Business Leaders Beginner 9 min read

What Is Stop-Loss Insurance and Why Every Self-Funded Employer Needs It

Stop-loss insurance is the mechanism that caps an employer's financial risk under a self-funded health plan. Here's how it works, what it costs, and why it makes alternative plan structures safe even for small companies.

By Kingsfoil Health Editorial Team, Employer Benefits Desk Published April 24, 2026

Key takeaways

Stop-loss insurance is a separate policy that caps an employer's financial exposure under a self-funded or level-funded health plan.
There are two types: specific stop-loss (protects against any one employee's claims exceeding a threshold) and aggregate stop-loss (protects against total group claims exceeding projections).
Without stop-loss, a single catastrophic claim could sink a small employer's plan. With it, the worst-case outcome is defined and predictable.
Specific attachment points are dollar thresholds; aggregate is typically expressed as a percentage above projected annual claims. Both are negotiated based on group profile and risk tolerance.
Stop-loss is non-negotiable for any self-funded or level-funded plan — the question isn't whether to buy it, but how much coverage to buy and from which carrier.

The first objection almost every business owner raises when they hear about self-funded health insurance is the same: what happens when one of our employees has a catastrophic medical event? It’s a reasonable concern. A single serious illness or surgery can generate hundreds of thousands of dollars in claims. If you’re funding claims directly, how do you protect against that?

The answer is stop-loss insurance. It’s the mechanism that makes self-funded and level-funded plans work for companies that aren’t Fortune 500s. It caps your worst-case exposure at a defined threshold, and it’s the reason a 40-employee business can confidently run a self-funded plan without lying awake worrying about a single catastrophic medical event.

Here’s what stop-loss insurance actually is, how it protects your plan, what it costs, and what to look for when you buy it.

What is stop-loss insurance?

Stop-loss insurance is a separate insurance policy that caps an employer’s financial exposure under a self-funded or level-funded health plan. It doesn’t replace your health plan — it sits behind it, acting as a backstop that kicks in when claims cross a defined threshold.

Here’s the structure. Under a self-funded plan, your company pays medical claims directly as they’re incurred. For most months, that’s routine — regular doctor visits, prescriptions, a handful of minor procedures. But occasionally, a claim comes in that’s orders of magnitude larger than normal: a major surgery, a cancer diagnosis, a premature birth with NICU care. That’s when stop-loss kicks in.

Stop-loss isn’t a nice-to-have for self-funded plans. It’s the piece of the structure that transforms “unlimited potential claims exposure” into “defined, bounded financial risk.” Without it, a self-funded plan for a small or mid-sized employer is financially irresponsible. With it, self-funding becomes a calculated, manageable decision.

The two types of stop-loss

There are two kinds of stop-loss coverage, and most employers carry both because they protect against different scenarios.

Specific (individual) stop-loss

Specific stop-loss — sometimes called individual stop-loss — protects against any single covered person’s claims exceeding a threshold. You set that threshold (called the specific attachment point) when you buy the policy.

For illustration: imagine your specific attachment point is $75,000. If any one employee (or covered dependent) incurs more than $75,000 in medical claims over the plan year, the stop-loss carrier reimburses your plan for everything above that amount.¹

The right attachment level involves a trade-off: lower attachment points mean more protection but higher premiums; higher attachment points mean more employer risk but lower stop-loss cost. Your advisor will recommend a level based on your group size, demographics, claims history, and risk tolerance.

Aggregate (group-wide) stop-loss

Aggregate stop-loss protects against your whole group’s total claims running higher than expected — even if no single person hits the specific attachment point.

For illustration: imagine a plan year where many employees each have moderate-but-significant claims. No single person has a catastrophic event, but the cumulative total is much higher than projected. Aggregate stop-loss covers that scenario.

The aggregate attachment point is set at a percentage above your expected annual claims when the policy is written. If your expected claims for the year were $500,000 and your aggregate attachment was set at 125%, aggregate stop-loss would kick in once total claims exceeded $625,000.¹

Together, specific and aggregate stop-loss create a double layer of protection: one catastrophic claim can’t sink you, and a cumulatively bad year can’t either.

