ACA Marketplace plans always run on a calendar year: January 1 through December 31. Deductibles, out-of-pocket maximums, and all cost-sharing accumulation reset to zero on January 1, regardless of when the member enrolled or how much they spent in the prior year.
This is different from employer-sponsored coverage, which can run on any 12-month cycle. An employer whose benefits renew on July 1 gives employees a July-to-June plan year. ACA Marketplace plans do not work that way. A client who enrolled in October via a SEP has the same December 31 end date as a client who enrolled during open enrollment the prior November.
Key Takeaways
- ACA Marketplace plans always run January 1 through December 31. No variation based on when enrollment happened.
- Deductibles and out-of-pocket maximums reset to zero on January 1 every year.
- SEP enrollees get a shorter deductible accumulation window than open enrollment enrollees.
- No deductible credit carries between plans at renewal or when switching mid-year.
- A hospital stay crossing December 31 splits costs across two plan years with two separate deductibles.
Why this matters at enrollment
The coverage effective date determines how much of the plan year a client actually uses. A client with coverage starting January 1 gets 12 months of deductible accumulation. A client with coverage starting November 1 gets two months before the deductible resets.
That does not mean mid-year enrollment is a bad deal. It means the deductible math changes based on when coverage starts. Clients with significant upcoming expenses may find it worth timing care to the start of the next plan year when they will have a full 12 months to meet the deductible.
| Scenario | Enrollment Date | Coverage Start | Deductible Window |
|---|---|---|---|
| Open enrollment, standard | Nov 15 | Jan 1 | 12 months (Jan 1 – Dec 31) Full deductible accumulation window |
| Open enrollment, December selection | Dec 15 | Jan 1 | 12 months (Jan 1 – Dec 31) Still a full window; coverage starts Jan 1 |
| SEP enrollment in April | Apr 10 | May 1 | 8 months (May 1 – Dec 31) Deductible resets Jan 1 regardless |
| SEP enrollment in October | Oct 15 | Nov 1 | 2 months (Nov 1 – Dec 31) Very short window before reset |
Illustrative scenarios. Actual effective dates depend on enrollment date, SEP type, and exchange processing timelines. Verify effective date with the exchange before scheduling care.
Deductible accumulation does not transfer between plans
When a client switches plans at open enrollment, whatever they accumulated toward their current plan's deductible does not follow them. The new plan starts at zero on January 1.
This matters most for clients who had significant medical events late in the year and were approaching or had met their deductible. If a client hit $4,000 of a $4,500 deductible in October and is considering switching plans, they should understand that the new plan resets at zero. Staying on the current plan means those last $500 in accumulated costs carry them to the in-network deductible for the remaining weeks of the year. Switching means starting over.
This is not necessarily a reason to stay on an expensive plan. The math depends on the December premium differential, whether the client has remaining procedures before year end, and the new plan's deductible structure. But it is a factor brokers should surface before a client finalizes a switch during open enrollment.
The year-end hospital stay scenario
A client admitted to the hospital on December 28 and discharged on January 4 has a single continuous stay that crosses two plan years. Services on December 28 through 31 are billed against the current year's deductible and out-of-pocket maximum. Services on January 1 through 4 are billed against the new year's deductible and out-of-pocket maximum, which has reset to zero.
Example: a client on a $2,000 deductible plan who has already met the deductible in December might expect the January portion of the stay to be covered at the coinsurance rate, since the deductible is satisfied. That is true for the December days. On January 1, the deductible resets. The January 1 through 4 services are applied first against the new year's $2,000 deductible.
This scenario is not common, but it is entirely predictable for clients with planned inpatient procedures or ongoing hospital stays near the end of December. Brokers who work with clients managing chronic conditions or recovering from surgery in late December should bring up the year-end boundary before the hospitalization date.
What changes with a new plan year
On January 1, the following reset simultaneously across all ACA Marketplace plans:
- Individual deductible
- Family deductible
- Individual out-of-pocket maximum
- Family out-of-pocket maximum
- Prescription drug accumulation (on plans where drug costs apply to the deductible)
Network composition, provider directories, formularies, and cost-sharing percentages may also change on January 1 if the carrier or CMS has updated the plan design for the new year. A plan with the same name and similar premium can have different cost-sharing structure in the new plan year. Brokers who carry clients into January on auto-renewal without reviewing the Summary of Benefits and Coverage for the new year may be sending those clients into a plan with changed coinsurance rates or a new formulary tier for a medication they depend on.
SEP enrollees and the short deductible window
A client who enrolls through a SEP in October typically has coverage effective November 1. That gives two months of deductible accumulation before December 31. The full 12-month window does not begin until the following January 1.
For clients who enrolled mid-year specifically because they had a qualifying life event and anticipated upcoming expenses, the short window affects how much cost-sharing they can expect to clear before the reset. A $3,000 deductible is harder to meet in two months than in 12. Clients who are managing ongoing treatment or have a planned procedure should hear this math at the time of SEP enrollment.
The opposite can also be true. A client who enrolls in October and has no anticipated expenses in November or December pays two months of premium with a full deductible they are unlikely to meet. They enter January with a fresh deductible accumulation window. That is not a problem for most clients, but it is a realistic picture of what the first two months of coverage look like.
FAQ
What is the ACA plan year and when does it run?
An ACA Marketplace plan year runs January 1 through December 31. Unlike employer-sponsored plans, which can run on any 12-month cycle tied to the employer's benefit renewal date, every ACA Marketplace plan issued through the FFM or a state exchange follows the calendar year. A client who enrolls in March via a SEP has the same plan year end date, December 31, as a client who enrolled during open enrollment the prior November. The enrollment date does not change when the plan year ends.
Does a deductible reset every year even if I just enrolled?
Yes. The deductible resets to zero on January 1 regardless of when enrollment began. A client who enrolled through a SEP in October, reached $800 toward a $1,500 deductible by December, and continued with the same plan into the new year starts over at $0 on January 1. The $800 accumulated in October through December does not carry into the new plan year. This is one of the most common misunderstandings among clients who enroll mid-year expecting prior accumulation to count.
What happens to the deductible if a client switches plans at open enrollment?
Nothing carries. If a client accumulated $2,000 toward a $3,000 deductible in the current plan year and switches to a different plan during open enrollment, the new plan starts with a fresh deductible on January 1. There is no portability mechanism for deductible credit between ACA plans. This matters most for clients who had significant claims late in the year and were close to meeting their deductible. Switching plans resets that progress. Brokers who identify high-accumulation clients in October or November can flag the trade-off before the client makes a renewal decision.
What happens if a client is hospitalized over the New Year?
A hospital stay that begins in late December and ends in January spans two plan years. Services rendered in December are applied to the current plan year's deductible and out-of-pocket maximum. Services rendered in January are applied to the new plan year's deductible and out-of-pocket maximum, which has reset to zero. If the client is on the same plan both years, they may effectively pay two sets of cost-sharing for a single continuous stay. The hospital bills by date of service, not by admission date, so the split is line-by-line across the December 31 boundary. Clients with planned procedures or ongoing inpatient stays near year-end benefit from understanding this before the admission date.
Does a SEP enrollment in October give a full year of coverage before the deductible resets?
No. A client who enrolls via SEP in October typically has coverage effective November 1. That gives two months of deductible accumulation, November and December, before the plan year ends December 31 and the deductible resets. The client then has a full 12-month accumulation window starting January 1 of the following year, but the first two months of coverage are on a very short window. This is worth explaining at the time of SEP enrollment, particularly for clients with ongoing treatment or upcoming procedures. A client who knows the deductible will reset in January can time elective care accordingly.
