An engagement letter for a tax audit is the written contract between you and the professional representing you before the IRS, and a good one nails down five things: who you are and which returns are under exam, exactly what the representative will do, what it costs, how sensitive decisions like statute extensions get handled, and how the relationship ends. Circular 230, the federal rule governing practice before the IRS, expects tax advisors to reach a clear understanding with clients on the form and scope of the work before it begins.1eCFR. 31 CFR 10.33 – Best Practices for Tax Advisors Everything below is what a careful reader should look for before signing.
Identifying You and the Returns Under Exam
The letter opens with your full legal name and taxpayer identification number — a Social Security Number for an individual, an Employer Identification Number for a business.2Internal Revenue Service. Instructions for Form 1120 It should name the specific tax forms being examined, whether that’s Form 1040, Form 1120, or another return, so representation is limited to filings actually under audit.3Internal Revenue Service. About Form 1120, U.S. Corporation Income Tax Return
Just as important, the letter lists the exact tax years or periods the IRS notice covers. Check each detail against that notice before you sign. A mismatched year or a wrong taxpayer ID delays authorization and forces the representative to sort things out with the IRS before they can do anything useful.
What the Representative Will and Won’t Do
The scope section is where most disputes start, so it deserves close reading. Standard audit representation usually covers responding to Information Document Requests (the IRS’s formal method for demanding your financial records and supporting evidence), communicating with the auditor, attending scheduled meetings, reviewing proposed adjustments, and explaining your positions with documentation.4Internal Revenue Service. IRM 4.46.4 Executing the Examination – Section: Information Document Request Process IDRs can reach bank statements, receipts, contracts, and internal accounting records.5Internal Revenue Service. Navigating the IDR Process
Look for the boundary. Most engagement letters cover you only through the examiner’s final determination. If the outcome is unfavorable and you want to file a formal protest with the IRS Appeals Office or petition the U.S. Tax Court, that work sits outside the original contract and requires a separate engagement letter or a written amendment.6Internal Revenue Service. Appeals Process Without that clarity, you can end up assuming coverage that was never agreed to at the moment you most need it.
Fees and Billing
The financial terms should be specific enough that no invoice surprises you. Most audit representatives bill hourly. CPAs handling audit work generally charge between $200 and $450 per hour. Tax attorneys range from roughly $400 for a solo practitioner to $850 or more at an established firm. Enrolled agents often fall at the lower end of the CPA range. Complexity matters too: a correspondence audit costs far less than a field examination touching multiple entities.
Some professionals offer flat fees for narrowly defined audits, which gives you cost certainty but limits flexibility if the audit expands. Others require a retainer deposited into a trust account, drawn down as work is performed. For hourly arrangements, the letter should state the billing increment, usually six or fifteen minutes.
Beyond professional fees, expect language on reimbursable expenses: certified mail, copying, travel to in-person meetings, and similar administrative costs. If the audit calls for outside specialists such as appraisers, engineers, or industry experts, the letter should say whether those costs fall on you and whether the representative will seek your approval before hiring them. The billing cycle (typically monthly invoices due within 30 days) and consequences for late payment complete this section.
Authority Over Statute of Limitations Extensions
This is the provision most taxpayers overlook, and it can matter more than fees. During an examination, the IRS often asks you to sign Form 872, which extends the time the agency has to assess additional tax against you.7Internal Revenue Service. IRM 25.6.22 Extension of Assessment Statute of Limitations by Consent Without an extension, the IRS must wrap up within the normal assessment period, generally three years from filing. Signing buys both sides more time and gives the IRS a longer window to come after you.
The letter should address whether the representative may advise you on these extensions and whether they can sign a consent form on your behalf. Signing authority itself flows through Form 2848, but the engagement letter sets the expectation. The IRS is required to explain your rights each time it asks for an extension:
- You can refuse to extend the assessment period entirely.
- You can request that the extension apply only to specific issues rather than your whole return.
- You can request an extension that runs only to a specific date rather than remaining open-ended.
Watch for Form 872-A. Unlike the standard Form 872 that expires on a set date, Form 872-A stays in effect indefinitely until either side files Form 872-T to terminate it, after which the IRS has 90 days to complete its assessment.7Internal Revenue Service. IRM 25.6.22 Extension of Assessment Statute of Limitations by Consent A good engagement letter addresses the representative’s ongoing duty to monitor an open-ended consent and advise you when to terminate. Signing a Form 872-A without that understanding leaves you exposed far longer than necessary.
