The exchange is a marketplace, not an insurer
The confusion is built into the name. An exchange sounds like a company you buy insurance from; it is not. It is the regulated marketplace where private insurers sell Affordable Care Act plans, under rules that standardise what the plans must cover and how they may be sold. You compare plans on the exchange, apply there, and buy there — but once you have bought, you view and manage your cover with the insurance company you chose, not with the exchange.
That distinction matters when something goes wrong. A denied claim is the insurer's decision, appealed through the insurer. A problem with the application, the subsidy or the enrollment itself is the exchange's. Knowing which door to knock on saves a round of being passed between the two.
Federal or state-based: which one you use
Every state has an exchange, but not every state runs its own. Most states use the federal marketplace, HealthCare.gov, run by the Centers for Medicare & Medicaid Services. For the 2026 coverage year, 20 states and Washington, D.C. run their own marketplaces instead, and 30 states use HealthCare.gov. Two more states run state-based exchanges that use the federal platform for eligibility and enrollment.
The state-run marketplaces have their own names — Covered California in California, Pennie in Pennsylvania, Washington Healthplanfinder in Washington, Get Covered Illinois in Illinois, BeWell in New Mexico — and their own call centres. If you enter your ZIP code on HealthCare.gov for one of those states, the site directs you to the right state marketplace. The practical differences are deadlines and customer service: state-run exchanges sometimes set their own enrollment periods, sometimes extend deadlines beyond the federal schedule, and may offer additional state financial help. The federal floor of consumer protections and benefit requirements is the same on either route.
What every marketplace plan covers
Plans sold on an exchange are called qualified health plans. All of them must cover the essential health benefits — the ACA's list of ten benefit categories, including hospital care, prescription drugs, maternity care, mental health and substance-use treatment, and preventive services. They cannot deny you enrollment for a pre-existing condition, and they cannot charge you more because of one.
Plans are sorted into metal tiers that describe how costs are split between you and the insurer: bronze, silver, gold and platinum. Bronze plans have the lowest monthly premium and the highest costs when you use care; platinum is the reverse. The tier describes the cost split, not the quality of the doctors or the size of the network — a bronze plan and a platinum plan from the same insurer can share the same network.
The two kinds of financial help
Financial help through the exchange comes in two forms. Premium tax credits lower the monthly premium for eligible buyers, and the credit is calculated from the benchmark silver plan in your area. Cost-sharing reductions lower what you pay when you use care — deductibles, copays and coinsurance — and they are available only on silver plans, for eligible buyers. Both are worked out from your household size and income on the application, which is why the application asks for those figures before it shows you prices.
The subsidy calculator on this site estimates a premium tax credit from household size, expected income and a benchmark premium, so you can see the shape of the help before you apply.
When you can enroll
Enrollment runs on a window. On HealthCare.gov, open enrollment generally runs from 1 November to 15 January for the following year's cover, and most states follow the same window. Outside it, you generally need a qualifying life event — losing other cover, moving, marrying, having a child — to open a special enrollment period. State-run exchanges may set different deadlines, so check your own marketplace if you do not use HealthCare.gov.
Enrolling is not the same as being covered: you must also pay your first premium to activate cover, and that step catches people out every year. Treat the payment, not the application, as the finish line, and keep the confirmation the marketplace sends you.
Small business: SHOP
Small businesses have their own exchange route, the Small Business Health Options Program, known as SHOP. It lets a small employer offer its workers a choice of plans through the marketplace rather than buying a single group plan directly. It is a smaller part of the exchange system, and availability varies by state, but the idea is the same: a regulated marketplace, standardised plans, and a single place to compare them.
Worked example
Consider two ILLUSTRATIVE readers buying cover for the same year. One lives in a state that uses HealthCare.gov; the other lives in California and uses Covered California. Both enter their ZIP code and household income, both see bronze, silver, gold and platinum plans, both are offered a premium tax credit worked out the same way, and both must pay the first premium to activate cover. The websites differ, the call centres differ, and the deadlines may differ — but the plans on both are qualified health plans under the same federal rules. The example's value is the lesson that the exchange you use is decided by your state, not by preference, and that the choice that matters is the plan, not the portal.
Illustrative example only — not a fact about any real policy.