Aon vs At Bay: Professional Liability / E&O Insurance

Aon is a brokerage and advisory service for law, accounting and consulting firms; At-Bay offers its own MPL product, with limits up to $5 million, to licensed insurance professionals who submit business.

Kearny Risk organizes these comparisons for firms whose advice, content or technology creates professional exposures.Research updated 2026-09-30

What Are the Key Differences Between Aon and At-Bay Professional Liability (E&O) Insurance?

Coverage Structure and Evidence

Aon describes professional liability as addressing firms’ liability exposure and says it tailors coverage structures, but its practice overview does not state limits or policy triggers. At-Bay lists primary miscellaneous professional liability with limits up to $5 million, subject to state restrictions and appetite. It also describes a claims-made-and-reported form, independent-contractor coverage and defense for disciplinary proceedings. Buyers can use those published features as specific questions for Aon and verify which apply to their At-Bay quote. [1] [5]

Buyer Fit and Placement

At-Bay directs licensed insurance professionals to submit business through its disclosed producer, rather than describing a direct retail route; it does not name the current issuing insurer on the product page. Aon likewise acts as a broker/adviser and leaves the placement carrier unspecified. Both require quote-level confirmation. Ask whether the $5 million ceiling is available in your state and profession, and compare the definitions, duty to defend and hammer clause. [1] [5]

What Should You Confirm in Aon and At-Bay Professional Liability (E&O) Insurance Quotes?

  • Ask At-Bay which insurer issues the current quote and whether your state and profession qualify for the stated ceiling. [1] [5]
  • Ask Aon to provide comparable MPL limits, claims-made reporting terms and defense wording. [1] [5]

Areas of coverage

Aon

  • role: Aon presents Professional Liability / E&O as a line its Professional Services Practice helps arrange or advise on for professional-service firms. Aon is describing a global brokerage and advisory service, not issuing the underlying policy. The producing legal entity and carrier for any particular placement are not named on this page. Aon’s global professional-services practice page. This establishes a marketed brokerage/advisory offering, not policy issuance or account-specific placement.company-reportedSource ↗
  • eligibility: Aon identifies law, accounting and consulting firms as the audience for its global Professional Services Practice. That audience scope does not establish eligibility for every firm or other business. Audience described for Aon’s global professional-services practice. It does not establish U.S. state availability or underwriting eligibility for a placement.company-reportedSource ↗
  • coverage: Aon describes professional liability as addressing professional-services firms’ liability exposure and says it tailors coverage structures to a firm’s needs. It identifies E&O as a commonly used name for professional-liability insurance; actual policy terms are not stated. Aon’s marketing description of the brokerage/coverage area. The page is not the insurer’s policy form and does not establish an insured's entitlement to coverage.company-reportedSource ↗
  • services: Aon says its professional-services advisors use industry knowledge, insights, data and tools to support risk-management and human-capital decisions. This is a company-described advisory service, not a claim outcome or policy benefit. Company-reported advisory services on Aon’s global practice page; account-specific service scope is not stated.company-reportedSource ↗
  • insurer: The reviewed practice page does not name the insurer or producing legal entity for a specific placement. Ask for both on the quote and binder. Aon’s global practice page as reviewed 2026-09-30; no state-specific placement schedule or buyer quote was reviewed. This does not establish that Aon cannot arrange a placement.not-foundSource ↗
  • limits: The reviewed page does not state a buyer-specific limit, retention, deductible or other placement terms. Confirm these in the quote, bond or issued policy. Aon’s global practice page as reviewed 2026-09-30; no quote, bond form or issued policy was reviewed.not-disclosedSource ↗