Conflicts of Interest, Especially When the Preparer Defends the Return
A common situation: the same professional who prepared the return is now being asked to defend it. That creates an inherent tension, because the representative has a personal interest in showing the original work was correct. Under 31 C.F.R. §10.29, a practitioner cannot represent you if a conflict exists unless three conditions are met: the practitioner reasonably believes they can still provide competent, diligent representation; the representation is not otherwise prohibited by law; and you waive the conflict in writing within 30 days of when the practitioner identifies it. The practitioner must keep that written consent for at least 36 months after the representation ends and produce it to the IRS on request.8eCFR. 31 CFR 10.29 – Conflicting Interests
If the firm that prepared your return hands you an engagement letter with no conflict disclosure at all, that omission is worth questioning. The conflict may be manageable, but skipping the disclosure violates the federal rule.
What You Owe the Representative
The letter is not one-sided. Your core obligation is providing complete and accurate information, because the entire defense is built on the documents and explanations you supply. The letter typically makes clear that you bear responsibility for the accuracy of what you hand over.
Expect a requirement to respond to your representative’s requests within a reasonable time. IRS deadlines don’t move because you were slow. The letter will also state that no particular outcome is guaranteed. An audit representative works to minimize your liability, but no ethical practitioner promises a specific result, and that language protects you from relying on a promise nobody can keep.
Data Security and Record Retention
During an audit you turn over deeply sensitive information: returns, bank statements, payroll records, Social Security numbers. Tax preparation firms are classified as financial institutions under the FTC Safeguards Rule and must maintain a written information security program covering administrative, technical, and physical safeguards, along with breach notification if your data is compromised.9Federal Trade Commission. FTC Safeguards Rule: What Your Business Needs to Know The engagement letter should describe how those safeguards apply to your file.
Record retention deserves its own paragraph. The IRS generally has three years from filing to examine a return, six years when income is understated by more than 25 percent, and no time limit for fraud or unfiled returns, so keeping your own supporting documents at least six years covers the common extended scenarios.10Internal Revenue Service. Good Recordkeeping Year-Round Helps Taxpayers Avoid Tax Time Frustration The letter should say how long the representative keeps a copy of the audit file and what happens to your documents when the engagement ends: returned, securely destroyed, or archived.
Ending the Engagement
No one signs expecting the relationship to fall apart, but the letter needs to say how it ends if it does. You might lose confidence in the strategy or be unable to keep paying. The representative might need to withdraw if you stop cooperating, withhold critical documents, or ask them to take a position they consider unethical. Circular 230 also requires practitioners to possess the competence — the knowledge, skill, thoroughness, and preparation — the matter demands.11eCFR. 31 CFR 10.35 – Competence If a routine small-business audit turns into an international transfer pricing issue, the representative may need to bring in help or withdraw.
The termination clause should spell out how much notice each side owes the other, what happens to any retainer balance, and how the representative will avoid leaving you unrepresented at a critical point in the exam.
Signing the Letter and Filing Form 2848
Once you’ve reviewed every provision, sign. Most representatives accept electronic signatures through secure platforms; some still require ink. Either way, the signature activates the agreement.
Signing the engagement letter is not the same as authorizing representation with the IRS. That requires Form 2848, Power of Attorney and Declaration of Representative, which gives your professional legal authority to act on your behalf before the IRS, including receiving your confidential tax information, communicating with agents, and signing agreements.12Internal Revenue Service. About Form 2848, Power of Attorney and Declaration of Representative Only individuals eligible to practice before the IRS — attorneys, CPAs, enrolled agents, and certain other qualified professionals — can be named on Form 2848.13Internal Revenue Service. Publication 947 – Practice Before the IRS and Power of Attorney
The form can be submitted online, by fax, or by mail, and the IRS processes submissions in the order received.14Internal Revenue Service. Submit Forms 2848 and 8821 Online Once processed, the authorization is recorded in the IRS’s Centralized Authorization File, and audit correspondence goes to your representative’s office rather than to you.15Internal Revenue Service. Form 2848 – Power of Attorney and Declaration of Representative File it as soon as the engagement letter is signed. The sooner the IRS recognizes your representative, the less likely you are to face audit mail you’re not sure how to handle.