Section 125 Plan Document: What It Must Include and Why Payroll Cannot Replace It

• Proposed Treasury Regulation Section 1.125-1(c)(1) lists six items every Section 125 plan document must contain, plus extra terms when the plan offers FSAs, a grace period, paid time off or HSA distributions.
• A Section 125 plan document must be adopted and effective on or before the first day of the plan year, and amendments only apply to periods after they are adopted (Prop. Treas. Reg. 1.125-1(c)(5)).
• Without a written Section 125 plan document, the IRS treats every pre-tax deduction as taxable income to the employee (Prop. Treas. Reg. 1.125-1(c)(6)).
• The 2026 health FSA salary reduction limit is $3,400 with a $680 carryover, per IRS Revenue Procedure 2025-32, and the plan document should state the limit the employer actually uses.
• IRS Notice 2002-24 removed the Form 5500 filing requirement for the cafeteria plan itself, but the Section 125 plan document is still required.

Many employers learn about the Section 125 plan document the hard way. Payroll turns on pre-tax deductions, the savings show up on the next Form 941, and nobody asks where the written plan is until an auditor, a broker or a new CFO does. This guide explains exactly what the Section 125 plan document must say, when it must be signed and how to tell whether yours is complete.

What is a Section 125 plan document?

A Section 125 plan document is the legal, written cafeteria plan that allows employees to choose between taxable cash wages and pre-tax benefits such as health insurance premiums, a health FSA or dependent care assistance. Internal Revenue Code Section 125 creates the tax break, and Proposed Treasury Regulation Section 1.125-1(c) says the break only exists when a written plan does. The Section 125 plan document is signed by the employer, sets the rules for the plan year and controls how payroll must treat every pre-tax deduction. The Section 125 plan document can be one document or several documents read together, so long as all required terms appear somewhere in writing. A payroll system setting, a benefits guide or an insurance carrier contract is not a Section 125 plan document by itself. Those items carry out the plan. The written plan is what makes the deductions legally pre-tax.

What must a Section 125 plan document include?

A Section 125 plan document must contain six core items under Proposed Treasury Regulation Section 1.125-1(c)(1). Each item has to be specific enough that an employee or the IRS could read the Section 125 plan document and know who can join, what they can buy pre-tax and when they can change their minds. The terms of the plan must also apply uniformly to all participants. Missing any one of these six items means the written plan does not satisfy the regulation, and Proposed Treasury Regulation Section 1.125-1(c)(6) says a plan that fails the written plan requirements is not a cafeteria plan. The checklist below follows the order used in the regulation, so an employer or broker can compare it line by line against the plan document already on file.

1. A specific description of each benefit offered through the plan, including the period of coverage for each benefit.
2. The rules for participation, including a statement that all participants must be employees.
3. The election procedures, including when elections are made, the period each election covers, and a statement that elections are irrevocable except for permitted changes in status under Treas. Reg. 1.125-4.
4. How employer contributions are made, such as employee salary reduction, employer flex credits or both.
5. The maximum contribution available to any employee, stated as a dollar amount, a percentage of pay or a method for setting the maximum.
6. The plan year of the cafeteria plan.

What extra terms apply to FSAs, dependent care and other benefits?

A Section 125 plan document needs extra terms when the cafeteria plan offers flexible spending accounts, a grace period, paid time off or health FSA distributions to HSAs, according to Proposed Treasury Regulation Section 1.125-1(c)(1)(vii) through (x). A flexible spending account, or FSA, is an account employees fund with pre-tax pay to cover eligible medical or dependent care costs. For a health FSA, the Section 125 plan document must include the uniform coverage rule, which makes the full annual election available from the first day, and the use-or-lose rule, which forfeits unused balances unless a carryover or grace period applies. The document must also state the maximum election. For plan years beginning in 2026, IRS Revenue Procedure 2025-32 caps health FSA salary reductions at $3,400 and the carryover at $680. A plan can set a lower maximum, but the Section 125 plan document has to state the number the plan uses.

Dependent care assistance needs its own written program under Internal Revenue Code Section 129(d)(1). The Section 125 plan document can include those terms or point to a separate written plan. Benecor's guide to the 2026 dependent care FSA limit→ covers the new annual cap, and the 2026 FSA contribution limits guide→ covers the health FSA numbers.

The Section 125 plan document can also incorporate other written plans by reference, such as a group health policy or a 401(k) plan, under Proposed Treasury Regulation Section 1.125-1(c)(4). The cross-reference has to be clear enough that a reader can find the benefit terms.

When must a Section 125 plan document be signed?

A Section 125 plan document must be adopted and effective on or before the first day of the plan year it covers, under Proposed Treasury Regulation Section 1.125-1(c)(1). An employer starting a calendar-year plan on January 1 needs the Section 125 plan document signed by January 1, not in March after payroll has already taken pre-tax deductions. A new plan can start mid-year, but it can only cover deductions and expenses from its effective date forward. Amendments follow the same rule. Proposed Treasury Regulation Section 1.125-1(c)(5) says any amendment must be in writing and can only take effect for periods after the later of its adoption date or effective date. That means a Section 125 plan document cannot be backdated to fix deductions payroll took before the plan existed. Employers should also keep the signed document, every amendment and each year's election forms together, because those records are what an IRS examiner asks for first.

