Independent Reviewers Overturned 72 Percent of California Insurance Denials in 2025; Fewer Than 1 Percent of Denials Are Appealed, Apellica Benchmark Finds
New reproducible tabulations of CMS insurer filings, 42,710 California independent medical reviews and state external-review reports: a nine-fold spread in denial rates between insurers under the same rules, 3.2 appeals per 1,000 denials, and the treatments reviewers reverse most and least.
NEW YORK, September 15, 2026 — Apellica today published the Denial and Appeal Benchmark 2026, a set of reproducible tabulations of the three public records that document how often U.S. health insurers deny claims and how often those denials survive an appeal: the filings HealthCare.gov insurers make to CMS, every Independent Medical Review decision published by California's Department of Managed Health Care, and the external-review reports of state regulators.
Findings
- Independent reviewers sided with patients 72 percent of the time in California in 2025, up from 51 percent in 2015. Across all 42,710 decisions since 2001, 52.5 percent went the patient's way. New York's external-appeal record, analyzed in JAMA Internal Medicine this year, shows the same direction: 38 percent in 2019 to 52.5 percent in 2025.
- Members appealed 3.2 of every 1,000 in-network denials in 2024. Among HealthCare.gov issuers with at least 100,000 denials, the appeal rate runs as low as 0.2 per 1,000. Among issuers with at least 100 appeals, the share overturned runs from 0 percent to 86 percent.
- A nine-fold spread under the same rules. Among the 178 issuer filings with at least 1,000 in-network claims, the reported denial rate runs from 4.0 percent to 35.6 percent.
- By state, the typical insurer's denial rate ranges from 4.1 percent (South Dakota) to 28.0 percent (Delaware). Oklahoma, Alaska, West Virginia and Texas follow Delaware.
- Single issuers moved more than 20 points in one year: AmeriHealth Caritas Florida from 53.9 to 25.7 percent, Blue Cross and Blue Shield of Montana from 39.5 to 12.5 percent, UnitedHealthcare Insurance Company in Alabama from 41.6 to 17.9 percent. Oscar filings rose 7 to 11 points in five states.
- The treatments independent reviewers reverse most: viscosupplementation injections (93.8 percent), mammography (93.2 percent), weight-control drugs (86.3 percent). The least: artificial disc replacement (9.8 percent), inpatient admission (25.6 percent), spinal fusion (28.0 percent).
- Children under 11 win two-thirds of independent reviews; patients over 65 win under half.
Method
Every figure is computed from datasets published on apellica.com and downloadable as CSV under a Creative Commons Attribution license, with methodology and source notes. CMS figures are self-reported by issuers at the issuer-and-state level, cover HealthCare.gov plans in 32 states, and count every denial reason including duplicate and administrative denials; the file for a plan year carries claims from two years earlier. The California record is the population of cases that reached independent review, not a sample of all denials. Nothing in the benchmark predicts an individual claim.
Reports and data: https://apellica.com/research · Open data release: https://github.com/skipthetask1-maker/apellica-insurance-denial-data
About Apellica
Apellica, Inc. prepares and files health-insurance appeals for patients at no upfront cost and publishes the public record of denials and appeals. It is not a law firm and is not affiliated with any insurer or government agency.
Media: press@apellica.com · Data corrections: editorial@apellica.com