Aggregate vs. Specific Stop-Loss walks through the differences in much more depth, including how to decide what attachment points are right for your group.

How stop-loss actually protects your plan

The best way to see the protection is through a scenario. Imagine a 50-employee company with a self-funded plan. Assume their expected annual claims are $500,000 and they’ve purchased:

Specific stop-loss at a $75,000 attachment point
Aggregate stop-loss at 125% ($625,000 attachment point)

Now imagine three different plan-year outcomes:

Scenario A: Average year. Total claims come in at $480,000. No individual exceeds $75,000. Aggregate is under $625,000. Stop-loss doesn’t pay out — the employer absorbed normal variability, and no protection was triggered.

Scenario B: One catastrophic claim. One employee needs a $400,000 surgery. Total group claims are $800,000 (the $400k surgery plus $400k of normal claims). Specific stop-loss reimburses $400,000 − $75,000 = $325,000 to the employer. The employer’s net exposure on that individual is capped at $75,000.

Scenario C: Bad year across the whole group. No single person exceeds $75,000, but total claims hit $750,000. Aggregate stop-loss reimburses $750,000 − $625,000 = $125,000 to the employer. The employer’s worst-case is capped at the 125% expected-claims threshold.

In every bad-outcome scenario, the employer’s financial exposure is defined and predictable. That’s what stop-loss buys you.

Stop-Loss Insurance Explained with Real Examples walks through more scenarios with different plan sizes and attachment points if you want to see the numbers play out more fully.

What stop-loss insurance costs

Stop-loss premiums are priced based on:

Group size. Larger groups get better per-employee rates.
Workforce demographics. Age, gender mix, and location affect expected claims.
Claims history. If you have prior claims data (common for groups moving from fully-insured with 2+ years of data), carriers use it to set rates.
Attachment points. Lower attachment points are more expensive because they expose the stop-loss carrier to more claims.
Plan design. Richer plans produce more claims, which raises stop-loss costs.

Specific premium amounts depend heavily on group size, demographics, claims history, and selected attachment levels. The right way to evaluate stop-loss cost is to get actual quotes for your group, model them against your expected claims, and stress-test the worst-case scenarios.

The most important point about stop-loss pricing: the cheapest policy isn’t always the best one. A low-premium stop-loss policy might come with aggressive lasering, tight exclusions, or a carrier with thin financial ratings. Those savings disappear fast if you hit a real claim and the carrier doesn’t pay.

The premium is the easy part to compare. What matters more is the contract terms — lasering provisions, exclusions, carrier ratings, and how the policy handles run-in and run-out claims. A higher-priced policy from a strong carrier is often a better deal than a cheaper policy from a carrier that will find reasons not to pay.

What to look for in a stop-loss policy

Not all stop-loss policies are created equal. Here are the contract terms that actually matter:

Lasering. This is when the carrier identifies a specific high-risk individual in your group and sets a higher individual attachment point just for them. For illustration: if your standard specific attachment is $75,000 but one employee has a known high-cost ongoing condition, the carrier might laser them at a much higher individual attachment point. That means you’re absorbing more risk for that individual. Always ask whether lasering is included, and at what levels.

Rate caps on lasering. Some policies include rate caps that limit how much the carrier can raise premiums or adjust lasering at renewal. These are employer-friendly provisions worth asking about.

Known conditions and exclusions. Some policies exclude claims related to pre-existing conditions known when the policy was written. This can create significant gaps in coverage. Look for policies with broad coverage language and few exclusions.

Paid vs. incurred basis. A paid contract covers claims paid during the policy period. An incurred contract covers claims incurred during the policy period regardless of when they’re paid. Incurred is generally more protective but may have run-in/run-out periods that matter at transitions.

Terminal liability / run-off. What happens to claims incurred during your policy year but not paid until after it ends? Good policies include terminal liability provisions so you’re covered for the tail.

Carrier financial strength. This is insurance backing your insurance — the carrier needs to be there when you need them. Look for A.M. Best ratings of A- or better.

Who sells stop-loss insurance?

