Self-funded health plans get a lot of attention for what they can do: more control over plan design, more transparency into where the money goes, and the possibility of keeping what you don’t spend. That’s all true. But moving to a self-funded model without understanding stop-loss insurance means taking on more risk than you might want.
Stop-loss is the mechanism that keeps a catastrophic claims year from turning into a financial disaster. It’s the foundation that makes self-funding viable in the first place, but somehow it’s still one of the pieces employers most often underestimate before they make the switch.
The Risk Side of Self-Funded Health Plans
With a fully insured plan, you pay a fixed monthly premium and your carrier absorbs whatever claims come in. Expensive year for your employees? The carrier eats it. A year where everyone stays healthy? The carrier smiles all the way to its bank. You pay the same either way.
Self-funded health insurance flips that model. You pay claims as they come in rather than a fixed premium upfront. When your workforce stays relatively healthy and claims run low, you keep the difference. That’s the upside.
The downside is real exposure. Cancer diagnoses, premature births, serious injuries requiring months of hospital care: these claims can run $300,000, $500,000, or more. Your plan pays all of it. You often don’t see it coming, either. A perfectly healthy employee can receive a serious diagnosis next month. A standard delivery can turn into a premature birth with a 90-day NICU stay. Neither shows up in your workforce demographics until it happens.
Keeping claims dollars in-house is exactly what makes self-funding attractive. It’s also what leaves you exposed when one claim goes catastrophic. That’s where stop-loss insurance comes in. It helps you keep most of that upside, while protecting against much of that risk.
How Stop-Loss Insurance Works
Stop-loss insurance is coverage your plan purchases from a separate carrier to cap your financial exposure when claims get expensive.
The structure works like this: you set an attachment point. That’s the dollar threshold at which stop-loss kicks in. Set it at $75,000 per employee, and your plan pays claims normally as they come in. Once any single employee hits $75,000 in claims for the plan year, stop-loss covers everything above that for the rest of the year.
Think of it like a circuit breaker. Once a claim trips the threshold you’ve set, the switch flips and the stop-loss carrier absorbs what’s left. Your plan keeps running without the lights going out.
Stop-loss works on a plan-year basis. When the year ends, the clock resets. An employee who generated $200,000 in claims this year starts at zero next year. You’re not carrying a running tally across plan years. You aren’t getting credit for what you paid last year for that employee. A new year means a new attachment point.
That’s worth knowing if you have employees managing expensive, ongoing conditions. The attachment point resets, but your stop-loss carrier sees last year’s claims history at renewal time. It may raise your premiums or adjust your coverage terms to account for the risk it now knows about. The year resets clean. The renewal conversation doesn’t.
Your attachment point directly affects your premium. A lower attachment point means stop-loss kicks in sooner, and your premium is higher. A higher attachment point means you’re holding more risk. As a result, your premium is lower.
Common thresholds range from $25,000 on the lower end to $150,000 or more for larger employers. The right level depends on your employee count, your claims history, and the amount of short-term exposure your plan and budget can absorb. Companies in industries with physically demanding work or older workforces carry different risk profiles, and their attachment points should reflect that.
Specific vs. Aggregate Stop-Loss Insurance: 2 Types of Coverage You Need
Their are two types of stop-loss insurance, and a well-designed self-funded plan uses both.
- Specific stop-loss insurance is per-employee protection. It’s the circuit breaker described above. Each covered employee has an individual attachment point, and the stop-loss carrier takes over once their claims cross it.
- Aggregate stop-loss insurance protects the plan as a whole. Rather than tracking per-person claims, aggregate looks at total plan spend across your entire workforce. When combined claims exceed a set percentage of your expected annual spend (often around 125%), aggregate stop-loss kicks in to cover what’s above that line.
The carrier sets the expected claims figure at the start of the plan year based on your employee demographics, historical data, and industry benchmarks. That figure becomes the baseline for your aggregate attachment point. The higher your expected claims, the higher the aggregate threshold in raw dollars, even when the percentage stays constant.
Here’s what that looks like in practice. Say your plan projects $800,000 in annual claims. Your aggregate coverage kicks in at $1 million. It’s a rough year: several employees with serious conditions, more hospitalizations than usual, and claims running persistently higher than projected. By October, you’ve hit $1 million in total claims. From that point, the aggregate carrier picks up the rest. You’re not looking at a $1.4 million claims year. You’re capped at $1 million.
Specific stop-loss protects you from one catastrophic claim. Aggregate stop-loss protects you from a catastrophic year. A correctly designed self-funded plan typically uses both, with attachment points calibrated to your actual workforce size and demographics.
What Separates a Strong Stop-Loss Policy From a Weak One
- The attachment point is a strategic decision, not just a number. Set it too high, and you’re absorbing a significant chunk of large claims before stop-loss engages. That might work for a 200-person company with a stable workforce and solid claims history. For a 35-person company where one serious illness can shift the whole claims picture, that’s a different story. Set it too low, and your premium starts eating into the savings that made self-funding worth pursuing.
Employers moving to self-funded for the first time are working with projections rather than real claims history. An experienced employee benefits consultant can help close that gap by drawing on data from similarly sized companies in comparable industries to set an appropriate attachment point. - Claims-basis differences matter at year-end. Some policies are issued on a “claims-paid” basis, meaning a claim only counts toward your attachment point when it’s paid within the plan year. Others run on an “incurred” basis. The difference shows up when large, in-progress claims haven’t fully resolved before the plan year closes.
- Laser exclusions can change the picture. A stop-loss carrier can, in some cases, exclude specific high-cost employees from coverage or set a much higher individual attachment point for them. It’s the carrier’s way of limiting its own exposure on a known risk. Employers need to know when a laser is in place and factor it into their overall plan design. A laser on a key employee can create a significant, expensive coverage gap if you’re not prepared for it.
If your provider wants to include an exclusion like this, your broker should help you understand what that means, how it affects your risk profile, and what options you have. - Renewal terms deserve the same attention as the initial policy. Many carriers reserve the right to significantly increase premiums or add lasers at renewal based on your prior year’s claims. What your stop-loss carrier can do after a bad year is almost as important as what it covers during one.
Self-Funding Without Stop-Loss Is Just Exposure
The self-funded model is about holding the right risk: the predictable, manageable claims you can absorb, while transferring the catastrophic risk to a stop-loss carrier. That’s the whole design.
Without stop-loss insurance, you’re just holding everything.
The Benefit Doctor helps employers build self-funded plans where stop-loss coverage is built in from the start, with specific and aggregate thresholds calibrated to your actual workforce.