01What happened

The story, straight

In 2024, the largest plans sold on the Affordable Care Act marketplace denied between 13% and 35% of in-network claims their members filed, according to federal HealthCare.gov data. Nationally, marketplace insurers denied roughly 1 in 5 in-network claims. The data, compiled by data scientist Randal Olson, highlights wide variation depending on which insurer issued the policy. The analysis arrives as claim denials are back in the national spotlight: Luigi Mangione, charged in the December 2024 killing of UnitedHealthcare CEO Brian Thompson, was back in court this week for a pretrial hearing, and legal analysts expect his trial to become a referendum on a health care system many Americans find costly and opaque.

The analysis lands while the Mangione case — involving Luigi Mangione, charged in the December 2024 killing of UnitedHealthcare CEO Brian Thompson — is back in court this week, and his trial is shaping up to be a proxy fight over how the entire system operates.

02Spread timeline

Where it actually started

Jun 16, 2026Origin
Data scientist Randal Olson publishes analysis of ACA marketplace claim denial rates using federal HealthCare.gov data.Randal Olson drops an ACA denial-rate analysis using federal data
source
Jun 21, 2026
The post surfaces on Hacker News, drawing community attention to the insurer disparity.the analysis hits Hacker News front page
source

03Source receipts

Every claim, linked

04What's solid, what isn't

What's solid and what isn't

Confirmed
  • ACA marketplace insurers denied between 13% and 35% of in-network claims in 2024.
  • Nationally, marketplace insurers denied roughly 1 in 5 in-network claims.
  • Luigi Mangione was back in court this week for a pretrial hearing related to the December 2024 killing of UnitedHealthcare CEO Brian Thompson.
Disputed
  • Whether the disparity reflects differences in plan design, patient demographics, or insurer aggressiveness in denying claims.
Developing
  • Mangione's trial is expected to focus public attention on insurer denial practices ahead of the proceedings.

05Why it matters

The editorial take

The disparity between insurers is stark: the worst-performing plan denied claims at nearly three times the rate of the best. That kind of variation means a patient's out-of-pocket risk depends almost entirely on employer or marketplace plan selection — something most consumers have little visibility into. As political scrutiny of insurer practices intensifies around the Mangione case, this federal data gives the debate hard numbers instead of anecdotes.

This all comes as the Mangione trial turns into a public reckoning.