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The Second Tier of US Auto Insurers, and Why Concentration Is the Story

Short answer: The big four write 58.95% of US private passenger auto premium. Ranks 9 to 20 write 13.11%, about $48.6bn split twelve ways, and several are regional rather than national: Mercury wrote 82.1% of its premium in California, and CSAA lost $914.0m on underwriting.

By Anthony Braswell for Quorum Industries LLC, The Autobody Directory · Updated 2026-09-01 · How this was written, and what the machine may not do

How this page was produced: Researched, drafted and checked with AI assistance under human direction, and signed off by the named author. How this site is written

Below the big four, American auto insurance stops being one national market and becomes a dozen regional ones. That is the fact a shop feels first.

The four largest groups write 58.95% of US private passenger auto premium. The next twelve, ranked 9 through 20, write 13.11%: about $48.6bn between them, split twelve ways. They are not small versions of the big four. Several are single-state or single-region companies with national-sounding names, and a bad year at one of them is not spread across fifty states. It lands in one place, and every shop there feels it at once.

The ranking, and the date stamped on it

The spine is one document, the National Association of Insurance Commissioners report headed PROPERTY AND CASUALTY INSURANCE INDUSTRY 2025 TOP 25 GROUPS AND COMPANIES BY COUNTRYWIDE PREMIUM, which states it is "Based on filings received by 03/18/2026, an estimated 98.25% of Property/Casualty filings have been received." Total private passenger auto direct premiums written, all carriers, 2025: $371,041,999,429.

Two warnings travel with it. The data is preliminary by the NAIC's own account, 1.75% of filings still outstanding at the March 2026 cut, and ranks 18 to 20 sit close enough that a late filer could reorder them. And the URL is not year-stamped: the NAIC overwrites the same file each year, and that address served 2024 data before March 2026, which is why the header text and filings date are quoted above rather than merely linked.

#Group (NAIC name)Direct premiums writtenShare
9AUTO CLUB ENTERPRISES INS GRP$7,054,941,9881.90%
10AMERICAN FAMILY INS GRP$5,692,831,9191.53%
11ERIE INS GRP$5,267,967,6831.42%
12AUTO OWNERS GRP$5,163,166,6851.39%
13CSAA INS GRP$5,073,619,5201.37%
14NATIONWIDE CORP GRP$4,067,337,6611.10%
15MERCURY GEN GRP$3,563,274,9120.96%
16SENTRY INS GRP$3,070,947,5380.83%
17KEMPER CORP GRP$2,976,095,5570.80%
18AUTOMOBILE CLUB MI GRP$2,645,496,5810.71%
19HARTFORD FIRE & CAS GRP$2,318,918,8750.62%
20NEW JERSEY MANUFACTURERS GRP$1,744,813,0080.47%

"AAA" is three separate top-20 insurance groups

Three of those twelve entries are AAA carriers, and they are not one company. Auto Club Enterprises at #9, CSAA at #13 and Automobile Club of Michigan at #18 are separately capitalised, separately regulated and separately controlled, sharing a brand. Summed, they come to $14,774,058,089, or 3.98% of the market, which would place a consolidated "AAA" at #6, above Farmers. No such entity exists, and a shop treating "AAA" as one counterparty is treating three companies as one.

They are not even the same kind of company, and the difference shows in how each pays its manager. The California reciprocal at the centre of the #9 group is the Interinsurance Exchange of the Automobile Club, "managed and controlled by a seven-member Board of Governors who are members of, and appointed by, the Board of Directors of the Automobile Club of Southern California." Its attorney-in-fact, ACSC Management Services, is a wholly-owned subsidiary of that motor club, and it takes 1% of earned premium less tax plus operating expenses: $676,002,523 in 2020 rising to $841,824,717 in 2023, under an agreement "dated as of December 19, 1996" that "has never been amended." Unamended for twenty-nine years, between an insurer and the motor club that appoints its board, is a documented fact about governance. The Exchange is concentrated to match: at 31 December 2023 it was licensed in eleven states, and "$4.3 billion (93.9%)" of its direct premiums written was written in California, against surplus of $9,213,498,006.

CSAA Insurance Exchange is also a reciprocal, but "has no shareholders and is not directly owned by any party," is the ultimate parent of its own holding company system, and pays its attorney-in-fact cost-plus, "direct and allocable expenses plus a reasonable direct charge for direct overhead," $435.1m in 2020 rising to $549.4m in 2023. The Auto Club Group is a third thing again: a Michigan-based regional AAA club that "is proud to serve Members in Colorado, Florida, Georgia, Illinois, Indiana, Iowa, Michigan, Minnesota, Puerto Rico, Nebraska, North Carolina, North Dakota, South Carolina, Tennessee and Wisconsin." Its own page names no underwriting company, so which insurers make up the NAIC group "AUTOMOBILE CLUB MI GRP" at #18, and how they sit under the club, is not established here.

