These are not competing products you pick between. Medicare is age-based or disability-based federal coverage; the ACA marketplace is where people under 65 buy their own. Almost nobody gets a real choice — but the handoff between them has deadlines, and missing one is expensive.
Who is eligible for which
- Medicare at 65, or earlier after 24 months of Social Security disability benefits, or immediately with ALS or end-stage renal disease.
- The marketplace for anyone lawfully present who is not enrolled in Medicare. Premium tax credits are generally unavailable once you are eligible for premium-free Part A, which is why keeping a subsidized marketplace plan past 65 does not work.
The handoff at 65
Your Initial Enrollment Period runs seven months: the three months before the month you turn 65, that month, and the three months after. Enrolling in the first three means coverage starts the month you turn 65. Miss the window without other qualifying coverage and Part B carries a late-enrollment penalty of 10% for each full year you delayed — permanently, for as long as you have Part B.
Tell the marketplace when your Medicare starts and end the marketplace plan deliberately. Leaving it running means paying for coverage that has stopped doing you much good, and any premium tax credit you take after you are eligible for Medicare can be clawed back at tax time.
When one spouse turns 65 first
This is the case that catches people. Medicare covers one person, never a couple. The younger spouse stays on a marketplace plan, and their subsidy is recalculated on a household of one fewer enrollee — the household income still counts, so the change is rarely neutral. Re-run the numbers rather than assuming the existing plan still makes sense.
Under 65 and waiting
If you retired early, the marketplace is where you live until 65, and managing your projected income is the single biggest lever on what you pay. See health insurance for retirees under 65 for how that works.
Health Advisory does not sell Medicare. If you are 65 or turning 65, go to Medicare.gov or your State Health Insurance Assistance Program, which gives free unbiased counseling. If you are under 65 — including the younger half of a couple — enter your ZIP code below and a licensed agent will run the marketplace side for you, or call (713) 575-9904.