Aon vs 
Markel Insurance: How Do They Compare for Professional Liability (E&O) Insurance?
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
Markel Insurance: Specialty Business and Products
Markel Insurance is Markel Group's specialty and small-business insurance business, with offerings across packages, workers' compensation, cyber, professional and management liability, property, marine, and surety. Products use different insurers and distribution routes, so compare the issuer and terms shown on the specific quote. 4,5
Read the Markel Insurance profile
Read the Markel Insurance Professional Liability (E&O) Insurance page
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. 7,8,9,10
Key Differences in Professional Liability (E&O) Insurance
Professional Class and Product Scope
Aon says it tailors professional-liability structures to the needs of firms in law, accounting and consulting, but does not publish a limit. Markel describes miscellaneous E&O for small businesses in targeted industries and states coverage up to $2 million. Markel labels that figure a product maximum, not a promise for every applicant. Buyers can use it as a ceiling to discuss, then ask both firms what limit and retention fit the services and client contracts at issue. 3 6
Placement Detail and Buyer Decisions
Markel invites prospective customers or brokers to contact its underwriting team and says terms depend on the issued policy and jurisdiction. Aon likewise acts as a broker/adviser and does not name the carrier for a placement. Markel’s reviewed overview separates E&O from management liability but gives limited detail about covered acts. Request the specific form, exclusions, retroactive date and issuing insurer from both providers before comparing the $2 million headline with an actual quote. 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 reviewsMarkel Insurance
Review Score
2 rated sources
There is little public customer feedback on Markel. Trustpilot shows 2.5 out of 5 from just 5 reviews, and BBB lists 12 complaints closed in the last three years.[4][3]
Read Markel Insurance reviewsOffering Details
Aon vs Markel Insurance: Professional Liability (E&O) Insurance: documented features by provider
| Criteria | Aon Professional Liability / E&O brokerage and risk-advisory offering | Markel professional errors omissions (official overview) |
|---|---|---|
| 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. | Markel describes offering professional errors omissions for the audience stated on the cited product page. 6Company-reported. professional errors omissions marketed by markel; scope is limited to the cited official product overview and described audience. This is not a policy form or a universal eligibility statement. |
| 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. | Confirm in your quote. |
| 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. | Small businesses in ProBiz's targeted industries; source describes businesses up to $5 million revenue for the miscellaneous E&O product. 6Company-reported. professional errors omissions marketed by markel; scope is limited to the cited official product overview and described audience. This is not a policy form or a universal eligibility statement. |
| 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. | The cited product page describes miscellaneous E&O for covered claims arising from professional services, with the page describing separate E&O and management-liability products. Marketing description only; actual coverage, exclusions, conditions, limits, and availability depend on the issued policy and jurisdiction. 6Company-reported. professional errors omissions marketed by markel; scope is limited to the cited official product overview and described audience. This is not a policy form or a universal eligibility statement. |
| 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. | For its miscellaneous E&O product, Markel states coverage up to $2 million; this is a product-page maximum, not a promise that every applicant or quote receives that amount. 6Company-reported. Markel ProBiz miscellaneous E&O marketing page; class, underwriting, policy terms, and actual quoted limit control. |
| 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. | The page invites prospective customers or brokers to contact Markel or the named underwriting team. The page does not establish a quote, bind, or coverage-effective timeline. 6Company-reported. professional errors omissions marketed by markel; scope is limited to the cited official product overview and described audience. This is not a policy form or a universal eligibility statement. |
Full Comparison
More Aon vs Markel Insurance 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.
Markel Insurance
- About us. Markel; Markel at a glance; description of Markel Insurance within Markel Group Inc. Accessed 2026-09-28.
- Markel Group Inc. 2025 Form 10-K. U.S. Securities and Exchange Commission; filed by Markel Group Inc.; Cover page; Part I, Item 1 Business—Markel Insurance, U.S. Wholesale and Specialty, Programs and Solutions; Part II, Item 7/8 for group and segment risks. Accessed 2026-09-28.
- ProBiz | Professional Liability Coverage. Markel; Miscellaneous E&O; types of covered professional-service errors; ProBiz target classes and process. Accessed 2026-09-30.
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.
