---
title: "At-Bay vs Marsh Professional Liability (E&O) Insurance"
description: "Marsh names specialized industry practices for professional liability; At-Bay's MPL page publishes a $5 million limit ceiling instead."
canonical: "https://spot.insure/compare/at-bay-vs-marsh/professional-errors-omissions"
page-type: "line-comparison"
updated-at: "2026-09-23"
---

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# At-Bay vs Marsh Professional Liability (E&O) Insurance

Marsh names specialized industry practices for professional liability; At-Bay's MPL page publishes a $5 million limit ceiling instead.

## Research Scope and Use

Use this comparison to evaluate At-Bay and Marsh for Professional Liability (E&O) Insurance against the same documented criteria. It identifies differences and questions to confirm; it does not select a winner for a particular business. Offering claims are what each provider publishes about this line unless marked otherwise. “Not found” describes the evidence reviewed, not proof that a feature is unavailable. Confirm the insurer, policy wording, limits, retentions, exclusions and cost in an actual quote.

## Summary

Marsh names specialized industries its professional liability experts serve, from banking and asset managers to healthcare and biotechnology. At-Bay publishes a single $5 million limit ceiling for Miscellaneous Professional Liability across the businesses it accepts. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")

## What Is At-Bay Insurance?

At-Bay offers Cyber, Tech E&O, and miscellaneous professional liability insurance through its disclosed insurance agency and surplus lines broker. Its Stance security services have policy eligibility conditions, with managed detection and response sold separately. [1](https://www.at-bay.com/insurance/ "Cyber, Tech E&O & Professional Liability Insurance") [2](https://www.at-bay.com/stance/ "At-Bay Stance")

[At-Bay profile](https://spot.insure/insurance-providers/at-bay)

## What Is Marsh?

Marsh is a global insurance broker and risk advisor. In the United States it places coverage through core Marsh teams and through Marsh McLennan Agency for many middle-market buyers, including technology, cyber, property, casualty and benefits programs. [7](https://www.marsh.com/en/home.html "Marsh | Leader in risk, strategy, people, and investments") [8](https://www.marsh.com/content/dam/marsh/Documents/PDF/US-en/us-client-compensation-guide.pdf "Compensation guide for US clients") [9](https://www.marsh.com/en/services/marsh-mclennan-agency.html "Marsh McLennan Agency (MMA)") [10](https://www.marsh.com/en/industries/technology.html "Technology | Insurance Broking & Risk Management")

[Marsh profile](https://spot.insure/insurance-providers/marsh)

## What Is Professional Errors and Omissions (E&O) Insurance?

Professional errors and omissions (E&O) insurance, also called professional liability insurance, addresses claims that professional services or advice caused a client financial loss. What's covered depends on the services actually scheduled in the policy, not the product label alone. [13](https://www.tdi.texas.gov/commercial/pl-faq.html "FAQ: Professional liability insurance") [14](https://www.iii.org/article/professional-liability-insurance "Professional liability insurance") [15](https://www.sba.gov/counseling/launch-your-business/#business-insurance "Get business insurance") [16](https://www.hiscox.com/documents/pl-sample-policy-wording.pdf "Professional Liability – US Direct Errors and Omissions Insurance")

## Key Differences in Professional Liability (E&O) Insurance

### Named Industry Specialties Versus a General Appetite

Marsh names specialized industries its professional liability practice serves: banking and broker/dealers, insurance companies and asset managers, venture capital, accountants, attorneys, architects and engineers, media, technology, and healthcare and biotechnology. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") At-Bay's MPL page instead describes eligibility in general terms, businesses of all revenue sizes, and points to a separate appetite guide for the specifics. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")

### Named Specialist Staff Versus a Named Product Feature

Marsh says it employs attorneys, economists, and actuaries alongside coverage specialists to assess a client's professional-liability exposure given the complexity of these risks. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") At-Bay does not describe comparable in-house specialist staff on its MPL page, focusing instead on listed policy features like the duty-to-defend contract and hammer clause. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")

### What Neither Page Names

Marsh's reviewed pages do not name a specific professional liability insurer for a given placement. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") At-Bay's current MPL page similarly does not name the insurer that would issue a new policy. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")

## What to Confirm in Professional Liability (E&O) Insurance Quotes

- Ask Marsh which of its named industry specialties applies to your business and what that means for underwriting access. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")
- Ask At-Bay for its published $5 million limit ceiling and applicable state restrictions. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")
- Ask both companies to name the insurer that would actually issue your policy. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")
- Ask Marsh which specialists — attorneys, economists, or actuaries — would be involved in assessing your specific risk. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")
- Confirm whether At-Bay requires submission through a licensed insurance professional for your business. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")

