---
title: "At-Bay vs USI Insurance Services Professional Liability (E&O) Insurance"
description: "USI names CNA as the underwriter of its AICPA program for CPA firms; At-Bay's current MPL page leaves the issuer unresolved."
canonical: "https://spot.insure/compare/at-bay-vs-usi/professional-errors-omissions"
page-type: "line-comparison"
updated-at: "2026-09-24"
---

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

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

USI names CNA as the underwriter of its AICPA program for CPA firms; At-Bay's current MPL page leaves the issuer unresolved.

## Research Scope and Use

Use this comparison to evaluate At-Bay 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 names CNA as the underwriter of the AICPA Professional Liability Program, which it has run as the endorsed producer for CPA firms since 1994. At-Bay's current MPL page does not name an insurer, leaving the issuer unresolved for a new quote. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite") [4](https://www.at-bay.com/licenses/ "Licenses")

## 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 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

### Who Actually Carries the Risk

USI is specific about who's on the paper for its main CPA program:

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..)

At-Bay is not, at least not on its current MPL page. It does not name the insurer that would issue a new policy, and a 2023 press release referenced a different At-Bay entity for an unrelated coverage transition. [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")

For a buyer, that's the difference between knowing the carrier before you apply and having to ask. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite") [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")


### One Profession's Program Versus a Broad Appetite

USI built the AICPA program specifically for sole practitioners and regional CPA firms, distinct from its general Business Services practice that brokers E&O for other business types. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")

At-Bay describes its own audience more broadly: businesses of all revenue sizes, without naming CPA firms or any single profession as its focus. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")

If you're not a CPA firm, USI's named program simply doesn't apply to you the way it would to an accounting practice. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")


### What You Get Beyond the Policy Itself

USI says AICPA program members also get supportive claims handling and risk-management resources, including engagement-letter templates. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")

At-Bay's page instead names mechanics built into the policy itself, like an 80/20 hammer clause and disciplinary-proceedings defense, without describing comparable risk-management extras. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")

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

- If you're a CPA firm, confirm CNA is still the underwriter on the AICPA program's current declarations. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")
- Ask At-Bay directly which insurer would issue your MPL policy. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")
- Ask USI whether your business qualifies for the AICPA program or falls under its general Business Services E&O practice instead. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")
- Ask At-Bay for its published $5 million limit ceiling and any state restrictions that apply to your business. [3](https://www.at-bay.com/insurance/mpl/ "MPL Insurance: Coverage Highlights & Appetite")
- Ask USI for specific limit, retention, or premium figures, since the AICPA program page does not publish them. [10](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")

## Offering Details

| Criteria | At-Bay Miscellaneous Professional Liability (MPL) Insurance | AICPA Professional Liability Program (USI Affinity) |
| --- | --- | --- |
| 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..) | 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 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..) | 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 | 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..) | 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 | 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..) | 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 | 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..) | 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 | Not described in the reviewed sources. | 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 | 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..) | 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

- [At-Bay vs USI Insurance Services](https://spot.insure/compare/at-bay-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.
- [At-Bay vs USI Insurance Services Cyber Insurance](https://spot.insure/compare/at-bay-vs-usi/cyber)
- [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 USI Insurance Services Professional Liability (E&O) Insurance](https://spot.insure/compare/alliance-risk-vs-usi/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.

### 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 2026-09-24. 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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