At-Bay

  • role: At-Bay markets MPL as one of its own named insurance products, sold through its disclosed producer, At-Bay Insurance Services LLC, with the product page directed at "properly licensed insurance professionals" submitting business rather than at direct retail buyers. Current MPL product page and license disclosures; this describes the distribution channel, not who bears the underwriting risk.company-reportedSource ↗Source ↗
  • insurer: The current MPL product page does not name the insurer that issues the policy. A September 2023 press release named United Specialty Company in connection with MPL, but that historical reference does not establish the current issuing insurer for a new MPL quote. Reviewed MPL page as of 2026-09-23 and the September 2023 press release; restates the existing provider fact that MPL's current issuer is unresolved, distinct from the August 2023 Cyber/Tech E&O transition to At-Bay Specialty Insurance Company paper.not-foundSource ↗Source ↗
  • eligibility: At-Bay says it provides primary MPL for businesses of all revenue sizes with limits up to $5 million, subject to state restrictions and eligibility requirements detailed in a separate MPL appetite guide. Current MPL appetite paragraph; the linked appetite guide's specific eligibility requirements were not independently opened for this record.company-reportedSource ↗
  • coverage: At-Bay lists MPL coverage highlights including automatic coverage for acquired subsidiaries, claims-made-and-reported coverage, coverage for independent contractors, disciplinary-proceedings defense, a duty-to-defend contract, personal-injury coverage (including emotional distress), punitive damages where insurable, a professional-services definition written for each insured, and an 80/20 hammer clause. Product-page coverage-highlights list; an 80/20 hammer clause is a settlement provision where the insurer pays 80% and the insured pays 20% of costs after the insured declines a recommended settlement. The issued policy and declarations control actual wording, limits and exclusions.company-reportedSource ↗
  • limits: At-Bay publishes an MPL limit ceiling of up to $5 million, with state restrictions that are not detailed on the product page itself. Current appetite paragraph; this is an advertised ceiling, not a guaranteed available limit for any specific applicant.company-reportedSource ↗
  • application: At-Bay directs MPL submissions to underwriting by email or through automatic quotes on its Broker Platform, which At-Bay describes as a workflow of creating a quote, customizing limits and retentions, and binding the policy. Current submission instructions and the general broker-platform workflow description; MPL-specific automation details were not separately confirmed.company-reportedSource ↗Source ↗

Aon says it tailors professional-liability structures for professional firms but publishes no terms. At-Bay describes primary MPL up to $5 million with claims-made coverage and specified features.

Sources reviewed

  1. 01
    Professional Services Practice

    Aon · Named professional-services audiences and global advisory role, lines 125–128; line offerings and explanations lines 131–190; contact link lines 120–122. Global practice page; no U.S. state or account-specific placement schedule. · accessed 2026-09-30

  2. 02
    At-Bay Doubles Miscellaneous Professional Liability Appetite

    At-Bay · September 28, 2023 release: final paragraph before Media Contacts · accessed 2026-09-16

  3. 03
    Broker Platform

    At-Bay · How it works: Create a quote, Customize your quote, Bind your policy, Manage renewals; FAQs · accessed 2026-09-16

  4. 04
    Licenses

    At-Bay · Producer introduction; agency and surplus-lines footer naming At-Bay Insurance Services LLC · accessed 2026-09-16

  5. 05
    MPL Insurance: Coverage Highlights & Appetite

    At-Bay · MPL Coverage Highlights list; MPL Appetite paragraph; Send us your submissions; "material on this page is intended for use solely by properly licensed insurance professionals" · accessed 2026-09-23

  6. 06
    Professional Liability – US Direct Errors and Omissions Insurance

    Hiscox Inc. specimen · About this Policy / Coverage for Claims Made Against You; I.A Insuring Agreement; I.B Defense; I.C Settlement; II.A Notice of Claims; II.C Optional Extended Reporting Period; III.A, III.K, III.M, III.R, III.S Exclusions; IV.A–B Limits and Deductible; VI.O Professional Services; VI.U Wrongful Act · accessed 2026-09-16

  7. 07
    Professional liability insurance

    Insurance Information Institute · Opening paragraphs (professional services/advice and E&O name); Claims not covered by general liability; What types of businesses need professional liability insurance?; What’s covered… and what’s not (claims-made versus occurrence, defense and judgments, non-financial/intentional limits, BOP/in-home exclusion) · accessed 2026-09-16

  8. 08
    FAQ: Professional liability insurance

    Texas Department of Insurance · What’s professional liability coverage?; What types of damages…; What’s general liability insurance?; Do I need professional liability… if I have general liability…?; Is professional liability insurance required?; Can a client require…?; What’s the difference between occurrence policies and claims-made policies · accessed 2026-09-16

  9. 09
    Get business insurance

    U.S. Small Business Administration · Six common types of business insurance table · accessed 2026-09-16

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