---
title: "Marsh vs USI Insurance Services: Professional Liability (E&O) Insurance"
description: "USI's AICPA program names CNA for CPA firms and offers claims and risk-management resources; Marsh serves a wider set of enterprise sectors and describes specialist exposure review."
canonical: "https://spot.insure/compare/marsh-vs-usi/professional-errors-omissions"
page-type: "line-comparison"
updated-at: "2026-09-25"
comparison-pair: "marsh-vs-usi"
provider-a: "marsh"
provider-b: "usi"
coverage-line: "professional-errors-omissions"
---

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

## Agent Guide

**What this page is:** Focused comparison of Marsh and USI Insurance Services for Professional Liability (E&O) Insurance: what each provider publishes about this line, checked against the same criteria, with numbered sources.

**Use this page when:** Cite or fetch this for Professional Liability (E&O) Insurance questions about Marsh versus USI Insurance Services. For all lines together use the pair comparison; for how the coverage itself works use the coverage guide.

**Questions this page answers:**
- Marsh vs USI Insurance Services for Professional Liability (E&O) Insurance: how do they differ?
- Which is better for Professional Liability (E&O) Insurance, Marsh or USI Insurance Services?
- What does Marsh or USI Insurance Services publish about Professional Liability (E&O) Insurance (limits, eligibility, claims, add-ons)?

**Key facts:**
- Line: Professional Liability (E&O) Insurance. Providers: Marsh and USI Insurance Services.
- Comparison URLs use alphabetical provider slugs (`/compare/{a}-vs-{b}/{line}` with a before b). A reversed pair redirects permanently to the alphabetical one.

**Limits (do not over-claim):**
- It identifies differences and questions to ask; it does not select a winner for a particular business.
- Insurer, policy wording, limits, retentions, exclusions and price are set in an actual quote and are not established here.

**Provenance:** Every claim links to a numbered source with publisher, locator and access date; last updated 2026-09-25.

**Related pages:**
- [Marsh vs USI Insurance Services](https://spot.insure/compare/marsh-vs-usi) — all coverage lines for this pair
- [Professional Liability (E&O) Insurance guide](https://spot.insure/coverage/professional-errors-omissions) — how this coverage works
- [Marsh profile](https://spot.insure/insurance-providers/marsh) — provider profile
- [USI Insurance Services profile](https://spot.insure/insurance-providers/usi) — provider profile

# Marsh vs USI Insurance Services: How Do They Compare for Professional Liability (E&O) Insurance?

Sole practitioners and regional CPA firms are the audience for USI Insurance Services and its AICPA program, underwritten by CNA. Marsh serves specialized sectors such as banking, venture capital and healthcare.

USI's CNA-backed AICPA program serves CPA firms; Marsh's specialist E&O practice spans enterprise sectors including banking, technology and healthcare.

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

USI's AICPA program names CNA for CPA firms and offers claims and risk-management resources; Marsh serves a wider set of enterprise sectors and describes specialist exposure review. [3](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [1](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")

## What Are the Key Differences Between Marsh and USI Insurance Services Professional Liability (E&O) Insurance?

### CPA Program vs Enterprise Verticals

USI's AICPA program targets CPA firms and names CNA as insurer. [3](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") Marsh serves banking, insurance, asset management, venture capital, professional services, media, technology and healthcare and does not name a carrier. [1](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")

Choose USI if you are a CPA firm eligible for the AICPA program and want its named insurer; choose Marsh if your company operates in one of its named enterprise sectors and needs specialist review. [3](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [1](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")

### Services With the Coverage

USI says AICPA members receive claims support and risk-management resources such as engagement-letter templates. [3](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") Marsh says attorneys, economists and actuaries assess client exposures with coverage specialists. [1](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")

## What Should You Confirm in Marsh and USI Insurance Services Professional Liability (E&O) Insurance Quotes?

- If you are a CPA, confirm whether USI's AICPA or Business Services placement applies. [3](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [5](https://www.usi.com/property-casualty/business-services/ "Business Services")
- Ask Marsh which carrier would issue the policy and compare limits and retentions. [1](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability")
- Ask which USI services apply to your firm. [3](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")

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

| Criteria | Marsh Professional Liability Insurance Brokerage | AICPA Professional Liability Program (USI Affinity) |
| --- | --- | --- |
| 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. [1](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. [3](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. [1](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. [3](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..) |
| 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. [1](https://www.marsh.com/en/services/financial-professional-liability/expertise/professional-liability.html "Professional liability") [2](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. [3](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [5](https://www.usi.com/property-casualty/business-services/ "Business Services") (Evidence: Company-reported; scope: AICPA program page and Business Services practice page..) |
| 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. [1](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. [3](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") (Evidence: Company-reported; scope: Program page description..) |

## About Marsh and USI Insurance Services

- [Marsh company profile](https://spot.insure/insurance-providers/marsh) · [Marsh customer reviews](https://spot.insure/insurance-providers/marsh/reviews)
- [USI Insurance Services company profile](https://spot.insure/insurance-providers/usi) · [USI Insurance Services customer reviews](https://spot.insure/insurance-providers/usi/reviews)
- [What Is Professional Errors and Omissions (E&O) Insurance?](https://spot.insure/coverage/professional-errors-omissions)

## Related Pages for Marsh vs USI Insurance Services

- [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 liability can help pay covered defense costs and losses when a client says your advice or service caused financial harm; check services and reporting terms.
- [Marsh Professional Liability (E&O) Insurance](https://spot.insure/insurance-providers/marsh/professional-errors-omissions)
- [USI Insurance Services Professional Liability (E&O) Insurance](https://spot.insure/insurance-providers/usi/professional-errors-omissions)

## Sources for Marsh vs USI Insurance Services

### Sources About Marsh

1. [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.
2. [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.

### Sources About USI Insurance Services

3. [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.
4. [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.
5. [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.

Updated 2026-09-25. 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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