---
title: "Harper vs USI Insurance Services: Professional Liability (E&O) Insurance"
description: "USI's AICPA Professional Liability Program is underwritten by CNA for CPA firms specifically, while Harper writes a generalized E&O policy across professions without naming an insurer."
canonical: "https://spot.insure/compare/harper-vs-usi/professional-errors-omissions"
page-type: "line-comparison"
updated-at: "2026-09-25"
comparison-pair: "harper-vs-usi"
provider-a: "harper"
provider-b: "usi"
coverage-line: "professional-errors-omissions"
---

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

## Agent Guide

**What this page is:** Focused comparison of Harper 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 Harper 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:**
- Harper vs USI Insurance Services for Professional Liability (E&O) Insurance: how do they differ?
- Which is better for Professional Liability (E&O) Insurance, Harper or USI Insurance Services?
- What does Harper 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: Harper 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:**
- [Harper vs USI Insurance Services](https://spot.insure/compare/harper-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
- [Harper profile](https://spot.insure/insurance-providers/harper) — provider profile
- [USI Insurance Services profile](https://spot.insure/insurance-providers/usi) — provider profile

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

A CPA firm can use USI Insurance Services, which runs the AICPA program, underwritten by CNA, with engagement-letter templates included. Harper, a broker, targets consultants, agencies and tech firms.

USI's AICPA program serves CPA firms; Harper tailors professional liability to client contracts and says it can issue a required certificate the same day.

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

USI's AICPA Professional Liability Program is underwritten by CNA for CPA firms specifically, while Harper writes a generalized E&O policy across professions without naming an insurer. [4](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance")

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

### A Named Insurer, but Only for One Client Type

USI's own page states its AICPA Professional Liability Program is "underwritten by CNA," naming a carrier, but only for the CPA firms that qualify for the AICPA-endorsed program; USI's separate Business Services practice brokers E&O for other business types without naming an insurer there:

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. [4](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..)

Harper's reviewed pages name pricing drivers such as services performed and revenue but do not disclose an issuing insurer or a limit figure for the generalized policy it places. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance")

### Who Each Policy Is Built For

USI's AICPA program has been the endorsed provider for CPAs and their firms since 1994 and has offered accountant coverage since 1967, so its named-insurer advantage is specific to that one profession. [4](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") Harper instead writes its policy around the applicant's actual services for consultants, agencies, tech firms and other licensed professionals generally, rather than through a professional-association endorsement. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance")

### What Comes With the Policy

USI says AICPA program firms get supportive claims handling plus exclusive risk-management resources, including engagement-letter templates, alongside the coverage itself. [4](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") Harper's differentiator is a described pre-purchase review: it says it reads a policy's exclusions line by line before a client buys, since two E&O policies with the same limit can respond differently to the same claim. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance")

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

- If you're a CPA firm, confirm you qualify for USI's AICPA-endorsed, CNA-underwritten program rather than its general Business Services E&O placement. [4](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity")
- Ask Harper for the issuing insurer and policy limit, since neither appears on its reviewed pages. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance")
- Ask USI which risk-management resources apply outside the AICPA program if you're not a CPA firm. [6](https://www.usi.com/property-casualty/business-services/ "Business Services")
- Ask Harper which exclusions its review flagged for your specific services. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance")

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

| Criteria | Harper Professional Liability Insurance | AICPA Professional Liability Program (USI Affinity) |
| --- | --- | --- |
| Who It’s For | Harper targets consultants, agencies, tech firms and licensed professionals whose work product is advice, design or a decision, since general liability doesn't cover a client claiming that work caused a financial loss. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance") (Evidence: Company-reported; scope: Professional liability page introduction and FAQ distinguishing it from general liability..) | 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. [4](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 | You request a quote online or by phone; if a client contract requires E&O, Harper says it places coverage matching that requirement and issues the certificate the same day. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance") (Evidence: Company-reported; scope: Professional liability page quote form and FAQ 'My client contract requires E&O. What now?'..) | 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. [4](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..) |
| Coverage Features | Harper describes coverage for errors and omissions in the work itself, negligence allegations about professional judgment, and legal defense costs, with limits it says are matched to the client contracts that require the policy. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance") [2](https://www.harperinsure.com/coverages/errors-and-omissions "Errors and Omissions Insurance") (Evidence: Company-reported; scope: Professional liability page's four coverage tiles; the E&O page adds that claims often surface a year or more after the work was delivered. The issued policy and its exclusions control actual scope..) | 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. [4](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 | Harper places professional liability coverage as a broker, writing the policy around the applicant's actual services rather than underwriting it, and describes a specialist handling the placement. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance") (Evidence: Company-reported; scope: Professional liability page introduction and 'Why Harper' section..)<br><br>Harper markets the identical policy under two catalogue entries, "Professional Liability" and "Errors and Omissions"; the E&O page states it is the same policy, just named what a given industry calls it. [2](https://www.harperinsure.com/coverages/errors-and-omissions "Errors and Omissions Insurance") [3](https://www.harperinsure.com/coverages "What We Cover") (Evidence: Company-reported; scope: Coverage directory listing plus the E&O page's own description; a naming convention Harper states about itself, not a distinction between two products..) | 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. [4](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") [6](https://www.usi.com/property-casualty/business-services/ "Business Services") (Evidence: Company-reported; scope: AICPA program page and Business Services practice page..) |
| Risk Services | Harper says it reads a policy's exclusions line by line before a client buys, because two E&O policies with the same limit can respond very differently to the same claim. [1](https://www.harperinsure.com/coverages/professional-liability "Professional Liability Insurance") (Evidence: Company-reported; scope: Professional liability page 'We know this' section; a described review practice, not an independently verified outcome..) | 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. [4](https://www.usi.com/programs/affinity-programs/accountants-professional-liability/ "Accountants Professional Liability — USI Affinity") (Evidence: Company-reported; scope: Program page description..) |

## About Harper and USI Insurance Services

- [Harper company profile](https://spot.insure/insurance-providers/harper) · [Harper customer reviews](https://spot.insure/insurance-providers/harper/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 Harper vs USI Insurance Services

- [Harper vs USI Insurance Services](https://spot.insure/compare/harper-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.
- [Harper Professional Liability (E&O) Insurance](https://spot.insure/insurance-providers/harper/professional-errors-omissions)
- [USI Insurance Services Professional Liability (E&O) Insurance](https://spot.insure/insurance-providers/usi/professional-errors-omissions)

## Sources for Harper vs USI Insurance Services

### Sources About Harper

1. [Professional Liability Insurance](https://www.harperinsure.com/coverages/professional-liability). Harper; Know your coverage: What is Professional Liability insurance?; Errors & omissions, Negligence allegations, Legal defense, Contract-driven limits; Why Harper; FAQs on general liability vs. E&O, client E&O requirements, and pricing drivers. Accessed 2026-09-23.
2. [Errors and Omissions Insurance](https://www.harperinsure.com/coverages/errors-and-omissions). Harper; Page states the product is 'Same policy as professional liability, just what your industry calls it'; describes financial-loss claims from professional services and late-arriving claims. Accessed 2026-09-23.
3. [What We Cover](https://www.harperinsure.com/coverages). Harper; Coverage directory list including Errors and Omissions and Professional Liability as separate catalogue entries. Accessed 2026-09-23.

### Sources About USI Insurance Services

4. [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.
5. [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.
6. [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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