More than a decade after its enactment, tens of millions of people nationwide rely on coverage options created through the Affordable Care Act of 2010 (ACA). The law has survived multiple court challeges at the U.S. Supreme Court and repeated attempts by Republicans in Congress to repeal it. Subsequent legislation has scaled back some aspects of the law and expanded others, including by the COVID-19 relief bill, the American Response Plan Act of 2021. This page highlights relevant analysis about the ACA and proposed and enacted changes to it..
For information about ACA Marketplace Open Enrollment, including fact sheets and 300+ FAQs, visit our collection of resources on Understanding Health Insurance.
Featured Affordable Care Act Resources

Potential Costs and Impact of Health Provisions in the Build Back Better Act
A summary of 10 of the major health coverage and financing provisions of the current Build Back Better Act, with discussion of the potential implications for people and the federal budget.
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Related Affordable Care Act Resources
- 5 Charts About Public Opinion on the Affordable Care Act
- A Closer Look at the Uninsured Marketplace Eligible Population Following the American Rescue Plan Act
- Eligibility for ACA Health Coverage Following Job Loss
- Pre-Existing Condition Prevalence for Individuals and Families
- Building on the Evidence Base: Studies on the Effects of Medicaid Expansion, February 2020 to March 2021
- FAQs: Health Insurance Marketplace and the ACA
- Explaining Health Care Reform: Questions About Health Insurance Subsidies
- Status of State Medicaid Expansion Decisions: Interactive Map
- Preventive Services Tracker
- Tracking Section 1332 State Innovation Waivers

How Marketplace Costs and Premiums will Change if Rescue Plan Subsidies Expire
In this Policy Watch we explore the potential impact of the expiration of the American Rescue Plan Act’s enhanced financial help and new eligibility for the Affordable Care Act’s health insurance Marketplace federal subsidies. While the COVID-19 relief legislation passed earlier this year provides greater subsidy assistance through 2022, Democrats in Congress are currently considering making the temporary federal help permanent or extending it as part of their planned budget reconciliation legislation.
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KFF Health Tracking Poll: Economic Hardship, Health Coverage, And The ACA
This poll examines the public’s assessments of the Biden administration’s handling of the coronavirus pandemic, the impact COVID-19 has had on people’s finances, and support for provisions of the latest COVID-19 relief bill. It examines the public’s views of the ACA and possible next steps.
Poll Finding Read MoreSurvey: OBGYNs Report That the Affordable Care Act Has Increased Use of Contraceptives Among Patients, but the Cost of Reproductive Health Care Still a Burden for Their Low-Income Patients
This report highlights key findings from the 2020 KFF National Physician Survey on Reproductive Health that asked a nationally representative sample of OBGYNs practicing in the United States about a wide range of issues, including their provision of contraception, abortion, and STI care.
News Release Read MoreOBGYNs and the Provision of Sexual and Reproductive Health Care: Key Findings from a National Survey
This report highlights key findings from the 2020 KFF National Physician Survey on Reproductive Health that asked a nationally representative sample of OBGYNs practicing in the United States about a wide range of issues, including their provision of contraception, abortion, and STI care.
Report Read MoreTwo New Analyses: House COVID-19 Relief Plan Would Temporarily Lower Marketplace Premiums for Millions and More than Offset Short-Term State Costs to Expand Their Medicaid Programs
The House COVID-19 relief proposal would temporarily lower what millions of Marketplace enrollees and uninsured potential enrollees would pay toward premiums and would provide states that have not expanded their Medicaid programs a financial boost that would more than offset their costs initially, two new KFF analyses find. The analyses…
News Release Read MoreWhat to Expect During the COVID Marketplace Enrollment Period
This post provides details about the ongoing Special Enrollment Period to sign up for health coverage on the ACA exchanges, including who is eligible to enroll, how costly Marketplace insurance is on average, and what other factors will affect enrollment during this period.
Blog Read MoreACA Open Enrollment Matters for Medicaid Coverage, Too
President Biden’s January 28th executive order to reopen enrollment in the federal ACA Marketplace from February 15 through May 15, combined with $50 million in federal spending on outreach and education about ACA coverage options, has the potential to reach millions of people who were uninsured prior to or have lost coverage during the pandemic. As of 2019, there were 29 million non-elderly uninsured people, and the majority (57%) were eligible for financial assistance through the ACA Marketplaces (33%) or Medicaid (25%). KFF estimates indicate that nearly nine million uninsured people could be eligible for free or subsidized Marketplace coverage during the new enrollment period. Importantly, these actions to facilitate enrollment in ACA Marketplace coverage will also likely lead eligible low-income people to enroll in Medicaid coverage.
Blog Read MoreNearly 9 Million Uninsured Americans Could Get Free or Subsidized Health Insurance if the Biden Administration Re-Opens ACA Marketplace Enrollment in Response to COVID-19
Four million uninsured people could get an ACA bronze plan with no premium payment and 4.9 million others could get subsidies to offset the cost of such a plan if the Biden Administration were to re-open ACA marketplace enrollment, a KFF analysis finds. Four million uninsured people could get an…
News Release Read MoreOpportunities and Resources to Expand Enrollment During the Pandemic and Beyond
This analysis summarizes recent interviews with marketplace navigators and other consumer assistance professionals, who offered observations about the 2021 Open Enrollment period, discussed general and pandemic-specific challenges facing consumers seeking coverage, and offered suggestions to improve enrollment outcomes. The brief also reviews information about federal marketplace resources and spending priorities contained in Trump Administration budget documents, and possible sources of funding for a COVID-19 special enrollment period during the Biden administration.
Issue Brief Read MoreThe Coverage Gap: Uninsured Poor Adults in States that Do Not Expand Medicaid
In states that do not implement the Medicaid expansion under the Affordable Care Act (ACA), many adults will fall into a “coverage gap” of earning too much to qualify for Medicaid but not enough to qualify for Marketplace premium tax credits. Nationwide, 2.2 million poor uninsured adults are in this situation. This brief presents estimates of the number of people in non-expansion states who could have been reached by Medicaid but instead fall into the coverage gap and discusses the implications of them being left out of ACA coverage expansions.
Issue Brief Read MoreClaims Denials and Appeals in ACA Marketplace Plans
Based on an analysis of transparency data released by the Centers for Medicare and Medicaid Services (CMS), this brief assess claims denials and appeals among issuers offering individual market coverage on healthcare.gov and finds that 17% of in-network claims were denied by issuers in 2019, with denial rates for specific issuers varying significantly around this average, from less than 1% to more than 50%. Consumers appealed less than 1% of denied claims.
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