The major stop-loss insurance carriers include specialty underwriters like Sun Life, Symetra, Voya, HM Insurance Group, Tokio Marine HCC, QBE, and BCS Insurance, along with the stop-loss arms of major health carriers (Aetna, Cigna, BlueCross, UnitedHealthcare). There are also smaller regional carriers that can be competitive for specific geographies or group types.

Shopping stop-loss is something a good benefits advisor does as a matter of course at each renewal. Premiums can vary widely across carriers for the same group, which makes this an area where “we always use the same carrier” is rarely the right answer. The right carrier for your group this year may not be the same as last year.

Why this matters for small employers

The single most important reframe stop-loss provides is that it turns an unlimited risk into a bounded one. Before stop-loss, a 40-employee company “going self-funded” sounded like a small business betting the farm. With stop-loss, it’s a calculated financial decision with a defined worst case.

That reframe is what opens up level-funded plans and self-funded structures to small and mid-sized employers. The math simply doesn’t work without it. It does work with it — and for a healthy group, it works better than the fully-insured default.

One thing to remember

Stop-loss insurance is the piece of the puzzle that makes alternative plan structures financially safe for employers of every size. It caps your exposure, defines your worst-case, and lets you capture the savings of self-funding without taking on catastrophic risk. For any employer considering a self-funded or level-funded plan, stop-loss isn’t optional — it’s the foundation of the whole structure.

The question you should be asking isn’t whether to carry stop-loss. It’s what attachment points and contract terms are right for your group, and which carrier is writing the best coverage for you this year.

Trying to make sense of a stop-loss quote? We can review the attachment points, lasering provisions, and contract terms and tell you honestly whether the coverage is right for your group. Talk to us.

All dollar amounts in this article (attachment points, expected claims, illustrative scenarios) are illustrative examples for explanation. Actual stop-loss attachment points, premiums, and reimbursement amounts vary by group size, demographics, claims experience, and carrier. Specific numbers in your quote will reflect your particular group’s profile. ↩ ↩²

Frequently asked questions

What is stop-loss insurance in healthcare?

Stop-loss insurance is a financial protection policy that employers with self-funded or level-funded health plans buy to cap their exposure to large claims. It sits behind the health plan — the employer pays claims directly up to a defined threshold, and the stop-loss carrier reimburses the employer for claims above that threshold. It's what makes self-funded plans financially viable for companies that aren't large enough to absorb catastrophic risk on their own.

Who needs stop-loss insurance?

Any employer with a self-funded or level-funded health plan needs stop-loss insurance. Fully-insured plans don't need it because the carrier already takes on all claims risk. For self-funded arrangements, stop-loss is non-negotiable — without it, a single catastrophic medical event could blow up the plan budget.

How much does stop-loss insurance cost?

Stop-loss premiums vary based on group size, demographics, claims history, and the attachment points you choose. Lower attachment points (more protection) mean higher premiums; higher attachment points (more employer risk) mean lower premiums. Your benefits advisor models the trade-off based on your specific group.

What is the difference between specific and aggregate stop-loss?

Specific stop-loss protects against claims from any single covered person exceeding a defined dollar threshold for the year. Aggregate stop-loss protects against total claims from the whole group exceeding an expected amount (typically expressed as a percentage above projected annual claims). Most employers carry both types — they protect against different failure modes.

What happens if my stop-loss carrier goes out of business?

This is why carrier financial strength matters. Major stop-loss carriers carry strong A.M. Best ratings and are regulated as insurance companies, so the risk of insolvency is low. If it did happen, state guaranty associations typically cover claims up to statutory limits, and any unpaid claims could be pursued through the bankruptcy process. Your benefits advisor should only place you with highly-rated carriers for exactly this reason.

Is stop-loss insurance the same as reinsurance?

They're similar but not identical. Both are insurance purchased to cap risk on another insurance product. 'Stop-loss' is the specific term used in the employer health plan market, where the coverage is purchased directly by the self-funded employer. 'Reinsurance' typically refers to coverage that one insurance company buys to cap its own exposure — though the terms are sometimes used interchangeably in conversation.

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