A few years back, I sat across a conference table from a benefits director who had just finished walking me through her company’s progressive premium-sharing model. Lower-wage employees paid 10% of the health plan cost. Mid-level staff paid 20%. Highly paid executives paid 30%. Her team was proud of it, and rightly so. It helped with recruiting, cut down on turnover among frontline workers, and made the ACA affordability math almost effortless.
Then I asked a question she hadn’t heard before: “When was the last time you ran a Section 125 contributions and benefits test on this structure?”
She blinked. “We do nondiscrimination testing on the 401(k) every year. We run the ACA affordability safe harbors. Our broker said we’re fine.”
They weren’t fine. And if your organization uses any kind of variable premium sharing beyond a flat percentage or flat dollar amount, you might not be either.
The logic that gets you into trouble
Let’s pause and appreciate why tiered premium contributions are so appealing. You want your lowest-paid employees to actually use the health plan you’re offering, not waive it because the payroll deduction hurts too much. You also want to avoid the ACA’s employer mandate penalties by keeping coverage affordable. Charging people based on what they earn feels fair. It aligns with your internal equity goals. In a tight labor market, it’s a quietly powerful retention tool.
But here’s the thing: making those deductions pre-tax isn’t a given. It’s a privilege granted by Section 125 of the Internal Revenue Code, and that section has its own distinct nondiscrimination tests-separate from the ACA, separate from your 401(k) ADP/ACP testing. And the one that quietly mauls tiered-premium designs is the contributions and benefits test buried in Treas. Reg. §1.125-7(e).
How the trap actually works
The rule, boiled down, says that the amount employees are required to pay for a particular benefit cannot favor highly compensated individuals (HCIs) over non-highly compensated employees (NHCIs). Most people read that and think, “Great, my executives pay more, so I’m definitely not favoring them.”
That’s logical. It’s also incomplete. The IRS doesn’t just look for the obvious stuff. It looks at the entire contribution architecture. If there’s any path where an HCI can end up contributing less than an NHCI for the same coverage-whether in dollars or as a percentage of premium-your plan can fail. And that path doesn’t have to be deliberate. It can be a weird artifact of how your benefit administration system calculates contributions when variables like part-time hours, wellness incentives, or spousal surcharges collide.
I once reviewed a plan where a part-time NHCI was paying a higher dollar amount for employee-only coverage than a full-time HCI, simply because of the way the contribution tiers intersected with hours-based coverage levels. No one had designed it that way. It was an unintended side effect. But to an IRS examiner, that side effect looked like a discounted benefit option for highly compensated employees-and that’s all it takes to lose your cafeteria plan’s tax-favored status.
The penalty? All those pre-tax contributions-every dollar deducted for every employee-become taxable income. Retroactive to the beginning of the plan year. You’re looking at W-2c corrections, sudden tax liabilities for your workforce, a lot of difficult conversations, and potential fiduciary liability. The cost can be staggering.
Your benefits admin platform isn’t the safety net you think it is
This is the part where I get frustrated on behalf of every HR team that’s been let down by technology. Modern benefits administration systems are perfectly capable of handling tiered contribution rates. You set up employee classes by salary band or job level, assign different employer subsidies, and the system calculates the rest. It feels solid because it’s automated and the numbers balance every payroll cycle.
But I’ve yet to see a platform that proactively runs a Section 125 contributions and benefits test against those custom tiers. It’ll flag ACA affordability issues. It’ll track eligibility. It won’t tap you on the shoulder and say, “Hey, your contribution design may have just blown up your cafeteria plan’ tax status.” That testing is usually a separate, end-of-year manual process-if it happens at all-and by then, the damage is done.
How to keep the equity without the exposure
You don’t have to kill your tiered premium structure. You just have to build it the right way, from the plan document out, with a compliance-first mindset. Here’s what I tell my clients:
- Ground your tiers in broad, objective business classifications, not raw salary numbers. Use job band, hourly vs. salary, or full-time status. Then document why those classifications don’t result in HCIs getting a more favorable contribution rate than NHCIs.
- Make sure no HCI ever pays a lower dollar amount than any NHCI for identical coverage. The safest design ensures the employer subsidy percentage always stays equal or gets richer as you go down the pay scale. HCIs should consistently pay equal or more-never less-in both dollars and percentage terms.
- Put the contribution methodology in the plan document, not just in the benefits admin portal. The document is your legal foundation. The system should mirror it exactly. Lock the configuration so it can’t be casually changed during open enrollment without a legal review.
- Test early and test often. Don’t wait for year-end. Once open enrollment data settles, run a simulated cafeteria plan nondiscrimination test. If your broker or TPA can’t do it, find someone who can. I’ve seen far too many organizations learn this lesson during an IRS audit, and that’s not a classroom anyone wants to be in.
The bigger shift already underway
It’s worth noting that this Section 125 exposure is one reason I’ve seen organizations slowly pivot toward Individual Coverage Health Reimbursement Arrangements (ICHRAs). When you give employees a fixed allowance to buy their own coverage, the premium sharing happens outside the employer’s plan. No cafeteria plan, no Section 125 nondiscrimination headache. It’s not a fit for every organization, but it’s a clean escape hatch if you want to keep a progressive contribution philosophy without the tax-code gymnastics.
For the rest of you still running a traditional group plan with variable contributions: Go find your cafeteria plan document. Pull your latest nondiscrimination testing results. If you can’t show a clean pass on the contributions and benefits test, you’ve got a problem that only gets more expensive the longer you ignore it.
Take it from someone who’s had to break that news more than once-it’s a lot easier to fix now than after the IRS asks the question first.