---
title: "Marsh vs USI Insurance Services Professional Liability (E&O) Insurance"
description: "USI names CNA as underwriter for its AICPA-endorsed CPA program; Marsh's broader professional liability practice doesn't name an insurer."
canonical: "https://spot.insure/compare/marsh-vs-usi/professional-errors-omissions"
page-type: "line-comparison"
updated-at: "2026-09-23"
---

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[Human-readable page](https://spot.insure/compare/marsh-vs-usi/professional-errors-omissions)

# Marsh vs USI Insurance Services Professional Liability (E&O) Insurance

USI names CNA as underwriter for its AICPA-endorsed CPA program; Marsh's broader professional liability practice doesn't name an insurer.

## Research Scope and Use

Use this comparison to evaluate Marsh and USI Insurance Services 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

USI's AICPA Professional Liability Program is underwritten by CNA for CPA firms specifically, while Marsh's professional and financial liability practice places E&O across named enterprise industries without naming a carrier. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [5](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")

## 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. [1](https://www.marsh.com/en/home.html "Marsh | Leader in risk, strategy, people, and investments") [2](https://www.marsh.com/content/dam/marsh/Documents/PDF/US-en/us-client-compensation-guide.pdf "Compensation guide for US clients") [3](https://www.marsh.com/en/services/marsh-mclennan-agency.html "Marsh McLennan Agency (MMA)") [4](https://www.marsh.com/en/industries/technology.html "Technology | Insurance Broking & Risk Management")

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

## What Is USI Insurance Services?

USI Insurance Services is a U.S. insurance brokerage and consulting firm that arranges property and casualty, employee benefits, personal risk, and retirement programs. Its Technology practice says it works with software, hardware, and related companies from early seed stage through IPO, using a consultative process rather than a published self-serve quote. [7](https://www.usi.com/about-usi "The Power of ONE") [8](https://www.usi.com/property-casualty/technology/ "Technology Insurance") [9](https://www.usi.com/commissions-fees/ "Commissions and Fees")

[USI Insurance Services profile](https://spot.insure/insurance-providers/usi)

## 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

### A Named Insurer for One Program

USI's page names a carrier for its AICPA-endorsed program specifically. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") Marsh's professional liability and MMA executive-and-professional-liability pages do not name a specific insurer for the coverage they place. [5](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") [6](https://www.marshmma.com/us/solutions/executive-and-professional-liability.html "Expert Executive and Professional Liability Insurance")

### A Decades-Old CPA Program Versus Named Enterprise Industries

USI's page describes a relationship built around one profession over decades:

USI markets the AICPA program to sole practitioners and regional CPA firms. It has offered CPA coverage since 1967 and has been the endorsed AICPA Program provider since 1994. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") (Evidence: Company-reported; scope: Program page description..)

Marsh instead names a set of enterprise verticals — banking, insurance companies and asset managers, venture capital, accountants, attorneys, architects and engineers, media, technology, and healthcare and biotechnology — rather than a single long-running profession-specific program. [5](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")

### Services Bundled With the Policy

USI's page says AICPA program enrollees get supportive claims handling and exclusive access to risk-management resources, including engagement-letter templates. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") Marsh's page instead describes staffing its practice with attorneys, economists and actuaries to assess exposure, a different kind of service layer than USI's claims-handling and template resources. [5](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")

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

- If you're a CPA firm, ask USI whether you'd be placed in the CNA-underwritten AICPA program or a different market. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")
- Ask Marsh which insurer it intends to place your policy with, since its pages don't name one. [5](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")
- Ask USI whether the AICPA program's risk-management resources extend to its general Business Services E&O placements outside the CPA program. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")
- Neither page publishes limits or retentions for these placements; get both in writing. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [5](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")

## Offering Details

| Criteria | Marsh Professional Liability Insurance Brokerage | AICPA Professional Liability Program (USI Affinity) |
| --- | --- | --- |
| Role in This Line | 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. [5](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") [6](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..) | For CPA firms, USI runs the AICPA Professional Liability Program through its USI Affinity division as the endorsed producer, rather than underwriting the policy itself. USI's general Business Services practice separately brokers errors and omissions/professional liability coverage for other business types. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [12](https://www.usi.com/property-casualty/business-services/ "Business Services") (Evidence: Company-reported; scope: AICPA program page and Business Services practice page..) |
| Issuing Insurer | The reviewed pages do not name a specific professional liability insurer. [5](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") [6](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..) | USI's own page states that the AICPA Professional Liability Program is "underwritten by CNA," naming the carrier for that specific program. USI's general Business Services E&O placements do not name an insurer. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") (Evidence: Company-reported; scope: Direct quote from the AICPA program page; CNA underwrites only this named program, not USI's other professional-liability placements..) |
| Who It’s For | 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. [5](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..) | USI markets the AICPA program to sole practitioners and regional CPA firms. It has offered CPA coverage since 1967 and has been the endorsed AICPA Program provider since 1994. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") (Evidence: Company-reported; scope: Program page description..) |
| Coverage Features | 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. [5](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..) | USI describes the policy as insuring a CPA and their practice against third-party claims that professional services caused financial harm, providing a defense and paying damages for covered claims arising from high-risk situations tied to new clients, changing business plans, or new laws and regulations. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") (Evidence: Company-reported; scope: Program page description; actual insuring agreements, exclusions and conditions are set by the issued CNA policy form..) |
| Limits and Retentions | Not described in the reviewed sources. | The AICPA program page does not publish limit, retention or premium figures; it says coverage plans allow a firm to tailor coverage to its risk profile. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") (Evidence: Not publicly disclosed; scope: Page as read on 2026-09-23..) |
| Risk Services | 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. [5](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") (Evidence: Company-reported; scope: Marsh professional liability page..) | USI says firms enrolled in the program get supportive claims handling and exclusive access to risk-management resources, including engagement-letter templates, in addition to the coverage itself. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") (Evidence: Company-reported; scope: Program page description..) |
| How to Apply | Not described in the reviewed sources. | USI directs CPA firms seeking a quote or renewal to contact USI Affinity, with a dedicated Affinity_APL@usi.com address for the AICPA program specifically. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") (Evidence: Company-reported; scope: Contact instructions on the AICPA program page..) |

