What Is Aon?
Aon’s U.S. Commercial Risk terms describe brokerage for certain insurance programs, while its Middle Market page describes a dedicated practice for mid-sized organizations across North America. The public materials reviewed do not identify the licensed producer or insurer for a particular placement. Ask which entity will produce each line and which insurer will issue the policy; request jurisdiction details for the proposed placement and ask how compensation and claim notice work for your account. 1,2
What Is At-Bay Insurance?
At-Bay targets technology firms with up to $5 billion in revenue and offers cyber limits up to $10 million, plus technology E&O; buyers seeking a standard online business package should compare other carriers. Managed detection and response costs extra. 4,5
What Is Professional Errors and Omissions (E&O) Insurance?
Professional liability can help pay defense costs and covered losses when a client says your advice or service caused financial harm. If customers rely on your work, list every service you provide and check the claims-made reporting and prior-work terms. 10,11,12,13
Key Differences in 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. 3 6
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. 3 6
What to Confirm in Professional Liability (E&O) Insurance Quotes
Review Scores
These averages can combine ratings for different products, locations, and customer groups, including approximate BBB grade conversions. Read each review for the sources, scope, and calculation.
Aon
Review Score
3 rated sources
Public ratings for Aon are low: Trustpilot shows 1.2 out of 5 from 782 reviews, and BBB shows 1.6 from five. Aon is a global firm, so those pages mostly reflect other parts of the business, not large U.S. commercial accounts.[4][6][7]
Read Aon reviewsAt-Bay
Review Score
2 rated sources
At-Bay’s public review evidence is thin: one old G2 review and a BBB complaint record. It is not enough to judge day-to-day service or claims handling.[3][6][9]
Read At-Bay reviewsOffering Details
Aon vs At-Bay: Professional Liability (E&O) Insurance: documented features by provider
| Criteria | Aon Professional Liability / E&O brokerage and risk-advisory offering | At-Bay Miscellaneous Professional Liability (MPL) Insurance |
|---|---|---|
| Role in This Line | 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. 3Company-reported. Aon’s global professional-services practice page. This establishes a marketed brokerage/advisory offering, not policy issuance or account-specific placement. | 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. 6,7Company-reported. Current MPL product page and license disclosures; this describes the distribution channel, not who bears the underwriting risk. |
| Issuing 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. 3Not found in reviewed sources. 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. | 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. 6,8Not found in reviewed sources. 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. |
| Who It’s For | 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. 3Company-reported. Audience described for Aon’s global professional-services practice. It does not establish U.S. state availability or underwriting eligibility for a placement. | 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. 6Company-reported. Current MPL appetite paragraph; the linked appetite guide's specific eligibility requirements were not independently opened for this record. |
| Coverage Features | 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. 3Company-reported. 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. | 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. 6Company-reported. 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. |
| Limits and Retentions | 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. 3Not publicly disclosed. Aon’s global practice page as reviewed 2026-09-30; no quote, bond form or issued policy was reviewed. | At-Bay publishes an MPL limit ceiling of up to $5 million, with state restrictions that are not detailed on the product page itself. 6Company-reported. Current appetite paragraph; this is an advertised ceiling, not a guaranteed available limit for any specific applicant. |
| Risk 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. 3Company-reported. Company-reported advisory services on Aon’s global practice page; account-specific service scope is not stated. | Confirm in your quote. |
| How to Apply | Confirm in your quote. | 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. 6,9Company-reported. Current submission instructions and the general broker-platform workflow description; MPL-specific automation details were not separately confirmed. |
Full Comparison
More Aon vs At-Bay Comparisons
Other Professional Liability (E&O) Insurance Comparisons
Sources
Aon
- Commercial Risk Solutions U.S. Brokerage Terms of Service. Aon; Lines 120–127: certain-program broker-of-record scope, consultation, application assistance, client signature and bind instruction, and account administration; lines 140–147: variable and contingent compensation, potential placement incentive, and client request route; lines 206–213: no price guarantee and surplus-lines limitations; lines 229–231: client insurer-notice duty unless separately agreed. Accessed 2026-09-29.
- Middle Market Clients. Aon; Lines 125–132: mid-sized organizations and middle-market framing; lines 165–173: dedicated practice and North America statement; lines 188–224: Commercial Risk capabilities. No numeric company-size cutoff or U.S.-only eligibility rule is stated on the reviewed page. Accessed 2026-09-29.
- 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.
At-Bay
- Cyber, Tech E&O & Professional Liability Insurance. At-Bay; Product cards and agency disclosure. Accessed 2026-09-16.
- At-Bay Stance. At-Bay; Real Protection Against Real Threats; Endpoint, Email, MXDR; footnotes 1 and 3–6. Accessed 2026-09-16.
- 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.
- Licenses. At-Bay; Producer introduction; agency and surplus-lines footer naming At-Bay Insurance Services LLC. Accessed 2026-09-16.
- At-Bay Doubles Miscellaneous Professional Liability Appetite. At-Bay; September 28, 2023 release: final paragraph before Media Contacts. Accessed 2026-09-16.
- Broker Platform. At-Bay; How it works: Create a quote, Customize your quote, Bind your policy, Manage renewals; FAQs. Accessed 2026-09-16.
Professional Liability (E&O) Insurance Guide
- 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.
- 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.
- Get business insurance. U.S. Small Business Administration; Six common types of business insurance table. Accessed 2026-09-16.
- 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.
