ACA claim denial rates fell in 2024 — but remain historically high

ACA marketplace insurers denied 19.1% of in-network claims in 2024 — 8.8 million rejected claims out of 46 million submitted. The rate fell from 22.5% in 2023, the largest single-year drop on record, but remains above the 2021 baseline of 16.7%. Fewer than 1% of those 8.8 million denials were appealed. Of the claims that were appealed, insurers upheld their own denials 56% of the time. A separate study found 57% of denied Medicare Advantage claims are overturned when appealed — evidence that most denials are reversible, and that the gap between what's contested and what's recoverable is enormous.