful turnover or with employees in active qualifying life event periods.
Setting the Right Specific Attachment Point
The attachment point is the most consequential coverage decision in stop-loss placement. Setting it too low costs premium without proportionate protection; setting it too high leaves the employer exposed to large individual claims that proper stop-loss structure would cover.
A standard approach: run a maximum probable loss analysis using the group's claims history (or actuarially credible industry data for smaller groups without credible experience) to identify the 95th-percentile individual claim. Set the specific attachment point at or slightly above that threshold — the employer self-insures below it, the stop-loss carrier covers above it.
For groups without credible claims history (fewer than 100 employees or fewer than 36 months of data), carriers use manual rates based on demographics, SIC code, and geography. Brokers should obtain at least 24 months of large claimant data (all claims over $50,000) from the incumbent fully insured carrier as part of any self-funding feasibility analysis. Carriers are generally required to provide this data under HIPAA on request from the employer — and it is almost always available.
Common attachment point ranges by group size:
| Group Size | Typical Specific Deductible | Aggregate Attachment |
|---|---|---|
| 50–150 employees | $50,000–$100,000 | 125% of expected claims |
| 150–500 employees | $100,000–$200,000 | 125% of expected claims |
| 500–2,000 employees | $150,000–$400,000 | 125% of expected claims |
| 2,000+ employees | $300,000–$1,000,000+ | Aggregate sometimes dropped |
Shopping and Placing Stop-Loss Coverage
Stop-loss is placed at the commercial lines level, not through the group health market. The submission package should include:
- 24–36 months of monthly claims data (total incurred, paid, and a large claimant schedule for all claims over $50,000)
- Current plan document and benefit summary
- Group demographics (age/gender distribution, SIC code, geography)
- Current TPA agreement and network access information
Lead time for competitive stop-loss quoting is typically 45–60 days before the effective date. Last-minute submissions — especially for groups with large claimant history — reduce carrier participation and deteriorate pricing.
Carrier financial strength matters in a way that does not apply to licensed health insurers. Stop-loss carriers are not covered by state guaranty funds that protect insureds when licensed health insurance carriers fail. If a stop-loss carrier becomes insolvent, the employer has an unsecured creditor claim against the carrier's estate. Place stop-loss only with carriers rated A- or better by AM Best.
For employer clients evaluating whether to convert from fully insured to self-funded, the fully insured vs. self-funded comparison guide covers how stop-loss interacts with the broader funding decision, including level-funded plan mechanics and the ERISA preemption benefits that drive most mid-market employers toward self-funding.
How Stop-Loss Interacts with ACA and ERISA Compliance
Self-funded plans are subject to most ACA provisions — including the employer mandate's minimum value and affordability requirements, the prohibition on annual and lifetime dollar limits on essential health benefits (ACA §2711), coverage of adult dependents to age 26 (ACA §2714), and preventive care without cost-sharing (ACA §2713). Stop-loss does not help employers satisfy ACA compliance obligations; it only protects against claims losses once the plan is operating legally. Employers that structure self-funded plans to avoid ACA requirements face plan-level penalties under IRC §4980H independently of any stop-loss arrangement.
ACA employer shared responsibility obligations apply based on the employer's applicable large employer status regardless of funding structure. For a complete breakdown of the ALE determination rules, FTE counting, and §4980H penalties, see the ACA employer mandate guide.
Self-funded plans also remain fully subject to MHPAEA's mental health parity requirements — stop-loss carriers bear no responsibility for the plan's parity compliance. Brokers advising self-funded clients on benefits design should review the mental health parity compliance guide to understand the NQTL comparative analysis requirements and DOL enforcement risk under the 2024 final rule.
At open enrollment, self-funded plan administrators must distribute required ERISA and ACA notices on the same schedule as fully insured plans — the self-funded status does not reduce notice obligations. For notice requirements, election documentation, and HIPAA special enrollment administration, see the open enrollment compliance guide.
Common Mistakes Benefits Brokers Make with Stop-Loss
Mismatching the stop-loss policy year and plan year. The stop-loss policy year should be coterminous with the plan year. Any misalignment creates gap exposure at year boundaries for large claimants who straddle two policy periods.
Failing to arrange run-in coverage on first-year conversions. Groups converting from fully insured plans need run-in coverage (or a paid-based prior policy trigger) or they hold uninsured exposure for large claims incurred in the final months under the prior carrier but processed in the new self-funded year.
Ignoring lasering provisions at placement. Brokers who place stop-loss without reviewing the carrier's contractual at-renewal lasering rights expose clients to sharp renewal premium increases or sudden coverage exclusions for high-cost participants.
Choosing the lowest-priced carrier without AM Best verification. Stop-loss is not state-guaranteed. An insolvent carrier means no reimbursement. The premium savings from a non-investment-grade carrier are not worth the risk. Verify the AM Best rating before binding.
