Top 10 US Insurers by NAIC-Recorded Complaint Index Composite
NAIC complaint-index, denial-rate, and prior-authorization composite score across 209 US insurance companies, updated automatically as new NAIC and CMS filings are processed.
Research period:
What this ranks: PlainInsurer's composite of the NAIC complaint index, CMS claim-denial rate, and Medicare Advantage prior-authorization filing volume, not financial strength, customer service, or which insurer is right for you. Coverage needs, state availability, and price vary by person, compare quotes and see the full methodology before choosing a carrier.
Research question
Among 209 US insurance companies tracked across NAIC complaint, prior-authorization, and CMS denial-rate sources, which carry the highest composite score and how does that score distribute across the major lines of business?
Methodology
This ranking reflects the 10 insurers with the highest composite score -- PlainInsurer's 0-100 quality index built from the NAIC Consumer Information System and the CMS Transparency in Coverage rollup, where a HIGHER score means fewer complaints and denials relative to size, not more. Every figure updates automatically as new NAIC and CMS filings are processed; nothing on this page is hand-entered.
Coverage and exclusions: NAIC and CMS occasionally suppress values for confidentiality, small sample size, or quality control, and suppressed rows are excluded from this ranking rather than shown as zero. If either agency later revises a figure, the revised value replaces the old one automatically the next time the portal's data is refreshed.
Data provenance: NAIC and CMS each publish their respective datasets on their own release schedules. We pull each release as it becomes available and normalize it into our database; a later release simply supersedes the one before it, so readers never see a mix of old and new figures on the same page.
Comparability across years: when NAIC or CMS revises its release schedule, definitions, or coverage, we note the affected years on the methodology page so readers can compare like-with-like rather than across a changed measurement.
Editorial governance: PlainInsurer publishes its editorial policy and corrections process. If an insurer disputes a figure attributed to it, the correction is checked against the official NAIC or CMS record before any change is made.
Every number on this page can be traced back to its NAIC or CMS source by following the entity links and the citation below, so independent verification never requires anything beyond the original public source.
See the methodology page for the complete ETL pipeline, source vintage, and column lineage.
Top 10 US Insurers by NAIC-Recorded Complaint Index Composite
Live data: reflects the current NAIC and CMS composite snapshot
The ranked top 10
Every row below reflects the current 10-company dataset. Reload the page after new NAIC or CMS data is processed to see the latest values.
| # | Insurer | NAIC code | NAIC complaints | Complaint sub-score | Denial sub-score | Composite score |
|---|---|---|---|---|---|---|
| 1 | Imperial Insurance Companies, Inc. | 0 | — | 98.9 | 98.9 | |
| 2 | Avera Health Plans, Inc. | 0 | — | 98.3 | 98.3 | |
| 3 | PacificSource Health Plans | 0 | — | 97.7 | 97.7 | |
| 4 | Sanford Health Plan | 0 | — | 96.6 | 96.6 | |
| 5 | HealthPartners Insurance Company | 0 | — | 95.5 | 95.5 | |
| 6 | Kaiser Foundation Health Plan, Inc. | 0 | — | 94.9 | 94.9 | |
| 7 | Priority Health | 0 | — | 94.4 | 94.4 | |
| 8 | Quartz Health Benefit Plans Corporation | 0 | — | 93.2 | 93.2 | |
| 9 | Providence Health Plan | 0 | — | 93.2 | 93.2 | |
| 10 | Group Health Cooperative of South Central Wisconsin | 0 | — | 91.5 | 91.4 |
Source: NAIC and CMS, NAIC Consumer Information System + CMS Transparency in Coverage rollup. Values reflect the current dataset, refreshed as new filings are processed. NAIC and CMS, NAIC Consumer Information System + CMS Transparency in Coverage rollup. Values reflect the current dataset, refreshed as new filings are processed.
Findings
Top entity in the ranking
The top-ranked record in this dataset is Imperial Insurance Companies, Inc., with a composite score of 98.9. The full top-10 set is rendered in the table above. When the source agency publishes a revision, the ranking and the prose around it update automatically.
Distribution shape
The gap between the top-ranked record (98.9) and the 10th-ranked record (91.4) characterizes how concentrated the top of the distribution is. Where the top value is many multiples of the median value of the visible set, the population is highly concentrated, a small number of entities accumulate the bulk of the measured quantity. Where the top and bottom of the visible set are close together, the distribution is relatively flat across the top end. The full distribution beyond this top-10 cut is summarized in the aggregate context section below and explored in the linked entity profiles.
Aggregate context
The figures below situate the top-10 ranking against the full population: how many companies exist in total, and what the average composite score looks like across all of them.
Source provenance
The records in this ranking originate from NAIC and CMS, specifically the NAIC Consumer Information System + CMS Transparency in Coverage rollup. Plaininsurer ingests the source vintage published by the agency and keeps this page current, there is no static export carrying stale numbers, and a newly published dataset is reflected here within hours. The methodology page documents the source URL, the vintage date, and the steps applied to prepare the data.
Why this ranking matters
Rankings like this one let a reader scan a population quickly and identify outliers, concentrations, and patterns that warrant deeper investigation. The detail pages linked from each entity in the table above give the full per-entity context: time-series history where available, related metrics from adjacent tables, and links onward to the underlying source records. The methodology page explains how an entity earns inclusion in the dataset and how the ranking column is computed at the source.
What this analysis cannot tell us
The composite score is computed by aggregating three sub-components (NAIC complaint index, CMS Transparency in Coverage denial rate, and prior-authorization filing volume) using documented weights, see the /methodology page. The weights and component definitions are PlainInsurer editorial choices applied uniformly across all 209 companies; a different weighting would produce a different ranking. NAIC complaint index uses the standard NAIC methodology of complaints divided by market share, large companies with many complaints can have a complaint index close to the national median of 1.0, while small companies can be volatile across years. Denial-rate data from CMS Transparency in Coverage covers ACA-marketplace plans and reflects claims activity for in-network providers under specific plan years; commercial group plans and Medicare Advantage report under different regimes. Prior-authorization sub-scores are based on filing volume and reflect administrative complexity, not necessarily the clinical justification of denials. Reputation grades A through F are an editorial assignment using composite-score cutoffs documented in the methodology. This page reports figures as recorded; it is not advice on which insurer to choose for a policy purchase or any other coverage decision.
Secondary cut from the same source
Top 10 insurers by CMS Transparency-in-Coverage denial sub-score component
Sources
- National Association of Insurance Commissioners (NAIC) - Consumer Insurance Search - https://content.naic.org/cis_consumer_information.htm
- Centers for Medicare & Medicaid Services, Transparency in Coverage Public Use Files - https://www.cms.gov/marketplace/resources/data
- NAIC, Annual Statement Database - https://content.naic.org/industry_isite_filings.htm