Vendor-Led Diligence vs Sell-Side QoE

Executive summary

Vendor due diligence and a sell-side quality of earnings (QoE) report are both prepared at the seller's request, before buyers start their own work. They are not the same product. A sell-side QoE is a focused financial analysis: it tests reported earnings, builds an adjusted EBITDA, and usually examines net working capital and some balance sheet items. Vendor-led diligence is a broader package. It can include the financial analysis and add commercial, operational, tax, technology, or people sections, depending on what the seller expects buyers to ask.

The choice is a trade between speed, control, and credibility. A seller that commissions work first can find problems before a buyer does, shorten the buyer's process, and anchor the discussion on its own numbers. The cost is that buyers know the report was commissioned by the seller, so they will test it, and some will do their own work regardless. A report that is thin, aggressive, or surprised by the buyer's questions can hurt more than no report.

This guide helps a seller decide which to commission and how to prepare, and helps a buyer decide how much weight to give what arrives in the data room. The terms of any engagement, including who may rely on the report and what liability the provider accepts, are set in the engagement letter and any reliance letter. Counsel and your advisers must review those documents. Nothing here is legal or accounting advice.

When to use this

Use this guide when:

• You are preparing to sell a company and want to decide whether to commission work before launching a process.
• You are running an auction with several bidders and want them working from one set of facts.
• You are a buyer's operator receiving a vendor report and deciding how far to rely on it.
• Your earnings have adjustments, such as one-time costs, owner expenses, or a recent acquisition, that need support before buyers see them.
• A prior attempt to sell stalled because buyers could not agree on the earnings base.

If you are still two or more years from a sale, the exit readiness 24-month plan is a better starting point, because the work that makes a vendor report credible takes time.

The difference in plain terms

Terminology varies by firm and by market. Some providers use "vendor due diligence" for any seller-commissioned report, including a sell-side QoE. Read the scope section of the proposal rather than the label, and ask the provider to list the workstreams, the data used, the period covered, and what is excluded.

Diagnostic questions

Answer these before you ask for proposals. They determine which product fits.

1. Are reported earnings and adjusted earnings far enough apart that a buyer will challenge the bridge?
2. Can you produce monthly financial statements for the last 36 months that reconcile to the audited or reviewed annual numbers?
3. Which questions did buyers or lenders ask in prior conversations, and were they about earnings, customers, operations, or something else?
4. How concentrated is revenue, and can you show customer retention and pricing history cleanly?
5. Is there a large capital project, system migration, or restructuring in the period that buyers will question?
6. Does the business have a seasonal or lumpy net working capital pattern that will complicate the peg? See working capital peg in M&A.
7. How many credible buyers do you expect, and would a single shared report save work for all of them?
8. Do you have the finance capacity to support a diligence project alongside running the business?
9. Is the likely buyer a strategic acquirer, which may do its own commercial work, or a financial buyer that will lean more on third-party reports?
10. What would you do if the report found something that lowers adjusted earnings, and are you prepared to disclose it?
11. Do you need the report to be usable by lenders, and if so, what do they require?

Question 10 matters more than the others. A seller who commissions work must be willing to accept the result. If the plan is to commission a report only if it is favorable, the process will leak that intent.

The framework: choose by gap, not by habit

A simple way to choose is to compare the questions buyers will ask with the evidence you can already show.

Start with the earnings and working capital rows. Those drive price and the peg, and nearly every buyer will test them. Add other sections only where a specific, predictable buyer question has no good answer in your files. Each additional workstream costs management time, and every finding becomes a topic in the negotiation.

What a buyer should do with a vendor report

A report from the seller's side is useful, and it is also written from the seller's side. Treat it as a map, not a conclusion.

1. Read the scope and the exclusions first. What periods, entities, and data did the provider use? What did it not test?
2. Check who the report is addressed to and what the reliance terms say. Ask counsel what rights, if any, you have against the provider, and whether a reliance letter is available.
3. Re-perform the high-value adjustments. Pick the largest add-backs and removals and test each against source documents.
4. Test the net working capital series against your own cut of the monthly balance sheets, using the same definition you expect in the agreement.
5. Look for what is missing. If the report has no section on customer concentration or inventory valuation, ask why.
6. Ask for the provider's call. A direct conversation with the team that did the work usually reveals the judgment calls that never reached the page.
7. Decide the remaining scope. Use the report to shorten your own work, not to remove it. The financial due diligence checklist lists what a buyer still needs to cover.

Worked example (illustrative)

The figures below are invented to show how a bridge is read. They are not benchmarks.

A seller reports EBITDA of $6.00M. The sell-side QoE proposes four adjustments:

Check: 6.00 + 0.40 + 0.30 − 0.20 + 0.25 = 6.75.

A buyer's team re-performs the bridge and disagrees with three items. It rejects half of the owner compensation add-back because a replacement manager would be needed (0.20), trims the price run-rate for customers likely to leave (0.15), and removes a further 0.15 for a recurring cost the seller treated as one-time:

Check: 6.75 − 0.35 − 0.15 = 6.25.

At an assumed 8.0 times multiple (illustrative only), the seller's view implies 6.75 × 8.0 = $54.0M and the buyer's view 6.25 × 8.0 = $50.0M. The gap is $4.0M, which is 0.50M of EBITDA multiplied by 8.0.