One of these organisations publishes its repair-program terms plainly, and it puts both halves of the steering question on one page. The Auto Club Group's page says: "You are free to select a shop that does not have an agreement with AAA." It also says the customer "may be responsible for any amounts not agreed to, or covered by AAA. This may include, but is not limited to, replacement part costs, labor, paint and material costs, storage and towing charges."

That second sentence names the estimate lines that get argued over: replacement parts, labour, paint and materials, storage and towing. A shop arguing that free choice is nominal because its cost lands on the customer need not characterise the carrier's position; it can quote it. This is The Auto Club Group's program, not CSAA's and not the Automobile Club of Southern California's, and nothing in it can be read across to either.

Concentration, in numbers

Mercury is not a national carrier with a California book. It is a California carrier. Its 2025 annual report puts 2025 direct premiums written at $4,909.8m in California, 82.1% of a $5,982.5m all-lines total, against $401.5m in Texas and $671.3m everywhere else. Mercury operates in 11 states and calls itself California's "eighth largest private passenger automobile insurer."

At 82.1%, Proposition 103 is not a compliance overhead for Mercury, it is the operating environment, and anything the California Department of Insurance does lands on four fifths of the company. Control is concentrated too: the CDI's examination of Mercury Casualty Company, filed 30 May 2023, records that George Joseph "is the ultimate controlling person," and that he and Gloria Joseph "own 35.3% and 16.5%, respectively, of MGC's stock."

CSAA is more concentrated still, and it had a very bad year. The CDI examination filed 12 February 2025 records that in 2023 the Exchange was licensed in California and Nevada only, and 100% of its direct premium, $3.77bn, was written in Northern California. Against surplus of $3,354,685,271 it posted a net underwriting loss of $(914,031,693), or $914.0m, and a net loss of $(730,427,496).

That $914.0m is the most operationally significant number here: 27.2% of surplus, absorbed in one year, on a book written almost entirely in one half of one state. We are not saying that a bad underwriting year is an allegation about CSAA's claims conduct, and it should not be read as one. It is the financial pressure a regulator recorded, and the context any 2024 to 2026 posture on severity sits in. Severity, in auto physical damage, is labour hours, parts and supplements.

NJM is the smallest carrier in the top 20, and it writes in five states. Its own site shows Connecticut, Maryland, New Jersey, Ohio and Pennsylvania, underwritten by "NJM Insurance Company and its subsidiaries," of 301 Sullivan Way, W. Trenton, and trading since 1913. How the book splits across those five states is not in any source we reached, so the share governed by New Jersey's verbal-threshold tort system and its appraisal regime is not established here.

Erie, and the case posture that is usually got wrong

The third reciprocal takes its fee a third way, and it is the one in court. Erie Insurance Exchange is the insurer. Erie Indemnity Company (NASDAQ: ERIE) is its attorney-in-fact, a separate publicly traded company, and it may "retain a management fee calculated as a percentage, not to exceed 25%, of the direct and affiliated assumed premiums written by the Exchange." The Board set that rate at 25% for 2024 and 2025 and "set the 2026 management fee rate again at 25%," on premiums that rose 8.9% to $13.0 billion in 2025.

The voting arrangement is unusual. On 17 February 2026 there were 46,189,068 Class A shares outstanding against 2,542 Class B. The Class A is the "non-voting common stock" that "trades on The NASDAQ Stock Market"; the Class B is the voting stock, and "there is no active market" for it because it "is closely held by few shareholders." The 10-K's cover page puts the Class A in non-affiliate hands at "$8.7 billion" as of 30 June 2025. A public float that size has no vote. Erie Indemnity is also the "service provider for all claims handling" for the Exchange's insurance subsidiaries, so the entity that adjusts the claim is the one whose fee is a percentage of premium, and not the one whose capital pays the loss.

