The U.S. Government Accountability Office (GAO) released a report in December 2025 highlighting significant vulnerabilities and instances of fraud in the Advance Premium Tax Credit (APTC) Program, which provides subsidies to reduce health insurance premiums under the Affordable Care Act (ACA, or Obamacare). Key findings on the scale of improper payments and fraud include:

– – Overall Program Scale and Unreconciled Payments: The Centers for Medicare & Medicaid Services (CMS) estimated $124 billion in APTC payments for 19.5 million enrollees in plan year 2024. A preliminary analysis identified over $21 billion in unreconciled APTC (representing 32% of APTC for enrollees who provided Social Security Numbers in plan year 2023), which could indicate overpayments or fraud but is not yet fully verified.
– – Payments to Deceased Individuals: CMS disbursed over $94 million in APTC for households where Social Security Numbers matched Social Security Administration death data in plan year 2023. Over 58,000 such SSNs (0.42% of those receiving APTC) were flagged, with CMS failing to conduct periodic reviews for all enrollees.
– – Identity Theft and SSN Misuse: More than 29,000 SSNs (0.21%) in plan year 2023 and nearly 66,000 (0.37%) in plan year 2024 had over 365 days of coverage, suggesting potential identity theft or errors. GAO’s covert testing revealed weak controls, with all four fictitious applications in 2024 and 18 of 20 in 2025 receiving subsidized coverage despite invalid SSNs, fictitious documentation, and unverified income or citizenship. This resulted in about $2,350 in monthly APTC for late-2024 tests and over $10,000 monthly for active 2025 fictitious enrollees.
– – Unauthorized Enrollment Changes: At least 30,000 applications (0.4%) in plan year 2023 and 160,000 (1.5%) in plan year 2024 showed signs of unauthorized changes by agents or brokers, such as multiple brokers editing the same application on the same day. CMS received 275,000 complaints about unauthorized enrollments or plan switches from January to August 2024, with some leading to indictments for falsified applications.

The report notes that fraud is exacerbated by incentives for brokers (paid per enrollment) to enroll ineligible individuals, potentially leading to consumer harm like loss of provider access, higher costs, or subsidy repayments. GAO recommended CMS update its outdated 2018 fraud risk assessment, strengthen controls (e.g., SSN verification and death data reviews), and develop an antifraud strategy. Estimates from external analyses, such as one by the Paragon Health Institute, suggest federal spending on ineligible enrollees could exceed $20 billion in 2024.

On December 15, 2025, House Judiciary Committee Republicans sent letters (described in some contexts as demands under subpoena authority) to the CEOs of eight major health insurance companies as part of an oversight probe into ACA subsidy fraud, triggered by the GAO report.

The House Judiciary Committee sent letters to Blue Shield of California, Centene Corporation, CVS Health, Elevance Health, Kaiser Permanente, Oscar Health Inc. and GuideWell, demanding detailed information on their enrollment services.

These companies are involved in offering ACA marketplace plans, facilitating enrollments through brokers or agents, and receiving APTC subsidies on behalf of enrollees. The probe focuses on their role in potentially enabling or overlooking fraud, such as through broker incentives that encourage improper enrollments. The committee requested documents on enrollment numbers, unused benefits, internal fraud communications, and anti-fraud staff.

Some of the fraud comes from brokers, who are paid by insurance companies for each enrollment and are, therefore, incentivized to enroll as many people as possible – whether eligible or not. Brokers have targeted individuals with deceptive advertisements and pressured enrollees to lie about their incomes to obtain Obamacare subsidies. Evidence suggests that many individuals do not even know they are signing up for health insurance or agreeing to switch plans.

Last year, a federal judge blocked a regulation issued by the Trump Administration to fight Obamacare subsidy fraud, claiming it violated the Administrative Procedure Act.