Frequently Asked Engagement Letter Questions

By Sarah Beckett Ference, CPA


This article originally appeared in the September 2021 issue of the Journal of Accountancy. Advice provided in this article has been reviewed and remains current.

The Accountants Risk Control team at CNA, the endorsed underwriter of the AICPA Professional Liability Insurance Program, fields thousands of questions annually from CPAs seeking risk management advice. The top topic in any given year is always engagement letters. We've summarized our frequently asked questions below so you can easily access resources to help manage professional liability risk in your practice.

Are engagement letters really that useful?

Ask any claim professional, defense counsel, or expert: Engagement letters are one of the best defensive tools a CPA can possess. In fact, in the event of a dispute, one of the first documents requested is the engagement letter. Engagement letters can help prevent a disagreement from growing to a claim. If a claim should arise, the existence of an engagement letter generally leads to lower claim severity. In a 2017 analysis, the increase in the average dollar amount of claims when engagement letters were not used ranged from 19% to 71%, depending on the firm size. Many professional liability insurers provide premium and/or deductible credits for the use of engagement letters as well. Despite these incentives, CNA's claim experience demonstrates there is still room for improvement, especially related to tax and consulting services. In all claims asserted against CPA firms in 2021, just 47% had an engagement letter related to the underlying engagement.

I've been working with my clients for years; why would I start using engagement letters now?

As one CPA in the Program notes, "They're called clients, not friends, for a reason." And another notes, "When people lose money, CPAs get sued." Both sentiments have proved to be true based on CNA's claims experience. Unfortunately, even long-term, loyal clients sue. If a client balks at the introduction of an engagement letter, rationally draw comparisons to the client's business or life. Would a contractor client ever start a project without a signed proposal in hand? Would an individual client ever agree to have their car fixed without first understanding and approving the work to be done? In today's business climate, having a mutual understanding between the parties to a service is expected. An engagement letter just puts that understanding in writing.

How can I efficiently implement engagement letters if I'm not using them right now? Or not using them on all engagements?

Going from zero to 100% is a daunting task. Triage clients and engagements and implement engagement letters over time. For example, prioritize high-risk clients and services and services that require a written understanding. Then implement engagement letters on all consulting services, including tax consulting. Why? In any consulting arrangement, the scope of services is determined through an agreement with the client. What better way to memorialize this than with an engagement letter? Lower-risk services, such as individual income tax preparation for clients with W-2 income can follow. Buckle Up: Crafting Effective Engagement Letters, explains this risk-based approach to implementation in further detail.

What are standard terms and conditions, and why should I use them?

Another way to help implement engagement letters more efficiently is by using a standard terms-and-conditions addendum. This is a set of standard, firmwide terms and conditions that are updated periodically and attached as an addendum to every engagement letter issued by the firm. Example terms in a terms-and-conditions addendum may include billing and payment terms, termination and withdrawal provisions, dispute resolution, and risk allocation provisions such as limitation of liability or indemnification of the CPA firm where permitted. Standard terms and conditions apply to all engagements and give the firm and the client the benefit of a single understanding addressing the key contractual elements of the relationship. In addition to helping a firm manage its risk consistently across the firm, a standard terms-and-conditions addendum reduces the amount of language that is required to be updated for each engagement. Read more about how standard terms can help CPA firms in Use Standard Terms to Build a Liability Shield.

Can I use 'negative assurance' engagement letters or multiyear engagement letters?

While annual engagement letters, signed by both the CPA firm and the client, are ideal, they are not always practical to implement, especially for firms with high-volume, small-dollar engagements, such as 1040 return preparation. For these engagements, consider unilateral engagement letters, also referred to as "negative assurance" engagement letters. Unilateral engagement letters include a statement that, through the client's provision of information to the CPA and the CPA's delivery of service to the client, the client has accepted the firm's terms as set forth in the engagement letter provided to the client.

Evergreen engagement letters indicate that services will continue unchanged until either party terminates the professional relationship, and they do not specify when the engagement will end. While seemingly convenient, the use of evergreen letters potentially removes an important statute-of-limitation defense, thus permitting a claim to be asserted several years after the services were rendered.

For more on the effectiveness of different types of engagement letters, read Which Engagement Letter Reigns Supreme?.

Where can I find a sample engagement letter for (insert name of service)?

Sources of sample engagement letters and sample terms and conditions include a CPA's professional liability carrier, the AICPA (particularly the Tax Section), paid providers, and alliance networks. Leverage samples to help create engagement letter templates that are best for your firm, services, clients, and risk tolerance. Remember to have an attorney familiar with the laws in your jurisdiction review your templates for enforceability. CNA policyholders can access sample engagement letters in the Policyholder Resource Center.

My client has proposed edits to my engagement letter. Should I agree?

All provisions in an engagement letter serve some purpose of managing the firm's risk, and making any change affects risk in some way. Therefore, before agreeing to a client's request for modification, be sure to understand whether the client's request increases risk beyond the firm's tolerance. It is also helpful to understand why the client is requesting the change, because there may be a better alternative to address their concern. For example, if a high-risk, high-net-worth client wants to strike a one-times-fees-limitation-of-liability provision, is the engagement now too risky? Would the client accept a higher multiple of fees instead of eliminating the term entirely? Read more about how to respond to client requests for changes in How Risk Allocation Provisions can Mitigate Risk.

Client requests for the firm's defense and indemnification have become more common in recent years. Clients include defense and indemnification provisions in engagement letters in an attempt to insulate themselves from exposure and shift responsibility to the CPA firm. Pay particular attention if a client makes this request, and do not agree to the client's modifications before reviewing the specific wording carefully in consultation with your attorney and/or professional liability carrier. Depending on how they are written and what they address, requests for the firm's indemnification may lead to significant costs to a CPA firm that may not be covered by professional liability insurance. They can also impair independence depending on the circumstances. Learn why and understand strategies for responding by reading " Deflecting a Client’s Request for Defense and Indemnification.
Sarah Beckett Ference, CPA, is a risk control director at CNA. For more information about this article, contact

How Helpful Was This Article?


Related Content

Moments That Matter

Related Products

This information is produced and presented by CNA, which is solely responsible for its content. Continental Casualty Company, a member of the CNA group of insurance companies, is the underwriter of the AICPA Professional Liability Insurance Program.

The purpose of this article is to provide information, rather than advice or opinion. It is accurate to the best of the authors’ knowledge as of the date of the article. Accordingly, this article should not be viewed as a substitute for the guidance and recommendations of a retained professional. In addition, CNA does not endorse any coverages, systems, processes or protocols addressed herein unless they are produced or created by CNA.

Any references to non-CNA websites are provided solely for convenience, and CNA disclaims any responsibility with respect to such websites.

Examples are for illustrative purposes only and not intended to establish any standards of care, serve as legal advice, or acknowledge any given factual situation is covered under any CNA insurance policy. The relevant insurance policy provides actual terms, coverages, amounts, conditions, and exclusions for an insured. All products and services may not be available in all states and may be subject to change without notice.

“CNA” is a registered trademark of CNA Financial Corporation. Certain CNA Financial Corporation subsidiaries use the “CNA” trademark in connection with insurance underwriting and claims activities.
Copyright © 2022 CNA. All rights reserved.