The HSA — the most tax-efficient retirement account most people ignore.
Three different tax breaks in one account. No income limits. Contribution dollars grow tax-free forever, can be invested, and come out tax-free for qualified medical expenses. After 65, they function like a traditional IRA — but for healthcare costs, which are often the largest unfunded liability in retirement.
The Health Savings Account is the only retirement vehicle in the U.S. tax code with a triple tax advantage: pre-tax dollars going in, tax-free growth, and tax-free withdrawals for qualified medical expenses. No 401(k), no IRA, no Roth touches that. And most eligible savers either ignore it, or use it as a year-to-year flex spending account instead of a retirement asset.
Who's eligible
You must be enrolled in a High Deductible Health Plan (HDHP) and not enrolled in any other non-HDHP coverage, including Medicare. Most working-age people in plans with deductibles above roughly $1,650 single / $3,300 family qualify; check the IRS limits each year. Once you enroll in Medicare (even just Part A), you can no longer contribute — though existing balances stay yours forever.
The contribution math
For 2026 the limits are roughly $4,400 single / $8,750 family with a $1,000 catch-up at 55+. If you and your spouse are both 55+ and both on HDHPs, you can each have your own HSA with a catch-up contribution. Maxing for ten or fifteen years and investing the balance can easily produce a six-figure account by Medicare eligibility.
The retirement-account math
The key move is not spending out of the HSA for current medical expenses if you can afford to cash-flow them. Save receipts. Let the HSA grow. In retirement, you can reimburse yourself for old qualified expenses (no statute of limitations on receipts) — pulling the money out tax-free, decades after you spent it. This is the closest thing to a Roth on steroids the tax code offers.
After 65 the rules soften
At 65, non-medical HSA withdrawals become subject only to ordinary income tax — no 20% penalty. That means the worst case for a 65+ HSA holder is that the account behaves exactly like a traditional IRA. Qualified medical expenses still come out tax-free. Long-term care premiums up to age-based limits are qualified. Even Medicare Part B and Part D premiums are qualified.
Investment choices matter
Many HSA custodians default to a low-yield savings account inside the HSA. Look for a custodian that offers investment options once your balance crosses a small threshold (often $1,000–$2,000). The HSAs sitting in zero-percent cash accounts are the saddest retirement opportunity cost in personal finance.
The stop-contributing-six-months-before-Medicare trap
Medicare Part A enrollment is retroactive by up to six months when you sign up after 65. If you contribute to an HSA in those retroactive months, you've created a penalty. Plan to stop HSA contributions at least six months before you enroll in Medicare, or before your 65th birthday if you're enrolling on time.
For Texas-based clients
Texas has no state income tax, so the HSA's federal-only deduction is the entire deduction available — same as for any pre-tax retirement contribution. The relative benefit compared to a state-tax state is identical (it's just that the savings show up only on the federal return).
For most clients, the HSA is the last account I'd want to spend down. It's the first account I'd want to fund.