Premium Only Plan Document: What the IRS Requires (Even When Employers Skip It)

Plain English Benefits · Updated October 21, 2026 · Education, not tax advice

Yes, your premium-only plan needs a written plan document. The IRS requires it under Section 125. Your payroll provider may not have mentioned it. Your broker may have said you are all set. But if you are deducting health insurance premiums on a pre-tax basis, you are operating a cafeteria plan, and cafeteria plans require a written document. Saying "we just do pretax" is not a substitute.

The document does not need to be elaborate. It does not need a lawyer. But it does need to exist, and it needs to cover the elements the IRS lists in its regulations. Most employers skip this step entirely, and most get away with it until an audit. Then the deductions are reclassified as taxable, penalties apply, and the fix is retroactive.

We will walk through what the document must contain, where the requirement comes from, and how to get compliant without hiring a benefits attorney.

What a Premium-Only Plan Document Is

A premium-only plan is the simplest form of Section 125 cafeteria plan. It lets employees pay their health insurance premiums with pre-tax dollars instead of after-tax dollars. That pre-tax treatment lowers their taxable wages, which lowers the income tax and FICA withholding on every paycheck.

The plan document is the written description of how your plan works. It names the benefits covered, the eligibility rules, the election process, when employees can change their elections, and who administers the plan. It is the legal foundation that makes the pre-tax deduction permissible under IRS rules.

Without the document, you do not have a Section 125 plan. You have an informal payroll practice, and informal payroll practices do not get tax-favored treatment. The IRS does not recognize unwritten arrangements.

Why the IRS Requires a Written Document

Section 125 of the Internal Revenue Code allows employees to choose between taxable and nontaxable benefits. That choice is called an election. The IRS permits the election only if it happens under a written plan that meets the requirements in Treasury Regulation 1.125-1.

The regulation is specific. The plan must be in writing. It must describe the benefits offered, the employees eligible to participate, the procedures for making elections, the rules for changing elections mid-year, and the plan year. The employer must adopt the plan before employees begin participating.

There is no grace period. There is no "we will get to it later." The document must exist and must be adopted before the first pre-tax deduction runs.

This is not an obscure technicality. This is the first requirement listed in the Treasury regulations. The IRS has been consistent on this point since Section 125 was enacted. A cafeteria plan without a written document is not a cafeteria plan.

What Must Be in the Document

The IRS lists the required elements in Treas. Reg. 1.125-1(c). Your premium-only plan document must include:

A description of the benefits offered. In a premium-only plan, this is straightforward: employer-sponsored health insurance premiums, and possibly dental and vision premiums. The document should name the benefit categories. It does not need to name the specific carriers or policy numbers—those change. It needs to make clear what types of premiums are eligible for pre-tax treatment.

Eligibility rules. Who can participate? Full-time employees only, or part-time as well? Is there a waiting period before new hires can enroll? The document must spell this out. The rules must apply uniformly to all employees in the same class.

Election procedures. When do employees make their election? Typically during open enrollment or within a set window after hire. How do they make the election—on paper, through a benefits portal, via the payroll system? The document must describe the process.

The plan year. Most premium-only plans run on a calendar year to align with the health insurance policy year. Some run on a different 12-month cycle. Either way, the document must state the plan year.

Rules for changing elections mid-year. Under Section 125, elections are locked in for the plan year unless the employee has a qualifying life event. The document must describe what counts as a qualifying event and what changes are permitted. For a premium-only plan, this typically mirrors the health plan's special enrollment rules.

The plan administrator. Someone must be named as the plan administrator. This is often the employer itself, or sometimes an officer or HR lead. The administrator is responsible for operating the plan according to its terms and ensuring compliance with IRS rules.

Your Section 125 plan document does not need to be long. A premium-only plan document can run four to six pages. But it must cover these elements. A one-paragraph summary on your intranet does not meet the requirement.

Why "We Just Do Pretax" Is Not Compliant

Many small employers believe that if their payroll provider is already deducting premiums on a pre-tax basis, the plan exists. It does not. The payroll configuration is not the plan. The plan is the written document that governs the payroll configuration.

Payroll systems can be set to treat any deduction as pre-tax. That setting does not create a Section 125 plan. It creates a pre-tax deduction. The IRS does not care what your payroll system does. The IRS cares whether you have a written plan that satisfies the regulatory requirements.

If you are audited and you cannot produce a written plan document, the IRS will reclassify the deductions as taxable. The employees will owe income tax and FICA on the amounts that were deducted pre-tax. The employer will owe the employer-side FICA on those amounts, plus penalties and interest. The audit lookback period can extend three years.