## Offering Details

| Criteria | At-Bay Miscellaneous Professional Liability (MPL) Insurance | Marsh Professional Liability Insurance Brokerage |
| --- | --- | --- |
| Role in This Line | 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. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite") [4](https://www.at-bay.com/licenses/ "Licenses") (Evidence: Company-reported; scope: Current MPL product page and license disclosures; this describes the distribution channel, not who bears the underwriting risk..) | Marsh's financial and professional liability practice places professional liability (errors and omissions) insurance; MMA also places E&O coverage within its executive and professional liability practice for middle-market clients. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") [12](https://www.marshmma.com/us/solutions/executive-and-professional-liability.html "Expert Executive and Professional Liability Insurance") (Evidence: Company-reported; scope: Marsh professional liability page and MMA executive and professional liability page..) |
| Issuing 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. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite") [5](https://www.at-bay.com/press_releases/at-bay-doubles-mpl/ "At-Bay Doubles Miscellaneous Professional Liability Appetite") (Evidence: Not found in reviewed sources; scope: 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..) | The reviewed pages do not name a specific professional liability insurer. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") [12](https://www.marshmma.com/us/solutions/executive-and-professional-liability.html "Expert Executive and Professional Liability Insurance") (Evidence: Not publicly disclosed; scope: Marsh professional liability page and MMA executive and professional liability page as read on 2026-09-23..) |
| Who It’s For | 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. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite") (Evidence: Company-reported; scope: Current MPL appetite paragraph; the linked appetite guide's specific eligibility requirements were not independently opened for this record..) | Marsh names specialized industries its professional liability experts serve, including banking and broker/dealers, insurance companies and asset managers, merchant banking and venture capital, accountants, attorneys, architects and engineers, media and entertainment, technology, and healthcare and biotechnology. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") (Evidence: Company-reported; scope: Marsh professional liability page, What We Offer section..) |
| Coverage Features | 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. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite") (Evidence: Company-reported; scope: 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..) | Marsh says professional liability coverage can protect a company against liability and defense costs from a claim alleging an error, omission or negligence in performing professional services, and that many policies also cover privacy violations and computer security breaches. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") (Evidence: Company-reported; scope: Marsh professional liability page opening description; illustrative policy description, not a specific policy form..) |
| Limits and Retentions | At-Bay publishes an MPL limit ceiling of up to $5 million, with state restrictions that are not detailed on the product page itself. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite") (Evidence: Company-reported; scope: Current appetite paragraph; this is an advertised ceiling, not a guaranteed available limit for any specific applicant..) | Not described in the reviewed sources. |
| Risk Services | Not described in the reviewed sources. | Marsh says it employs attorneys, economists and actuaries alongside coverage specialists to assess a client's professional liability exposure from multiple angles, given the complexity of these risks. [11](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") (Evidence: Company-reported; scope: Marsh professional liability page..) |
| How to Apply | 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. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite") [6](https://www.at-bay.com/brokers/platform/ "Broker Platform") (Evidence: Company-reported; scope: Current submission instructions and the general broker-platform workflow description; MPL-specific automation details were not separately confirmed..) | Not described in the reviewed sources. |

## Full Comparison

- [At-Bay vs Marsh](https://spot.insure/compare/at-bay-vs-marsh): all coverage lines, business roles, service and claims.
- [What Is Professional Errors and Omissions (E&O) Insurance?](https://spot.insure/coverage/professional-errors-omissions): Professional E&O insurance addresses claims that a mistake in your advice or services caused a client financial loss.
- [At-Bay vs Marsh Cyber Insurance](https://spot.insure/compare/at-bay-vs-marsh/cyber)
- [At-Bay vs Marsh Tech E&O Insurance](https://spot.insure/compare/at-bay-vs-marsh/technology-errors-omissions)
- [Alliance Risk vs At-Bay Professional Liability (E&O) Insurance](https://spot.insure/compare/alliance-risk-vs-at-bay/professional-errors-omissions)
- [Alliance Risk vs Marsh Professional Liability (E&O) Insurance](https://spot.insure/compare/alliance-risk-vs-marsh/professional-errors-omissions)
- [At-Bay vs Beazley Professional Liability (E&O) Insurance](https://spot.insure/compare/at-bay-vs-beazley/professional-errors-omissions)
- [At-Bay vs CFC Professional Liability (E&O) Insurance](https://spot.insure/compare/at-bay-vs-cfc/professional-errors-omissions)
- [At-Bay vs Chubb Professional Liability (E&O) Insurance](https://spot.insure/compare/at-bay-vs-chubb/professional-errors-omissions)
- [At-Bay vs Coalition Professional Liability (E&O) Insurance](https://spot.insure/compare/at-bay-vs-coalition/professional-errors-omissions)

