Week 15 Day 4: HSA: The Secret Best Retirement Account

If you have a High Deductible Health Plan (HDHP), you can contribute to an HSA: $4,150/year individual or $8,300/year family in 2024. The money goes in tax-free, grows tax-free, and comes out tax-free when used for medical expenses. After age 65, you can withdraw for any purpose (taxed like a 401(k)).

The power move with an HSA: do not use it for current medical expenses. Pay medical bills out of pocket (or with a credit card for points), save the receipts, and let the HSA money invest and grow. After decades of compounding, you can reimburse yourself for all those past medical expenses tax-free -- there is no time limit on claiming reimbursement. Or at 65, withdraw for any purpose with only income tax (no penalty). This turns the HSA into a super-powered retirement account. A family contributing $8,300/year for 20 years at 7% growth would have approximately $363,000 in the HSA. If withdrawn tax-free against accumulated medical receipts, that is $363,000 tax-free -- better after-tax than a Roth IRA (which uses after-tax contributions). The HSA is the only account that avoids tax at every stage: contribution, growth, and withdrawal.

The HSA's triple tax advantage makes it mathematically superior to every other account type. The after-tax future value comparison: for a dollar of pre-tax income with marginal rate t, the HSA retains $1 * (1+r)^n (no tax at any stage when used for qualified expenses). The 401(k) retains $1 * (1+r)^n * (1-t_ret). The Roth retains $(1-t) * (1+r)^n. At 22% tax rate and 7% for 30 years: HSA = $7.61 per dollar. 401(k) = $5.94. Roth = $5.94. The HSA beats both by 28%. The catch: HSA contribution limits are modest and require an HDHP. Fidelity's 2024 retiree healthcare cost estimate is $165,000 per person (or $330,000 per couple) over a 30-year retirement. This means most retirees will have ample qualified medical expenses to justify tax-free HSA withdrawals. The strategy of accumulating receipts and deferring reimbursement is explicitly permitted by IRS rules (there is no reimbursement deadline), though it requires careful record-keeping.