Subscribers sued in state court alleging breaches of fiduciary duty in the setting of that fee, and Erie Indemnity obtained a federal preliminary injunction blocking the case on preclusion grounds. On 14 October 2025 the Third Circuit, in No. 24-1443, applied the rule that claim preclusion "does not bar claims that are predicated on events that postdate the filing of the initial complaint," found that "the District Court abused its discretion in granting Indemnity's motion for a preliminary injunction," and disposed of the appeal in a single line: "We will therefore vacate the order of the District Court granting such relief." The opinion vacates. It does not use the word remand, and nobody citing it should. The respondents' brief in opposition identifies the challenged decisions exactly, alleging that "[o]n December 10, 2019, and December 8, 2020," Indemnity "set the Management Fee rate for 2020 and 2021, respectively," at the maximum of 25%.

Rehearing was denied on 12 November 2025. Erie Indemnity petitioned for certiorari, No. 25-834, filed 12 January 2026, and the Supreme Court docket records the outcome: on 23 March 2026, "Petition DENIED."

Two things follow. Erie Indemnity's own FY2025 Form 10-K still says of that petition, "The Petition is currently pending." It predates the denial, so anyone citing the 10-K for the current posture states it wrongly; the docket is authoritative. And the win was procedural: the subscribers get to litigate, nothing more. We are not claiming that the vacatur decided anything about the management fee itself. No court has found that Erie Indemnity breached any fiduciary duty. That remains an allegation, written here as one.

The General moved, and it changed two carriers at once

American Family sits at #10 on a book that is no longer what most people think it is. On 12 September 2024 it announced an agreement to sell The General to Sentry for "approximately $1.1 billion in cash consideration," a total transaction value of $1.7 billion, on the stated basis that the business "no longer aligns with American Family's strategic focus." Chief executive Bill Westrate: "We've found a strategic and cultural fit in Sentry, where the growth and momentum that The General has will continue." American Family confirmed completion in a release dated 1 January 2025, citing Sentry's "experience in the non-standard auto segment and common mutual holding company structure."

Sentry's side is confirmed by its own regulator. The Wisconsin OCI summary dated 7 March 2025 records: "Effective December 31, 2024, SIC acquired all issued and outstanding shares of the following insurance writing companies: Permanent General Assurance Corporation, Permanent General Assurance Corporation of Ohio, and The General Automobile Insurance Company, Inc. (collectively The General) from the American Family Insurance Group (AMFAM)."

Both consequences matter. American Family's #10 position is a 2025 figure that no longer contains The General, so anything written about "American Family including The General" describes the company before 1 January 2025. And Sentry is at #16 because of that transaction alone. The same Wisconsin filing records that The General "primarily writes private passenger non-standard automobile coverage," and lists Dairyland and Viking Insurance Company of Wisconsin among Sentry's other companies. The name on the correspondence changed at the end of 2024. The book did not.

Kemper stopped being a standard carrier on purpose

On 7 August 2023 Kemper announced that it was exiting the preferred home and auto business: approximately $500 million of written premium across eight underwriting companies, with "all policies being non-renewed or canceled in accordance with applicable state regulations," and an after-tax goodwill impairment charge of $45.5 million. Kemper Auto and Kemper Life were unaffected. The rationale: "It enables us to release capital and increase the resources available to support our core specialty auto and life businesses." Kemper's own word for what it kept is "specialty": the release says the exit has "no impact on the company's specialty auto business, Kemper Auto." Its remaining $2.98bn of private passenger auto is that business. A shop thinking of Kemper as a mid-size standard carrier is working from a pre-2023 picture.

Why non-standard lands hardest on shops

A shop's exposure to this segment is out of proportion to its premium share. Non-standard policies are disproportionately liability-only, so the shop is usually handling a third-party claim: no collision coverage to fall back on, no policyholder relationship to leverage, and a liability limit that may sit below the repair cost.

The Treasury's Federal Insurance Office defines the segment, at page 5 of a January 2017 study, as covering "high risk drivers such as new drivers, drivers with moving violations, drivers with rare or unusual cars, or drivers with more frequent incidences of insurance policy cancellation or non-renewal," then declines to break it out from the wider voluntary market.

This is not a fringe occupied by unknown companies. Two top-20 groups own a non-standard writer on the documents read here: The General is Sentry's, and its regulator says it "primarily writes private passenger non-standard automobile coverage"; and National General is "an Allstate company". A third, Kemper, gave up its preferred book in 2023 and kept what it calls its specialty auto business. We do not claim that "specialty" and "non-standard" name the same thing at Kemper; the release does not settle it, and neither do we.