## Full Comparison

- [Marsh vs USI Insurance Services](https://spot.insure/compare/marsh-vs-usi): 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.
- [Marsh vs USI Insurance Services Commercial Property Insurance](https://spot.insure/compare/marsh-vs-usi/commercial-property)
- [Marsh vs USI Insurance Services Crime Insurance](https://spot.insure/compare/marsh-vs-usi/crime)
- [Marsh vs USI Insurance Services Cyber Insurance](https://spot.insure/compare/marsh-vs-usi/cyber)
- [Marsh vs USI Insurance Services D&O Insurance](https://spot.insure/compare/marsh-vs-usi/directors-officers)
- [Marsh vs USI Insurance Services Employee Health Benefits](https://spot.insure/compare/marsh-vs-usi/employee-health-benefits)
- [Marsh vs USI Insurance Services Employment Practices Liability Insurance](https://spot.insure/compare/marsh-vs-usi/employment-practices)
- [Marsh vs USI Insurance Services Fiduciary Liability Insurance](https://spot.insure/compare/marsh-vs-usi/fiduciary)
- [Marsh vs USI Insurance Services Management Liability Insurance](https://spot.insure/compare/marsh-vs-usi/management-liability)
- [Marsh vs USI Insurance Services Surety Bonds](https://spot.insure/compare/marsh-vs-usi/surety-bonds)
- [Marsh vs USI Insurance Services Workers’ Compensation Insurance](https://spot.insure/compare/marsh-vs-usi/workers-compensation)
- [Alliance Risk vs Marsh Professional Liability (E&O) Insurance](https://spot.insure/compare/alliance-risk-vs-marsh/professional-errors-omissions)
- [Alliance Risk vs USI Insurance Services Professional Liability (E&O) Insurance](https://spot.insure/compare/alliance-risk-vs-usi/professional-errors-omissions)
- [At-Bay vs Marsh Professional Liability (E&O) Insurance](https://spot.insure/compare/at-bay-vs-marsh/professional-errors-omissions)
- [At-Bay vs USI Insurance Services Professional Liability (E&O) Insurance](https://spot.insure/compare/at-bay-vs-usi/professional-errors-omissions)
- [Beazley vs Marsh Professional Liability (E&O) Insurance](https://spot.insure/compare/beazley-vs-marsh/professional-errors-omissions)
- [Beazley vs USI Insurance Services Professional Liability (E&O) Insurance](https://spot.insure/compare/beazley-vs-usi/professional-errors-omissions)

## Sources

### Marsh

1. [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.
2. [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.
3. [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.
4. [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.
5. [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.
6. [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.

### USI Insurance Services

7. [The Power of ONE](https://www.usi.com/about-usi). USI Insurance Services; History, client-count, nationwide office, and P&C / benefits / personal risk / retirement description. Accessed 2026-09-16.
8. [Technology Insurance](https://www.usi.com/property-casualty/technology/). USI Insurance Services; Technology practice client types, seed-to-IPO range, and listed insurance placement lines including PrivaSafe. Accessed 2026-09-16.
9. [Commissions and Fees](https://www.usi.com/commissions-fees/). USI Insurance Services; Licensed-producer authority, insurer-paid commission default, contingent compensation, and client request right. Accessed 2026-09-16.
10. [Accountants Professional Liability — USI Affinity](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/). USI Insurance Services; Quality Professional Liability Insurance Exclusively for CPA Firms; "The AICPA Professional Liability Program, underwritten by CNA, has been offering coverage to CPAs since 1967 and has been the endorsed provider of the AICPA Program since 1994."; supportive claims handling and exclusive access to extensive risk management resources, including engagement letter templates; Email Affinity_APL@usi.com. Accessed 2026-09-23.
11. [USI Specialty Program Solutions](https://www.usi.com/programs/). USI Insurance Services; USI Affinity delivers high-quality insurance and financial solutions to members of affinity organizations and targeted industry segments...for professional associations, law firms, alumni and collegiate organizations, travel groups, and insurance administrators.. Accessed 2026-09-23.
12. [Business Services](https://www.usi.com/property-casualty/business-services/). USI Insurance Services; USI advises clients...and provides solutions for...Errors & Omissions/Professional Liability.... 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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