## Sources

### At-Bay

1. [Cyber, Tech E&O & Professional Liability Insurance](https://www.at-bay.com/insurance/). At-Bay; Product cards and agency disclosure. Accessed 2026-09-16.
2. [At-Bay Stance](https://www.at-bay.com/stance/). At-Bay; Real Protection Against Real Threats; Endpoint, Email, MXDR; footnotes 1 and 3–6. Accessed 2026-09-16.
3. [MPL Insurance: Coverage Highlights & Appetite](https://www.at-bay.com/insurance/mpl/). 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.
4. [Licenses](https://www.at-bay.com/licenses/). At-Bay; Producer introduction; agency and surplus-lines footer naming At-Bay Insurance Services LLC. Accessed 2026-09-16.
5. [At-Bay Doubles Miscellaneous Professional Liability Appetite](https://www.at-bay.com/press_releases/at-bay-doubles-mpl/). At-Bay; September 28, 2023 release: final paragraph before Media Contacts. Accessed 2026-09-16.
6. [Broker Platform](https://www.at-bay.com/brokers/platform/). At-Bay; How it works: Create a quote, Customize your quote, Bind your policy, Manage renewals; FAQs. Accessed 2026-09-16.

### Marsh

7. [Marsh | Leader in risk, strategy, people, and investments](https://www.marsh.com/en/home.html). Marsh; Hero and capability tiles; FAQ: What does Marsh do?; industries served; Is Marsh the same as Marsh McLennan? January 2026 brand change. Accessed 2026-09-16.
8. [Compensation guide for US clients](https://www.marsh.com/content/dam/marsh/Documents/PDF/US-en/us-client-compensation-guide.pdf). Marsh; US broking segments; broker role; retail commissions, client fees, wholesale, insurer consulting, contingent and supplemental commissions; Marsh LLC and Marsh USA LLC; page 3: broker role and Marsh & McLennan Agency segment; page 7: copyright © 2024 Marsh LLC. Accessed 2026-09-16.
9. [Marsh McLennan Agency (MMA)](https://www.marsh.com/en/services/marsh-mclennan-agency.html). Marsh; Middle-market US organizations; wholly-owned subsidiary; business insurance, employee health and benefits, retirement, private client. Accessed 2026-09-16.
10. [Technology | Insurance Broking & Risk Management](https://www.marsh.com/en/industries/technology.html). Marsh; Opening Technology Practice description; practice links including data center insurance, fintech and Stratus; Talk to us. Accessed 2026-09-16.
11. [Professional liability](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html). Marsh; Opening description; What We Offer: specialized industries served (banking, insurance/asset managers, merchant banking/venture capital, accountants/attorneys/architects/engineers, media/communications/entertainment, technology, healthcare/biotechnology). Accessed 2026-09-23.
12. [Expert Executive and Professional Liability Insurance](https://www.marshmma.com/us/solutions/executive-and-professional-liability.html). Marsh McLennan Agency; Our policies include D&O, E&O, EPL, commercial crime/fidelity, network security privacy risk/cyber, fiduciary, media liability, IP, architects and engineers, lawyers professional, and kidnap and ransom. Accessed 2026-09-23.

### Professional Liability (E&O) Insurance Guide

13. [FAQ: Professional liability insurance](https://www.tdi.texas.gov/commercial/pl-faq.html). 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.
14. [Professional liability insurance](https://www.iii.org/article/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.
15. [Get business insurance](https://www.sba.gov/counseling/launch-your-business/#business-insurance). U.S. Small Business Administration; Six common types of business insurance table. Accessed 2026-09-16.
16. [Professional Liability – US Direct Errors and Omissions Insurance](https://www.hiscox.com/documents/pl-sample-policy-wording.pdf). 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.

Updated 2026-09-23. Spot, a product of Tools for Enlightenment, publishes this research and works in the commercial insurance market. The comparison applies the same criteria to both providers. [Editorial policy](https://spot.insure/editorial-policy). To suggest a correction, [contact Spot](https://spot.insure/contact) with the page URL and supporting source.

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