Health Savings Account (HSA): Definition and How It Works

A Health Savings Account (HSA) is a tax-advantaged savings account available to individuals enrolled in a High Deductible Health Plan (HDHP) that allows them to set aside pre-tax money to pay for current and future qualified medical expenses. Under IRC §223, HSAs offer a triple-tax advantage: (1) contributions are deductible (or pre-tax if made through payroll); (2) investment earnings inside the account grow tax-free; and (3) distributions used for qualified medical expenses are tax-free. No other savings vehicle in the tax code offers this combination. For insurance brokers and benefits advisors, HSAs are central to the HDHP strategy and are frequently paired with employer-sponsored group health plans as a cost-sharing and tax-planning tool.

HSA Eligibility Requirements

Not everyone can contribute to an HSA. The rules under IRC §223 require:

• Enrollment in an HDHP: The individual must be covered by an HSA-eligible High Deductible Health Plan for every month in which they make (or receive) HSA contributions. An HDHP for 2026 must have a minimum deductible of $1,650 (self-only) or $3,300 (family) and a maximum out-of-pocket limit of $8,300 (self-only) or $16,600 (family).
• No other disqualifying coverage: The individual cannot be covered by a non-HDHP health plan, Medicare, or Medicaid. They also cannot be claimed as a dependent on another person's tax return.
• Not enrolled in Medicare: Once a taxpayer enrolls in Medicare Part A or B, HSA contributions are prohibited — even if they remain in an HDHP through a spouse's employer plan.

2026 Contribution Limits

(Source: IRS Rev. Proc. 2025-19; limits are inflation-adjusted annually.)

Contributions may be made by the account holder, a family member, or an employer. Total contributions from all sources cannot exceed the annual limit. Employer contributions are excluded from the employee's gross income and are not subject to FICA.

The Triple Tax Advantage

1. Tax-free contributions: Contributions made directly to an HSA by the account holder are deductible above-the-line under IRC §223, reducing AGI regardless of whether the taxpayer itemizes deductions. Payroll contributions — where the employer routes employee funds to the HSA pre-tax — bypass both income tax and FICA tax, making the tax benefit even larger.

2. Tax-free growth: Investment earnings (interest, dividends, capital gains) inside the HSA accumulate tax-free. Many HSA custodians allow account holders to invest funds in mutual funds or ETFs once the balance exceeds a threshold (typically $1,000–$2,000). Long-term investors can allow HSA balances to compound for decades.

3. Tax-free withdrawals for qualified expenses: Distributions used for qualified medical expenses (as defined by IRC §213) are entirely tax-free — no income tax, no penalty. Qualified expenses include physician visits, prescription drugs, dental and vision care, mental health services, and certain long-term care premiums. This list is broad; IRS Publication 502 is the authoritative reference.

After age 65: Once the account holder reaches age 65, distributions for non-medical expenses are taxed as ordinary income but are not subject to penalty — making the HSA function like a Traditional IRA for non-medical purposes. This dual functionality makes HSAs particularly valuable as retirement savings vehicles for clients who expect high medical costs in retirement.

HSA vs HRA vs FSA

For a complete comparison including 2025 contribution limits and use-case analysis, see HRA vs HSA vs FSA: How Each Account Works.

HSA as a Long-Term Savings Strategy

The optimal HSA strategy — for high-income clients with adequate cash flow — is to pay current medical expenses out of pocket and allow the HSA balance to grow invested for decades. Because there is no deadline for reimbursing past medical expenses from an HSA, a client can accumulate receipts for years of out-of-pocket medical spending and then take a large tax-free distribution at any point in the future. This "HSA banking" strategy effectively converts the HSA into a powerful tax-free account for high earners who don't need to tap it for current expenses.

Employer HSA Contributions and ERISA

When employers contribute to employee HSAs, those contributions must comply with the comparability rules under IRC §4980G — contributions must be comparable (same dollar amount or same percentage of deductible) for all eligible employees within the same category. Health FSA contributions are subject to ERISA; HSAs themselves are not ERISA plans, but employer-sponsored payroll contribution programs may have ERISA implications depending on how they are structured. Benefits brokers should ensure HR clients understand the distinction before designing their HDHP + HSA offering.

Related Terms

• Adjusted Gross Income — HSA contributions reduce AGI above-the-line, creating a compounding benefit that may preserve eligibility for other AGI-sensitive provisions
• Pass-Through Entity — self-employed business owners can establish and contribute to their own HSA independent of any employer plan, as long as they are enrolled in an HDHP

How Benefits Brokers and CPAs Use HSAs in Practice

Benefits brokers use HSAs as a core component of HDHP plan design, helping employers shift from fully-insured to HDHP structures while using employer HSA contributions to offset the higher employee deductible burden. CPAs advise high-income clients to maximize HSA contributions as one of the few remaining above-the-line deductions available to individuals not covered by a workplace retirement plan. For individual coverage HRA (ICHRA) mechanics — which allow employers to reimburse employees for individual health coverage costs including HSA-eligible HDHPs — see ICHRA: How to Evaluate and Implement an Individual Coverage HRA.