A practical setup timeline for a new Section 125 plan document looks like this:

1. Choose the plan year and benefits. Decide whether the plan covers premiums only or adds a health FSA or dependent care FSA.
2. Draft or adopt the document. Use a custom plan or a prototype plan with an adoption agreement.
3. Sign before the effective date. An owner or officer signs and dates the Section 125 plan document.
4. Collect employee elections. Every participant completes an election form before deductions start.
5. Configure payroll. Payroll codes pre-tax deductions to match the elections and the plan terms.
6. Test and file away. Run nondiscrimination testing and store the plan, amendments and elections together.

What happens if a Section 125 plan document is missing or incomplete?

When a Section 125 plan document is missing or incomplete, the IRS treats the arrangement as if no cafeteria plan exists, under Proposed Treasury Regulation Section 1.125-1(c)(6). Every dollar employees elected pre-tax becomes taxable wages. The employer then owes the 7.65% employer share of FICA it skipped, is liable for the employee FICA and income tax it failed to withhold, and faces IRS failure-to-deposit penalties of 2% to 15% under Internal Revenue Code Section 6656, plus interest. Employees can owe more income tax on their own returns too. The damage grows with each year the problem goes unnoticed, because the taxes stack up across every quarter. A plan that has a complete Section 125 plan document but does not follow it faces the same result under the operational failure rule in Proposed Treasury Regulation Section 1.125-1(c)(7), such as letting employees stop deductions mid-year without a permitted change in status.

This is a hypothetical example using the 7.65% FICA rate set by Internal Revenue Code Sections 3101 and 3111. Actual amounts depend on wages, elections and state tax rules.

Is a Section 125 plan document the same as an SPD?

A Section 125 plan document is not the same as a summary plan description, or SPD. The Section 125 plan document is an IRS requirement that creates the cafeteria plan and its tax rules. An SPD is an ERISA requirement that explains ERISA-covered welfare benefits, such as group health coverage or a health FSA, to participants in plain language. ERISA Section 104(b) requires the plan administrator to give participants the SPD, and ERISA Section 502(c)(1) lets a court impose up to $110 per day when a requested plan document is not provided, per 29 CFR 2575.502c-1. Many employers use one combined document that serves as both the Section 125 plan document and the SPD, which is allowed so long as both sets of requirements are met. What an employer cannot do is hand out an insurance carrier's benefit summary and assume it covers either requirement, because a carrier summary does not describe the cafeteria plan's election rules.

Does a Section 125 plan document need to be filed with the IRS?

A Section 125 plan document does not get filed with the IRS or the Department of Labor. The employer keeps the signed Section 125 plan document on file and produces it when asked by the IRS, an auditor or a participant. IRS Notice 2002-24 also suspended the old requirement for cafeteria plans to file Form 5500 with Schedule F, so the cafeteria plan itself has no annual return. Benefits offered through the plan can still carry their own filing duties. A health plan or health FSA that is an ERISA welfare plan generally files Form 5500 once it covers 100 or more participants at the start of the plan year, or when it is funded through a trust. The Department of Labor can assess up to $2,739 per day for a late Form 5500, an amount the Department of Labor did not increase for 2026. Keeping the Section 125 plan document current is the step that protects the tax break itself.

How do nondiscrimination rules connect to the plan document?

The Section 125 plan document sets eligibility and benefit terms, and Internal Revenue Code Section 125(b) tests whether those terms favor highly compensated or key employees. A highly compensated employee for 2026 plan purposes generally earned more than $160,000 in 2025, per IRS Notice 2025-67. If the plan fails the eligibility or benefits tests, highly compensated participants lose their tax exclusion. If key employees receive more than 25% of total qualified benefits under the plan, the key employees' benefits become taxable. Rank-and-file employees keep their pre-tax treatment either way. A well-drafted Section 125 plan document helps by setting uniform eligibility rules, a uniform waiting period and the same contribution options for every class of employee. Benecor's Section 125 nondiscrimination testing guide→ explains each test, and the highly compensated employee definition→ guide shows who counts.

Who provides the Section 125 plan document?

A Section 125 plan document is usually provided by a plan administrator, a benefits attorney or a third-party administrator, not by the payroll company or the insurance carrier. Payroll providers apply the deductions, and carriers supply the insurance policy, but neither one writes the cafeteria plan that makes those deductions pre-tax. Some employers buy a template and fill it in themselves. That can work for a simple premium-only plan, but the employer still has to keep the Section 125 plan document updated as benefits, limits and eligibility change each year.

Benecor Health sets up Section 125 cafeteria plans for W-2 employers and handles the written plan as part of that setup, alongside employee enrollment and payroll coordination. Benecor's Section 125 cafeteria plan guide→ explains how the full plan works, and the Section 125 plan cost→ page shows what employers pay and save. If you already have a plan in place, a Benecor benefits expert can review whether the Section 125 plan document on file matches what payroll is doing today.

Sources: Proposed Treasury Regulation Sections 1.125-1(c), 1.125-1(e), 1.125-1(o) and 1.125-5, Employee Benefits: Cafeteria Plans, Federal Register (August 6, 2007); Treasury Regulation Section 1.125-4 (permitted election changes); Internal Revenue Code Sections 125(b), 129(d)(1), 3101, 3111 and 6656; IRS Revenue Procedure 2025-32 (2026 health FSA limit of $3,400 and $680 carryover); IRS Notice 2025-67 (2026 highly compensated employee threshold); IRS Notice 2002-24 (suspension of Form 5500 Schedule F for cafeteria plans); IRS, Failure to Deposit Penalty (2025); ERISA Sections 104(b) and 502(c)(1); 29 CFR 2575.502c-1; U.S. Department of Labor, Adjusting ERISA Civil Monetary Penalties for Inflation (2026 amounts unchanged from 2025).