This happens. It is not theoretical. Employers who assume that "the broker set it up" or "payroll handles it" discover during an audit that no written document was ever created. The cost of fixing it retroactively is far higher than the cost of adopting a compliant document up front.

What Happens If You Skip the Document

If you are currently deducting premiums on a pre-tax basis and you do not have a written plan document, you are at risk. The immediate risk is an IRS audit. The secondary risk is a Department of Labor investigation, because cafeteria plans are also subject to ERISA reporting and disclosure rules. A plan without a document cannot comply with those rules either.

The typical consequence is retroactive reclassification. The IRS treats the deductions as if they were always taxable. The employer must issue corrected W-2s for prior years. Employees may owe additional tax. The employer owes back taxes, penalties, and interest on the employer share.

The less common but more painful consequence is plan disqualification. If the IRS determines that the arrangement never qualified as a Section 125 plan, the entire tax benefit is lost. Employees lose the pre-tax treatment permanently. The employer loses the payroll tax reduction. Fixing it requires starting over with a compliant document and treating everything going forward as a new plan.

There is no statute of limitations on a plan that was never valid to begin with. An unwritten plan is an invalid plan. The lookback can go as far back as the IRS wants to examine.

How to Get a Compliant Document

You do not need a benefits attorney to adopt a premium-only plan document, though you can hire one if you want certainty. Many payroll providers and benefits administration platforms offer template documents that meet the IRS requirements. Some charge for them. Some include them as part of the service.

If you use a template, read it. Make sure it reflects your actual eligibility rules, your plan year, and your election procedures. Do not adopt a document that describes a different plan than the one you are operating. The document and the practice must match.

The employer must formally adopt the plan. This typically means a board resolution or an officer signature on the adoption page. The adoption must happen before the plan year starts, or before employees begin participating if you are setting up the plan mid-year.

Once adopted, the document must be kept on file. You do not file it with the IRS. You do not send it to employees unless they ask for it. But you must be able to produce it if the IRS requests it during an audit. Keep a signed copy with your corporate records and give a copy to whoever administers the plan.

You must also provide a Summary Plan Description to participants. This is a shorter, plain-language summary of the plan's key terms. For a premium-only plan, this is often a one-page handout. ERISA requires it. The summary is not a substitute for the full plan document, but it is part of the compliance package.

Premium-only plans are also subject to nondiscrimination testing under Section 125. The testing ensures that the plan does not disproportionately benefit highly compensated employees. The testing is typically done annually, and the results must be documented. If your plan fails the testing, you must correct it or risk disqualification.

When You Need More Than a Premium-Only Plan

A premium-only plan covers insurance premiums only. If you want to offer a health FSA, a dependent care FSA, or other pre-tax benefits, you need a full cafeteria plan document, not just a premium-only plan document. The full plan document is longer and more complex, and the compliance obligations are heavier.

Many employers start with a premium-only plan and later expand to a full cafeteria plan. That is fine. You can amend the plan document to add benefits. But you cannot operate benefits that are not described in your written plan. If your document says premium-only and you are offering an FSA, you are out of compliance.

FAQ

Do I need a premium-only plan document if my payroll company handles everything?

Yes. The payroll company processes the deductions, but the employer must adopt and maintain the written plan document. The payroll company may provide a template, but adopting it is your responsibility. The IRS holds the employer accountable, not the vendor.

Can I adopt a plan document retroactively?

The IRS requires the document to be in place before the plan year begins or before employees start participating. Retroactive adoption does not cure the compliance failure for prior periods. If you discover you have been operating without a document, adopt one immediately to fix it going forward, but prior years remain at risk.

How often do I need to update the plan document?

You must update the document whenever the law changes in a way that affects plan operation, or whenever you change your plan's terms. IRS guidance updates, changes to your eligibility rules, and changes to your benefit offerings all require amendments. Many employers review and update the document annually as part of open enrollment.

Do employees need to sign the plan document?

No. Employees make an election to participate, typically through an enrollment form or online portal. They do not sign the plan document itself. The employer adopts the document. Employees receive a Summary Plan Description that explains the plan in plain language.

Running the Plan, Not Just Using It?

If you are the employer setting up or administering a premium-only plan, the Section 125 setup guide walks through the plan document, the adoption process, the payroll configuration, and the compliance steps that catch most people off guard—in plain English, with the IRS sources linked.