The best-sourced illustration of what goes wrong, among the documents read for this page, is a Texas consent order. On 17 April 2025 the Texas Department of Insurance entered Commissioner's Order No. 2025-9264 against First Chicago Insurance Company. First Chicago is not one of the twenty groups ranked above, no connection between it and any carrier named in this article was established, and this page makes no claim that its conduct is representative of any of them. It is here for what a regulator wrote down, not as a stand-in for anyone else. The conduct found includes a managing general agency agreement missing provisions the Texas Administrative Code requires, the required 2022 audit of that agency never performed, unappointed agents on 35 of 100 sampled policies, a rating error, unearned premium unrefunded or refunded late, and claims handling deficiencies: investigations running past 120 days, settlement offers delayed after liability was clear, and acknowledgement and notification deadlines missed. Citing the prompt-payment-of-claims provisions at Texas Insurance Code sections 542.055, 542.056 and 542.057, it directs that "First Chicago Insurance Company pay an administrative penalty of $150,000 within 30 days." It is an agreed order in which "First Chicago waives all of these rights," and no admission is recorded in it.

That is what the delay looks like once a regulator writes it down. The car sits, the storage accrues, and the file has a number on it.

The Hartford, and a document that may or may not still be live

The Hartford is a small personal auto writer relative to its size, at #19 and 0.62%, and that book is substantially the AARP-branded program: its own page says "The Hartford offers the only national auto insurance program endorsed by AARP" and "AARP and its affiliates are not insurers. Paid endorsement."

There is one genuinely interesting document. The Nevada Division of Insurance carries a Hartford personal auto endorsement, Form A-5660-1, edition 8/99, which puts repair-program terms into the contract rather than into marketing. The insurer will "Reduce the applicable deductible by the lesser of $100 or the Deductible amount that is shown in the Declarations" for using a participating facility, and will "Guarantee for as long as you own the repaired auto that the workmanship of the repairs met the auto repair standards of the Inter-Industry Conference on Auto Collision Repair (ICAR)." Many state anti-steering statutes reach inducements to use a particular facility, not merely instructions, and this is one printed in a regulator-filed endorsement with a dollar figure attached.

Its currency was not established, and that is the honest part. The edition is 8/99, and we did not establish that it remains in force anywhere, or that the $100 figure is current. The only current first-party source we reached describes a different bargain: the AARP page offers "access to our 1,600 authorized repair shops" and guarantees "the workmanship on all repairs," with no deductible incentive attached, and its "Disappearing Deductible" is a safe-driving benefit unrelated to shop choice. A marketing page is not a filed form and does not repeal one. We are not saying that The Hartford pays $100 today on the strength of a 1999 endorsement, and nobody else should write it on that basis either.

Mercury's penalty, stated at its actual weight

The California Insurance Commissioner fined Mercury $27.5 million for charging consumers $50 to $150 in fees on top of Department-approved premiums across more than 180,000 transactions between 1999 and 2004, collecting "at least $27,593,562 from consumers." The mechanism was labelling agents as brokers so the charges fell outside approved premium. The CDI records that the California Court of Appeal upheld the penalty on 7 May 2019, holding that "fees charged by agents acting within the scope of their agency, including Mercury's 'brokers,' are premium." Adjudicated, affirmed on appeal, not reversed and not vacated.

A separate matter is not. The Mercury Casualty examination report records as a subsequent event that "On August 1, 2022, the CDI publicly announced its intention to pursue an administrative action against the Company with respect to certain outstanding issues," arising from a 2014 Rating and Underwriting Examination Report, and that the company "cannot reasonably predict the likelihood, timing or outcome." That is an announced intention to pursue an action; its status is unknown, and it is written here as an allegation.

What we could not establish, and the walls we hit

Scrutiny across these twelve carriers was uneven, and an article implying otherwise would mislead. Where a regulator did look and cleared the claims file, we say so: North Carolina examined Nationwide Insurance Company of America for 1 January 2007 to 31 December 2009 and found that "All payments issued by the Company were deemed to be accurate. Deductibles were correctly applied and depreciation taken was reasonable," and that on total losses "All settlements were deemed equitable." That is the claims half, and only the claims half. The same examination found rating errors in 50.0% of the policies it reviewed, background checks not performed on 18.0% of producers, and non-renewal notices not sent in 100.0% of the files sampled. It imposed no monetary penalty. It is one state, it ends in 2009, and it establishes nothing about practice today.

No direct repair program was established for American Family, Auto-Owners or Erie. American Family's claims pages were not reached, and Erie's returned an empty JavaScript shell. Auto-Owners' own page describes a mutual writing in 26 states through more than 6,300 independent agencies, but names no repair program either way. We are not claiming that Auto-Owners runs little or no direct repair program: that widely repeated claim is a negative one, it needs an instrument that would have shown a program if one existed, and we have none.