Defaulting to 125% aggregate without a cash reserve analysis. A group with thin operating margins and limited cash reserves may not be able to fund the corridor between expected claims and the 125% attachment point if claims run high. Groups in that position may need a tighter aggregate attachment — 115% or even 110% — even at meaningfully higher premium.
Not modeling pharmacy claims separately. Specialty drug costs have risen sharply; individual specialty medications can exceed $500,000 annually. Employers without pharmacy cost management strategies embedded in their PBM contracts often find that specific stop-loss claims are driven primarily by specialty drug utilization — and that a low specific deductible is necessary to contain that exposure.
FAQs: Stop-Loss Insurance for Self-Funded Plans
Can a small employer with 50 employees use stop-loss insurance?
Yes, though the economics for very small groups often favor level-funded plans rather than traditional self-funding with separately placed stop-loss. Level-funded plans use self-funded mechanics — including specific and aggregate stop-loss built into the plan structure — but present as a predictable fixed monthly payment, providing stop-loss protection without the administrative complexity of running a fully self-administered arrangement. For groups between 25 and 100 employees, level-funded arrangements are typically more practical and more cost-competitive than standalone self-funding with independently placed stop-loss.
Is stop-loss insurance subject to state insurance regulation?
Stop-loss occupies a regulatory gray zone. It is not regulated under state health insurance laws — it is a contract with the employer, not coverage for individuals — but most states regulate it as a commercial lines or specialty insurance product. Many states impose minimum specific attachment point requirements to prevent very low-deductible stop-loss from functioning as de facto small group health insurance. The NAIC Model Stop Loss Insurance Act provides a framework, but state adoption varies. Brokers must verify applicable state requirements in each state where they place stop-loss coverage before binding.
What is a corridor in aggregate stop-loss?
The corridor is the gap between expected claims and the aggregate attachment point. If expected claims are $2,000,000 and the attachment point is set at 125% ($2,500,000), the corridor is the $500,000 between expected and the threshold. The employer bears full financial risk within the corridor without reimbursement from the stop-loss carrier. Some contracts set the corridor using a fixed dollar amount rather than a percentage, which can be more favorable for groups with highly predictable claims patterns.
What is spec pooling in a level-funded plan?
Spec pooling (specific pooling) is the mechanism in level-funded plans where individual high-cost claims above a pooling threshold are removed from the employer's experience and absorbed by the pool before the TPA or carrier reprices the plan at renewal. This functions like a specific stop-loss from the employer's perspective but the risk transfer occurs at the product level rather than through a separately placed stop-loss policy. Spec pooling thresholds typically range from $40,000 to $100,000 per individual depending on the plan design. Understanding the pooling threshold and the carrier's contractual right to change it at renewal is essential due diligence when placing a client in any level-funded product.
Does stop-loss cover pharmacy claims?
Standard stop-loss policies cover both medical and pharmacy claims unless the contract specifically carves out pharmacy. As specialty drug costs have increased substantially — individual specialty medications routinely exceed $200,000–$500,000 annually — specific stop-loss has become a primary protection mechanism against pharmacy-driven catastrophic claims. Employers without specialty drug cost containment programs embedded in their PBM contract often find that most specific stop-loss claims originate from specialty pharmacy utilization rather than facility or professional claims.
What happens to stop-loss coverage when an employee is terminated?
Once an employee terminates enrollment in the self-funded plan, the employer's claims obligation under ERISA ends (subject to COBRA continuation rights). Specific stop-loss coverage for that individual terminates with plan enrollment. Claims incurred before termination but paid after termination may or may not be covered depending on the stop-loss contract's run-out provisions — this is a common source of post-termination claims disputes between employers and stop-loss carriers. Confirm run-out coverage terms and plan-level claims submission deadlines before finalizing any stop-loss placement.
How should brokers prepare clients for the stop-loss renewal process?
The renewal submission should be prepared 60–90 days before the policy anniversary. Gather 24 months of updated claims data, including any large claimant status changes (resolved, ongoing, or new high-cost individuals). Identify any enrollees the incumbent carrier may laser at renewal and model the financial impact of exclusion. If any current high-cost claimants are candidates for disease management or case management programs, document those interventions — carriers consider active case management when pricing renewals. And evaluate whether the existing carrier's renewal terms are competitive against the open stop-loss market, since loyalty pricing advantages are limited in this segment and competitive quoting almost always yields better economics for the employer.
Stop-loss insurance is not a commodity. The structure of the contract — attachment points, policy period triggers, run-in and run-out provisions, aggregate accommodation terms, and lasering restrictions — determines whether a large claim is actually covered or falls into a gap that lands back on the employer's balance sheet. Brokers who master these mechanics provide clients with real financial protection. Those who treat stop-loss as an afterthought to the health plan placement routinely discover the gaps only when a claim is denied.
Arvori connects benefits brokers with CPA partners who advise the same employer clients on compensation strategy, entity structure, and tax planning — including the tax treatment of self-funded plan costs and stop-loss premiums. Learn how the Arvori referral network works.