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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Claims 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.
Issue Brief Read MoreMedicaid Expansion Enrollment and Spending Leading up to the COVID-19 Pandemic
This issue brief analyzes enrollment and spending trends related to the Affordable Care Act’s Medicaid expansion ahead of the coronavirus pandemic and examines potential consequences of recent enrollment increases.
Issue Brief Read MoreJoe Biden’s New Health Care Agenda (and CMS’s Big Role In It)
With the Georgia runoff elections giving Democrats control of the U.S. Senate, Drew Altman discusses President-elect Biden’s potential health care agenda and suggests that the Centers for Medicare & Medicaid Services could have an expanded role and that it may be time to rename it and elevate it to a cabinet agency.
Perspective Read More5 Targeted Actions a Biden Administration Could Use to Expand Medicaid Coverage
The recent election of former Vice President Joe Biden as well as the on-going effects of the coronavirus pandemic and related economic downturn are the key issues that will substantially shape Medicaid policy over the next year.
Issue Brief Read MorePoll: Large Majorities Now Say They Wear Masks Regularly and Can Continue Social Distancing for At Least Six Months if Needed, though Republicans Remain Less Likely to Take Such Precautions
As winter sets in and COVID-19 cases and deaths reach records in most parts of the country, more Americans say they wear masks every time they leave home now (73%) than said so in May (52%), a new KFF Health Tracking Poll finds. A small minority (11%) say they wear…
News Release Read MoreKFF Health Tracking Poll – December 2020: COVID-19 and Biden’s Health Care Agenda
This poll examines the public’s views on the coronavirus pandemic, its mental health impacts, experiences with social distancing, face mask wearing and views on business restrictions. This poll also examines the public’s views on the Affordable Care Act and President-elect Joe Biden’s health care policy proposals.
Report Read MoreHealth Insurer Financial Performance Through September 2020
In this brief, we analyze third quarter data from 2018 to 2020 to examine how insurance markets performed financially through the end of September. Average margins remained relatively high compared to the same point in recent years, suggesting many insurers remained profitable even as non-COVID-related care returned in the summer and fall.
Issue Brief Read MoreHow Has the Pandemic Affected Health Coverage in the U.S.?
Findings from administrative data suggest that the decline in enrollment among employer-sponsored insurance was far less than overall declines in employment as of September, and that many who did lose their job-based coverage likely found a safety net in coverage through Medicaid or the ACA marketplaces.
Blog Read MorePotential Health Policy Administrative Actions Under President Biden
This brief outlines the potential health policy actions that President Biden could take using executive authority, based on campaign pledges, and actions that would reverse or modify regulations or guidance issued by the Trump Administration.
Issue Brief Read MoreMillions of Uninsured Americans are Eligible for Free ACA Health Insurance
Amid the ongoing pandemic and high unemployment, this poste xamines how many uninsured people would be eligible for free health insurance during in a typical year, including those who qualify for Medicaid or for tax credits that cover the full cost of an ACA Marketplace plan.
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