No significant litigation or regulatory action was established for Kemper, The Hartford, CSAA, Auto Club Enterprises, Sentry or NJM. These are gaps, not clean bills of health: the absence of a finding is a limit of our search, not a fact about the carriers. NJM's corporate form is also unverified: it is commonly described as policyholder-owned, its own site does not say so, and we do not assert a form we did not read.

State-level premium detail does not exist in our spine. The NAIC countrywide table does not break out states, so every claim above about where a carrier is strong rests on that carrier's or that regulator's own document. American Family's, Nationwide's, Kemper's, The Hartford's and Erie's state concentrations are unestablished: Erie's 10-K gives "24 field offices in 12 states" without naming them, so neither do we.

Several items were cut for want of a source:

One correction to the source material. Auto Club Enterprises at $7,054,941,988 is the largest carrier covered here, but not larger than Erie and Auto-Owners combined, which together write $10,431,134,368. And the Interinsurance Exchange is licensed in eleven states, not nine.

Two fetch walls sit behind this page. Our command line fetcher was refused a CONNECT tunnel with a 403 on all twenty four hosts cited below, including sec.gov and supremecourt.gov; the proxy's own status endpoint attributes that to our egress policy rather than to the sites, and a second fetch path then reached all twenty four. And the Texas order at www.tdi.texas.gov is a robots disallow for our fetcher; the identical document at tdi.texas.gov without the www prefix returned in full.

Discovery was also capped: the search budget for this work was exhausted, so some gaps above exist because looking stopped, not because the material does not exist.

Corrections

This page is new, and the entries below are corrections made to its own draft before publication, not to anything a reader has seen. A page that only shows its wins is not evidence of anything, so the adversarial pass is logged here in full.

2026-09-01, Erie and the Third Circuit's disposition. The draft said the court of appeals vacated the preliminary injunction and remanded, in the section headed as being about the case posture that is usually got wrong. The slip opinion was re-read on 2026-09-01: its entire disposition is "We will therefore vacate the order of the District Court granting such relief," and it never uses the word remand. The independent report of the same opinion agrees. The page now quotes the disposition and says in terms that it does not remand.

2026-09-01, Nationwide and the North Carolina examination. The draft said the examination found nothing wrong. Re-read on 2026-09-01, the same report records rating errors in 50.0% of the policies reviewed, background checks not performed on 18.0% of producers, and non-renewal notices not sent in 100.0% of the files sampled. The claims quotations were verbatim and stay. The overstatement ran in the carrier's favour, which is the direction an error is least likely to be caught in, so it is logged here with the rest.

2026-09-01, The Hartford and the AARP endorsement. The draft dropped the words "national" and "program" from inside a quotation of the AARP page, which broadened an exclusivity claim the page does not make. The page was re-read on 2026-09-01 and the quotation now matches it word for word: "The Hartford offers the only national auto insurance program endorsed by AARP."

2026-09-01, First Chicago and the Texas order. The draft wrote "unlicensed or unappointed agents" and "rating errors." The order finds unappointed agents on 35 of 100 sampled policies, and one rating error at 1% of 100 policies. Unlicensed was never a finding. Both are now stated at the order's own weight, which is narrower than the draft's.

2026-09-01, Auto Club Enterprises and the attorney-in-fact. The draft called ACSC Management Services the Exchange's subsidiary. The examination report says it is a wholly-owned subsidiary of the Automobile Club of Southern California, the motor club whose directors appoint the Exchange's Board of Governors. Pointing at the wrong parent removed the whole point of the arrangement.

2026-09-01, NJM and a superlative. The draft called NJM the most geographically concentrated carrier in the top 20 after Mercury. That was false on this page's own figures: CSAA writes 100% of its direct premium in Northern California and is licensed in two states, against NJM's five. The claim was cut rather than rewritten, because nothing we hold ranks concentration across all twelve.

Related

Sources

Every source above was read on 2026-09-01, and every quotation on this page was re-pulled from its primary source and string matched against it before publication. Anything that would not re-verify was cut rather than softened, and the changes that altered a claim are logged under Corrections above. Two sources named in the body could not be reached at all and were therefore cut: the 2017 Minnesota consent orders sit behind an authenticating state portal we could not enter, so no carrier is named for them, and American Family's claims pages did not return while Erie's returned an empty JavaScript shell, which is why no direct repair program is asserted for either. This page is not legal advice, and nothing in it is investment or financial advice about any insurer.

General consumer information: not legal, insurance, or financial advice. Requirements, coverage, and practices vary by state, policy, and manufacturer.

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