If you have read anywhere that the Marketplace window now shuts on 15 December, you have read something that was true as a plan and never became true as a deadline. It is worth being precise about, because the error cuts the wrong way: someone who believes it and misses 15 December may conclude they are locked out for the year, when in fact they have another month.
For 2027 coverage on the federal platform, open enrollment runs 1 November 2026 to 15 January 2027.
What happened to the shorter window
The 2025 Marketplace Integrity and Affordability Final Rule did shorten it. Beginning with plan year 2027, the federal window was to run from 1 November to 15 December, and state Exchanges were to be capped at nine calendar weeks ending no later than 31 December.
That did not survive. On 12 June 2026, in City of Columbus v. Kennedy, the US District Court for the District of Maryland issued an order striking certain provisions of the rule. A second order on 16 July 2026 stayed provisions of the Notice of Benefit and Payment Parameters for 2027.
CMS set out the consequence in a statement dated 27 July 2026:
Open Enrollment at the Federally-facilitated Marketplace will begin on November 1, 2026 and end on January 15, 2027.
The same statement says HHS "has not altered the dates for the Open Enrollment period contained in 45 CFR 155.410(e)(4), including related flexibilities available to State Exchanges."
So the window people are used to is the window that applies. The nine-week cap and the 31 December backstop went with the struck provisions.
One caveat worth carrying: the codified regulation text has not been conformed to the ruling everywhere, and a good deal of secondary guidance — including some written for insurance agents — still quotes 15 December. If you find a December date, check its publication date against June 2026 before you act on it.
The date that still matters: 15 December
Dropping the shorter window does not make 15 December meaningless. It restores its older job, which is to set when coverage begins. HealthCare.gov puts it as two deadlines rather than one:
| If you enroll | Coverage starts |
|---|---|
| 1 November to 15 December 2026 | 1 January 2027 |
| 16 December 2026 to 15 January 2027 | 1 February 2027 |
That is the practical shape of the window. The last day to enroll is 15 January. The last day to enroll and be covered from the first of the year is 15 December. Missing the first costs a month of cover; missing the second costs the year.
Which means the advice that follows from the old, incorrect version of this article survives intact, for a different reason: treat 15 December as your deadline. Not because the window shuts, but because a January gap in cover is a real thing that happens to people who wait.
If your state runs its own Exchange
Roughly a third of enrollees are not on the federal platform, and CMS has confirmed that the State Exchange flexibilities at 45 CFR 155.410(e)(4) were not altered. A state running its own Exchange can therefore set dates of its own.
| Marketplace type | What it means for your deadline | Where |
|---|---|---|
| Federally-facilitated (FFM) | 1 November to 15 January | Alabama, Alaska, Arizona, Delaware, Florida, Hawaii, Indiana, Iowa, Kansas, Louisiana, Michigan, Mississippi, Missouri, Montana, Nebraska, New Hampshire, North Carolina, North Dakota, Ohio, South Carolina, South Dakota, Tennessee, Texas, Utah, West Virginia, Wisconsin, Wyoming |
| State-based on the federal platform (SBM-FP) | Enrols through HealthCare.gov, on the federal dates | Arkansas, Oklahoma |
| State-based (SBM) | May set its own dates — check the Exchange | California, Colorado, Connecticut, District of Columbia, Georgia, Idaho, Illinois, Kentucky, Maine, Maryland, Massachusetts, Minnesota, Nevada, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont, Virginia, Washington |
Only the last group has room to differ, and that is 21 states plus the District of Columbia. This article does not list state-by-state dates, because each Exchange sets and announces its own. If you are in one of them, the date your Exchange publishes is the one that governs.
What to do with the time you have
The window is the length people remember, which makes it easy to drift. Three things are worth doing before 15 December rather than after.
Read what your current plan is doing next year. Premiums, deductibles, provider networks and drug formularies all change annually. A plan with the same name in January is not necessarily the same plan.
Check the plan against the numbers, not the premium. The 2027 out-of-pocket maximum is $12,000 for self-only coverage and $24,000 for other than self-only. That ceiling, the deductible and how the plan treats out-of-network care matter more than the monthly figure: the full picture is in how the four layers of health plan cost actually work.
If your income is modest, look at silver specifically. Cost-sharing reductions attach only to silver plans, and choosing bronze for a cheaper premium forfeits them. That is the single most expensive mistake available during open enrollment, and it is covered in the same guide. Income matters a second way: premium tax credits now stop completely above 400% of the federal poverty line rather than tapering, so the figure you estimate on the application is worth getting right. What happens at that line is set out separately.
If you miss it
Missing open enrollment generally means waiting for the next one. The exception is a special enrollment period, opened by a life event: losing other coverage, moving, marriage, a birth or adoption among them. These have their own deadlines, usually measured in days from the event rather than months.
Relying on one is not a plan. It is what exists if the plan fails.
If you are approaching 65, this is not the deadline that applies to you. Medicare runs its own enrollment period on a different timetable, from 15 October to 7 December, and what to check during it is a separate question with separate consequences.
Before 15 December
- Which Exchange are you on? Federal platform means 1 November to 15 January. A state Exchange may differ: check the date your state publishes.
- Are you working to 15 December or 15 January? Enroll by 15 December if you want cover from 1 January.
- Has your plan sent notice of changes for next year? Read it rather than filing it.
- What is the deductible and the out-of-pocket maximum, not just the premium?
- Would cost-sharing reductions apply to you? If so, silver is the only tier that carries them.
This article sets out the enrollment dates and rules published by CMS and HealthCare.gov. It is not insurance or financial advice, and what plan suits you depends on your income, your household and the care you expect to need. The litigation behind these dates is not finished and CMS has said it will issue further guidance as needed, so confirm the date on HealthCare.gov or your state Exchange before relying on it.
Sources
- CMS: Updated Statement regarding the Failure to File and Reconcile requirement for Plan Years 2026-2027 (27 July 2026) (opens in a new tab)
- HealthCare.gov: When can you get health insurance? Dates and deadlines (opens in a new tab)
- CMS: 2025 Marketplace Integrity and Affordability Final Rule (opens in a new tab)
- CMS: States by Marketplace Type (FFM/SBM-FP/SBM) for Plan Year 2027 (opens in a new tab)
- HealthCare.gov: Renew, change, update, or cancel your plan (opens in a new tab)
- HealthCare.gov: Special enrollment periods (opens in a new tab)
This article is general information for a United States audience and reflects the enrollment dates published by CMS and HealthCare.gov at the date of review. It is not insurance, tax or financial advice. The dates arise from live litigation and can change, and state-run Exchanges set their own windows. Confirm the deadline that applies to you on HealthCare.gov or your state Exchange before relying on any of this. Last reviewed 23 October 2026.
