What Is an HSA ER Contribution? Limits, Taxes, and Deadlines

An HSA ER contribution is money your employer deposits into your Health Savings Account, shown on your pay stub as “ER” for employer. You owe no federal income tax on it, the money is yours to keep the moment it lands in the account, and it counts against the same IRS annual limit that applies to your own contributions. For 2026, that combined ceiling is $4,400 for self-only HDHP coverage and $8,750 for family coverage.¹

Your employer is not required to contribute anything. Many do, either through a Section 125 cafeteria plan that runs deposits each pay period or as standalone contributions outside a cafeteria plan.

How Employer Deposits Count Against Your Annual Limit

Internal Revenue Code Section 223 sets a single annual cap on all deposits into your HSA from every source combined: your own money, your employer’s money, and anyone else’s.² For 2026 the limits are $4,400 (self-only) and $8,750 (family). If you are 55 or older by the end of the tax year, you can add a $1,000 catch-up contribution, which brings the effective ceiling to $5,400 or $9,750. That $1,000 has been fixed since 2009 and does not adjust for inflation.

Every dollar your employer puts in reduces the room you have left. If your employer contributes $2,000 to your family-coverage HSA, you can contribute up to $6,750 on your own for 2026. When you calculate your personal limit, include the employer amount, including anything that runs through a cafeteria plan.³

Going over the cap is expensive. Excess contributions from any source trigger a 6 percent excise tax for each year the extra amount stays in the account.⁴ You can avoid it by pulling out the excess (plus any earnings on it) before your tax return due date, including extensions. Report the earnings as income for that year; the excess itself is not taxed again.⁵

Tax Treatment and What Shows on Your W-2

Under Section 106(d), employer HSA contributions are excluded from your gross income, so no federal income tax applies to those deposits.⁶ They are also generally exempt from Social Security and Medicare (FICA) taxes. You receive the full contribution with no payroll tax withheld, and your employer avoids the matching FICA it would otherwise owe on that amount.⁵

Money you contribute yourself through payroll deduction under a cafeteria plan gets the same treatment: it comes out before income and FICA taxes are calculated. If you write a personal check directly to the HSA custodian instead, you can deduct the amount on your tax return, but you will not escape FICA on that money.

Your employer reports the full total, both its own deposits and any salary-reduction amounts you elected through a cafeteria plan, in Box 12 of your Form W-2 using code W.⁵ That figure is not included in taxable wages (Boxes 1, 3, or 5), but it shows on the form so you and the IRS can track how much of the annual limit has been used. Check the Box 12 code W amount each year and compare it against the cap before adding any personal contributions on top.

The Money Is Yours Immediately

HSA balances vest instantly. Once your employer makes the deposit, the money is nonforfeitable, and your employer cannot take it back.⁵ Leave the company, switch to a non-HDHP, or retire, and you keep every dollar. You can use the funds for qualified medical expenses whether you still work there or not.

There is one narrow exception. If a clear administrative error occurs (an extra digit, a duplicate payroll file, a deposit credited to the wrong employee), the HSA custodian can return the mistaken amount to the employer when there is documented evidence and the correction puts both parties back where they started. A change of mind after a voluntary contribution does not qualify.

Eligibility You Must Maintain

To receive an employer HSA contribution for a given month, you have to be an “eligible individual” as the IRS defines it on the first day of that month:

You are enrolled in a qualifying High Deductible Health Plan.
You have no disqualifying other health coverage. A general-purpose Flexible Spending Account or Health Reimbursement Arrangement counts as disqualifying; a limited-purpose FSA restricted to dental and vision, standalone dental or vision plans, disability insurance, and long-term care coverage do not.²
You are not enrolled in any part of Medicare. If you are 65 or older and have delayed Medicare enrollment while staying on an HDHP, employer contributions can continue.⁷
You are not claimed as a dependent on someone else’s tax return.

Lose eligibility mid-year, and your annual limit is prorated to the months you did qualify. Employer contributions that push you above that prorated limit become excess contributions.

Deadline for Employer Contributions

An employer can make HSA contributions for a tax year up until the employee’s tax filing deadline, generally April 15 of the following year. A 2026 contribution can arrive as late as April 15, 2027. Most employers deposit each pay period, but the IRS does not require any particular schedule as long as the deadline is met and the annual cap is respected.²

When Comparability Rules Apply

If your employer contributes to HSAs outside a Section 125 cafeteria plan, Internal Revenue Code Section 4980G requires it to give either the same flat dollar amount or the same percentage of the HDHP deductible to each comparable group of employees. Groups are split into full-time workers, part-time workers (generally fewer than 30 hours per week), and former employees still on the company HDHP, and then further split by self-only versus family coverage. Within each subgroup, the contribution must be equal.⁸ Violations trigger an excise tax equal to 35 percent of the employer’s total HSA contributions for the calendar year.

Comparability does not apply when contributions run through a Section 125 cafeteria plan, which is how most employers handle HSA funding.⁹ If your employer uses a cafeteria plan, this rule likely never touches you.

The Last-Month Rule for Mid-Year Starters

Become eligible partway through the year, and your limit is normally prorated. The last-month rule offers an alternative: if you are an eligible individual on December 1, you can contribute the full annual amount as if you had been eligible for all 12 months.⁵

The catch is a 13-month testing period running from December 1 through December 31 of the following year. Stay eligible the whole time or the amount you contributed above your prorated limit becomes taxable income, plus an additional 10 percent tax. This applies to employer contributions too, so if you plan to use the last-month rule, coordinate with your employer before letting deposits run to the full annual cap.

1
Internal Revenue Service. IRS Notice 2026-05 – HSA Inflation Adjusted Amounts
2
Office of the Law Revision Counsel. 26 USC 223 – Health Savings Accounts
3
Internal Revenue Service. HSA Contributions
4
Office of the Law Revision Counsel. 26 USC 4973 – Tax on Excess Contributions to Certain Tax-Favored Accounts and Annuities
5
Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans
6
Office of the Law Revision Counsel. 26 USC 106 – Contributions by Employer to Accident and Health Plans
7
Internal Revenue Service. Individuals Who Qualify for an HSA
8
Office of the Law Revision Counsel. 26 USC 4980G – Failure of Employer to Make Comparable Health Savings Account Contributions
9
eCFR. 26 CFR 54.4980G-5 – HSA Comparability Rules and Cafeteria Plans and Waiver of Excise Tax