Engagement letter is the written agreement identifying the professional service provider, client, service scope, responsibilities, deliverables, fees, and other terms governing a particular accounting engagement.
Why is the engagement letter an acquisition document?
It documents promised services and agreed payment terms. That evidence helps a buyer evaluate revenue, staffing, risk, and the relationship it intends to continue.
The seller’s revenue schedule might describe monthly bookkeeping, while the client expects payroll support, annual tax work, management advice, and help with notices inside the same fee. A letter that clearly separates services makes that discrepancy easier to detect. An old letter with a broad description may leave the buyer dependent on interviews and workpapers to reconstruct the scope.
Connect the review to the valuation hub. Earnings supported by an understood service obligation are easier to underwrite than billings whose delivery burden remains uncertain. The letter is evidence for that analysis; it does not guarantee client retention or collectability.
What should the buyer inspect in each letter?
Inspect the identity, scope, timing, client duties, fee mechanism, termination terms, and other material conditions. Read amendments and incorporated terms with the base document.
The April 2026 Journal of Accountancy CAS engagement-letter guidance recommends specific scope, responsibilities, deliverables, fees, and documented changes. That professional guidance supports a practical acquisition review without implying that one standard letter fits every service line.
Confirm whether the agreement identifies the same entity that invoices and performs the work. Look for stale dates, unsigned versions, side emails, and schedules that modify the fee or scope. Record what is missing rather than assuming the seller’s customary practice is a binding client obligation. Questions about validity, assignment, and required consent belong with the transaction’s qualified legal and professional reviewers.
How can the letters be organized for diligence?
Create a client-level index that links each material engagement to its current governing documents and unresolved issues. The index should be useful for pricing and the later service handoff.
| Field | Evidence | Buyer decision supported |
|---|---|---|
| Service provider | Named entity and signing professional | Determine the intended successor arrangement |
| Service scope | Included work and exclusions | Budget delivery hours and skills |
| Frequency | Monthly, quarterly, annual, or project schedule | Plan deadlines and capacity |
| Fees | Fixed, hourly, contingent, or other approved terms | Reconcile expected billing |
| Client responsibilities | Information, approvals, and management duties | Identify dependencies and delays |
| Transition conditions | Assignment, renewal, termination, and consent terms | Plan relationship documentation |
Use coded identifiers where appropriate and control access to full documents under applicable confidentiality and data rules.
Does a signed letter prove the revenue will continue?
No. It describes the agreed relationship and terms, but the buyer must also evaluate actual performance, payment, renewal, and the client’s choices under those terms.
A letter may permit cancellation, expire before closing, or cover work already completed. A client may have tolerated a longstanding service issue because of the seller’s personal involvement. The buyer needs evidence of what has happened in practice: invoices, collections, scope changes, complaints, staffing, and upcoming obligations.
The recurring versus one-time revenue framework helps distinguish cadence from durable demand. A monthly invoice for a six-month cleanup project differs from a continuing service arrangement, even if both have signed letters. Confirm the remaining term and actual purpose before classifying the fee as recurring.
How can undocumented scope affect earnings?
It can create delivery costs that the seller’s financial presentation does not make clear. Compare promised work, work actually delivered, and the buyer’s proposed capacity.
Assume an illustrative monthly engagement pays $2,000, or $24,000 annually. The documented budget allows 20 hours monthly, while interviews and work records indicate 30 hours are regularly required. At an assumed incremental loaded labor cost of $60 per hour, the extra 10 hours cost $600 monthly, or $7,200 annually.
The resulting $16,800 before other allocated costs is not the engagement’s final profit. It simply reconciles fee revenue less the incremental scope burden in this example. Test whether the work is included, separately billable, avoidable, or in need of a new agreement. Do not count a hypothetical fee increase as established earnings before client acceptance and delivery evidence support it.
What does the buyer do when the letter and work disagree?
Investigate the discrepancy and document the operating obligation before pricing or changing the relationship. Neither the narrow letter nor the broad oral description should be treated as complete evidence by itself.
The Journal of Accountancy’s April 2026 professional documentation discussion emphasizes alignment between scope, work performed, and the deliverable. For acquisition diligence, inspect workpapers, recurring reports, change emails, and meeting notes to understand that alignment. Do not repeat an insurance case example as evidence about the practice being purchased.
Determine whether additional tasks are an authorized scope change, a temporary accommodation, or an unresolved client expectation. The buyer may need a revised service plan, fee discussion, or remediation budget. Assign an owner for the client conversation and record the decision. Staff should receive the agreed scope so the discrepancy does not reappear immediately after closing.
