We Explain Attest & Nonattest Services. Which One Is Right For Your Business?

  • Contributors:
  • Brandi Clark-Hubbard
Audit team planning attest services in office

When hiring a public accounting firm to provide audit services, do you understand all the service options and how they might benefit your organization? What’s the difference between an audit, an examination, a review, and a compilation? When should you pick one over the other? What will you gain from each type of engagement? In this post, we answer these questions, define attest and nonattest services, and break down the types of services within each category.

Attest Services

Attest (or attestation) services can cover a broad range of financial or nonfinancial objectives based on the users’ needs. Auditors evaluate subject matter or an assertion in accordance with specific criteria. Attest engagements include assurance and non-assurance services. Most importantly, attest services are a set of protected services that only licensed certified public accountants (CPA) who operate within a CPA firm can perform. Why?  

Licensed CPAs have the right degree of expertise, education, and regulatory oversight to conduct attest engagements following standards issued by the American Institute of Certified Public Accountants (AICPA). CPAs must be independent on all attest engagements. 

In addition, they’re required to participate in ongoing education requirements and peer review efforts and comply with a professional code of conduct. Each of these factors ensures that the CPA profession is appropriately regulated and CPAs deliver high-quality services.  

If you choose to engage an audit firm for an attest service, you can be confident that the CPAs have the credentials and resources to do the job well.  

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Assurance Services

Assurance services fall within the larger category of attest services. When providing assurance services, a CPA issues a report that expresses his/her opinion on the subject matter. The goal of an assurance service is to enhance decision-makers’ confidence in specific information, such as financial statements or security controls. Therefore, CPAs perform procedures to test the credibility of information. These procedures may include inquiries, observations, or more detailed testing. 

In Michigan, three engagements fall under the umbrella of attest and assurance services: audits, reviews, and examinations.

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Audits provide the highest level of assurance. The purpose of an audit is to provide financial statement users with an opinion on whether the financial statements are presented fairly, in all material respects, according to the applicable reporting framework. Financial statement audits are subject to generally accepted auditing standards (GAAS) issued by the AICPA. 

During an audit, CPAs perform procedures to obtain reasonable assurance that financial statements are free from material misstatement. The auditor may conduct physical inspections, make inquiries, request third-party confirmations, make observations, and take other actions they deem necessary to obtain this assurance. 

Once procedures are complete, CPAs will issue a formal report letter attached to the financial statements. The report expresses an opinion on whether the information is presented fairly in accordance with the applicable financial reporting framework. And, CPAs must issue a separate report on any internal control deficiencies they discover that rise to the level of a significant deficiency or material weakness. 

Many companies need an audit when applying for financing or credit, looking for outside investors, or preparing to sell or merge. The auditor’s report gives each party more confidence in the accuracy of the information and allows them to make a more informed decision.  

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Read our blog post: 11 Different Types Of Audits That Can Help Your Business



An examination achieves the same level of assurance – reasonable assurance – as an audit. However, CPAs examine business matters, not financial statements. When conducting an examination, a CPA obtains reasonable assurance by gathering sufficient evidence to evaluate the subject matter against criteria. Then, the CPA offers a written opinion on whether the subject matter complies with the criteria in all material respects.  

Examples of business matters that could be subject to examination include security and privacy controls, sustainability, compliance with rules/regulations, and greenhouse gases. 

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According to the AICPA, “the review is the base level of CPA assurance services.” CPAs provide limited assurance to the end-users of the reviewed information. The scope of a review is much narrower than an audit or examination. 

During a review, the CPA performs analytical procedures and inquiries to obtain sufficient evidence to support their conclusion. Once the review is complete, the CPA will issue a report that states whether they’re aware of any material adjustments that need to be made so that records comply with the applicable criteria or to ensure the information is fairly stated. They also describe their process so users have the context to understand the conclusion. 

Many privately-held companies provide financial statements to outside parties, and therefore, require reviews. You may want a review if your business is growing and needs additional financing or credit. Or, you may want to evaluate an aspect of your business on its overall accuracy to make key decisions. Again, CPAs commonly review financial statements, but you could also request a review of the physical characteristics of facilities or human resource practices.  

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Non-Assurance Services

When CPAs perform non-assurance services, they issue a report, but it doesn’t include their opinion or conclusion on the subject matter they evaluated. Non-assurance services can fall within the umbrella of attest engagements. Agreed-upon procedures engagements are a type of non-assurance service.

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Agreed-Upon Procedures

An agreed-upon procedures (AUP) engagement is when a CPA conducts a select set of procedures. The CPA works with the client and/or related parties to identify and verify the procedures, performs them, then issues a report on their findings. The CPA doesn’t provide their opinion or conclusion in the report. The client is responsible for reviewing the report and drawing their own conclusions based on the CPA’s findings.  

Why would you want an AUP? If you don’t need a full audit, AUPs are great options! You get the benefit of an independent professional conducting audit-like procedures. You can design procedures to evaluate financial or nonfinancial subjects. You can review the report and make your own decisions. It’s less rigorous than an audit but specific enough to gain a better understanding of the subject matter.  

Examples of agreed-upon procedures include verifying cash balances, evaluating the validity of credit card transactions, and confirming the sales and profits of an entity. As with all attest services, the CPA you hire to conduct agreed-upon procedures must be licensed, work for a licensed CPA firm, and be independent.

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Nonattest Services

Nonattest services differ from attest engagements because CPAs don’t express opinions, conclusions, or findings. They cover a broad range of accounting services, such as financial statement preparation, compilations, cash to accrual conversions, tax return preparation, advisory services, forensic accounting, and more!  

Both CPAs and non-CPAs can perform nonattest services, but CPAs follow more rigorous reporting standards as members of professional accounting associations. If a CPA provides an attest service to a client, they should evaluate their independence before beginning a nonattest service. If their independence is impaired by performing a nonattest service, they should resolve the independence issue or decline the job.  

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CPAs use their expertise to help management prepare and present the company’s financial statements. The CPA doesn’t perform any procedures to obtain assurance on the validity of the information in the financial statements.  

Simply put, management collects and shares the required financial information with the CPA. The CPA compiles the information and shares the results in the form of financial statements. If the CPA finds significant issues, they’ll communicate them to management to make necessary corrections before issuing an accountant’s compilation report letter. 

You may request a compilation for your business to obtain financing or credit or when you don’t have the resources to properly prepare financial statements. 

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Each of these services add value to your business, but you can maximize the benefit by selecting the service that aligns with your business goals, needs, and any third-party requirements. If you need help finding the right service for your business or are ready to hire qualified CPAs for the job, look no further! The accountants at Beene Garter, A Doeren Mayhew Firm are here to help you.