By Healthcare Brew Staff
3 min read
Definition:
The Affordable Care Act (ACA) marketplace is a website (healthcare.gov) where individuals, families, and small businesses can compare and buy health insurance from private payers.
The basics
The term typically refers to the federally run marketplace, which is also called an exchange. Some states run their own exchanges, too.
The marketplace was created as part of (you guessed it!) the Affordable Care Act, 2010’s sweeping healthcare reform law.
Marketplace plans have four main categories, in order from least to most coverage, respectively: bronze, silver, gold, and platinum. A bare-minimum coverage category, catastrophic, is also available to certain qualifying individuals based on hardship exemptions.
Regardless of tier, all marketplace plans must cover 10 essential health benefits established by the ACA, which has also been informally referred to as “Obamacare.”
What about tax credits?
Some marketplace enrollees are eligible for financial assistance, or subsidies, from the federal government in the form of premium tax credits. These help blunt the impact of year-over-year premium increases and stabilize the marketplace.
The government temporarily increased the size and scope of these subsidies in March 2021. The 2022 Inflation Reduction Act extended those enhanced subsidies until the end of 2025. During that period, marketplace enrollment spiked from 11.4 million in 2019 to 24.3 million in 2025, per research nonprofit KFF.
The subsidies expired Jan. 1, 2026, after a debate in Congress that culminated in a government shutdown. After the expiration, eligibility reverted back to people with incomes from 100% to 400% of the federal poverty level. Enrollment fell as a result, and people switched to plans with less coverage.
Consumers can also buy individual health coverage “off exchange” via alternative offerings. Plans bought outside the marketplace are not eligible for premium tax credits, however.
How to sign up
Enrollment primarily takes place during the open enrollment period, which is Nov. 1 to Dec. 15, as of fall 2026, one month shorter than the last few years. Qualifying life events like marriage can trigger a special enrollment period outside that window.
During the open enrollment period for 2026 plans (which took place primarily in 2025), 23.1 million people enrolled or were automatically re-enrolled in marketplace coverage, per federal data.
The top individual market insurers in 2024 by market share were Centene, HCSC, and CVS, per KFF. CVS’s Aetna left the marketplace starting in the 2026 plan year. Cigna announced in May 2026 it would leave for the 2027 plan year.