How should new or updated letters be introduced?
Introduce them as part of a coordinated service conversation, with appropriate review of assignment, consent, and professional requirements. The transaction’s legal form does not by itself establish that every engagement transfers unchanged.
- Confirm the current service agreement and the intended post-closing provider.
- Identify assignment, renewal, consent, or replacement-document requirements.
- Reconcile promised scope with the buyer’s actual delivery plan and fee proposal.
- Explain the service arrangement to the client through an approved transition sequence.
- Track completed documentation and resolve clients with open questions before affected work proceeds.
Sequence changes carefully. A purchaser introducing a new name, team, portal, billing method, and fee at once should understand how those changes interact with client readiness and deadlines. The letter should describe the actual arrangement the buyer can deliver, not an aspirational service package that staff have not been equipped to perform.
How do working papers and client-file transfers relate to the letter?
The engagement agreement helps establish the relationship, while record access and transfer have their own legal and professional considerations. Do not assume a newly signed letter resolves every predecessor-record issue.
The May 2025 Journal of Accountancy working-paper transition guidance discusses predecessor and successor responsibilities and recommends addressing file transfer, retention, access, and costs in the transaction agreement. Keep that record plan connected to client documentation and the actual data being moved.
For tax information, review Section 7216 client consent and applicable exceptions separately. A general service agreement may not meet a specific consent requirement. Also identify which records the seller must retain or access for future questions. The operating team needs a lawful method to obtain needed history without making every legacy record freely available.
How should fee changes be separated from the ownership announcement?
Explain both clearly, but do not conceal a fee change inside a routine notice of ownership. The client needs to understand the service, price, timing, and choices in the new arrangement.
Distinguish continuation on existing terms from an approved expansion or revised package. If the buyer expects to improve reporting, identify the deliverables and implementation date. If the acquired fee is insufficient for the existing scope, budget the effect of the proposed repricing and potential client response rather than assuming every increase will be accepted.
A letter can make the commercial discussion more concrete by showing included tasks, exclusions, and how additional work is approved. Keep client communications consistent with the agreement and the practice’s actual billing setup. When several staff members interact with the client, they should know which terms apply and who can authorize exceptions.
What should the buyer maintain after the transition?
Maintain an accessible current agreement, amendments, scope decisions, and responsibility record for each engagement. Acquisition diligence should become an operating resource instead of a static archive.
The transition agreement can assign the seller’s assistance with explaining historical scope and introducing the successor team. It should also identify who owns the relationship after the handoff. A client should not receive conflicting instructions from the retiring owner and the new engagement leader.
Review agreements when services, deliverables, entities, or material terms change. Align the index with billing and staffing records to detect work outside scope.
A few common questions
What else should you know?
Does an engagement letter transfer automatically when the practice sells?
Do not assume automatic transfer. Review the agreement, transaction structure, applicable law, and professional requirements to determine whether assignment, consent, renewal, or replacement documentation is needed. Confirm the actual post-closing provider and service arrangement. The commercial purchase of a client relationship does not itself answer every contractual question.
What if the seller has no current engagement letters?
Record the gap and reconstruct material scope, fees, responsibilities, and expectations using available records and appropriate discussions. Have qualified reviewers assess contractual and professional implications. The buyer should create a controlled documentation plan for continuing work and reflect unresolved scope or cost in diligence rather than assuming standard terms.
Can a new letter justify a planned fee increase in valuation?
A proposed letter does not establish realized earnings. Model the fee change as an assumption until acceptance and delivery evidence support it. Consider scope, implementation cost, timing, and possible client response. Separate existing revenue from projected repricing so the buyer and lender can evaluate the acquisition’s supported base case.
Is an engagement letter the same as Section 7216 consent?
No. The engagement letter governs the service relationship, while an applicable Section 7216 consent authorizes specified disclosure or use of tax return information under particular requirements. Coordinate both documents when needed, but do not assume a general engagement clause supplies every tax-information authorization or resolves record-transfer obligations.
Which sources support this guide?
Primary rules and guidance support the factual statements in this article. The worked examples and decision frameworks are original educational analysis.
- Tips for writing CAS engagement letters — Journal of Accountancy
- Liability lessons on documentation and CAS engagement letters — Journal of Accountancy
- Changes at the firm? What to do with working papers — Journal of Accountancy