What this tells the operator:

• A vendor report does not remove disagreement. It narrows it to specific, documented items, which is faster to resolve than a general dispute about "quality."
• Each add-back with a document behind it (the settlement agreement, the payroll records) was easier to defend than the ones that required a judgment about the future.
• The seller who had thought through the owner compensation question before the buyer raised it could offer a compromise with a rationale instead of defending a position.
• The multiple is a separate negotiation. The bridge decides the earnings base, and the base is multiplied by whatever multiple the parties reach.

Step-by-step process

The seller should expect to answer more questions, not fewer, in the first weeks of the process. The benefit is that the answers are consistent and documented.

Templates

Provider scope comparison (copy into a spreadsheet)

Adjustment support register

Buyer's read-through checklist

1. Scope, periods, entities, and exclusions understood.
2. Addressee and reliance terms reviewed by counsel.
3. Three largest adjustments re-performed from source.
4. Net working capital series reconciled to monthly balance sheets.
5. Missing topics listed and raised with the provider.
6. Remaining diligence scope agreed with the deal team.

Metrics and KPIs

Targets by method. There is no correct adjustment ratio to copy from another company. Use your own prior-year bridge as the anchor, then set a goal that a larger share of adjustments carries a source document than last time. Track how many buyer questions the report answered before they asked, and how far the final agreed EBITDA moved from the report figure. A small movement suggests the report was credible; a large one tells you which judgments to prepare better next time.

Common mistakes

1. Commissioning work without readiness. If monthly statements do not reconcile to the annual numbers, the provider will spend its time fixing that, and the report will carry caveats that buyers read as warnings.
2. Choosing the broadest scope by default. More sections mean more findings and more management time. Match the scope to predictable buyer questions.
3. Selling the report as a conclusion. Buyers will re-perform it. Present it as supported analysis that makes their work faster.
4. Aggressive add-backs. One unsupported adjustment puts every other adjustment under suspicion. Lead with the documented ones.
5. Ignoring the engagement terms. Who may rely on the report, and what the provider accepts liability for, are legal questions. Counsel should read the engagement letter and any reliance letter before signing.
6. Letting the report go stale. A report on trailing numbers loses value as months pass. Plan for updates through signing.
7. Buyers accepting it unread. A buyer who skips re-performance inherits the seller's judgments without the ability to challenge them later.
8. No management response. If management has no considered answer to a finding, the buyer will supply its own.

AI prompt assistance

AI can help prepare the analysis and organize questions. It cannot give a view on reliance or liability; that belongs with counsel. Supply your own data and verify the output.

1. Draft an adjustment register from a ledger extract.

I will paste a list of candidate EBITDA adjustments with amounts, descriptions, and source document names. Build a table with columns: adjustment, amount, direction, recurring or one-time, source document, judgment level (high, medium, low), and the most likely buyer challenge. Do not add adjustments I did not list.

Check: confirm each amount and document name against the source, and review the judgment ratings with your CFO.

2. Prepare a Q&A log from buyer questions.

Here are 30 buyer questions from three management meetings. Group them into earnings, working capital, commercial, operations, technology, and other. For each group, list what evidence a vendor report would need to answer them.

Check: have the deal lead confirm the grouping and note which questions need a document, not a narrative.

3. Compare provider proposals.

I will paste the scope sections of three diligence proposals. Fill in this comparison table (pasted) using only what the proposals say. Where a proposal is silent, write "not stated" rather than inferring.

Check: read each "not stated" cell with the provider, and send reliance and liability terms to counsel.

Implementation guide

These durations vary by company size and scope; treat them as a planning structure, not a promise.

Governance: the CEO owns the objective, the CFO owns the numbers, counsel owns the engagement and reliance terms, and the provider owns its own conclusions. Management should not edit the provider's findings; it should respond to them in writing.

Downloadable assets

The provider scope comparison, adjustment support register, and buyer's read-through checklist are designed to be copied into a spreadsheet. If your diligence includes a working capital section, the working capital peg estimator can help you test the series before you commission work.

Related resources

• Due diligence hub: all diligence guides in one place.
• Quality of earnings report before you close: how a QoE is built and read.
• Financial due diligence checklist: what a buyer still needs to cover.
• Working capital peg in M&A: how the working capital section feeds the price mechanics.
• Commercial due diligence red flags and operational due diligence checklist: the sections a broader vendor package may add.
• Technology due diligence for operators and people and organization due diligence: the remaining workstreams.

Frequently asked questions

What is the difference between vendor due diligence and a sell-side QoE?

A sell-side QoE is a focused financial analysis of earnings and net working capital, while vendor due diligence is a broader seller-commissioned package that can add commercial, operational, tax, and technology sections. Providers use the terms differently, so compare the written scope, periods, and exclusions rather than the label.

Should a seller commission a vendor report before a sale?

A seller should commission one when buyers will predictably challenge earnings or working capital and the seller can support its position with documents. It is less useful if monthly statements do not reconcile yet, or if the seller would suppress an unfavorable result. Fix readiness first and decide with your advisers.

Will buyers rely on a seller's report?

Buyers usually treat a vendor report as a starting point and re-perform the largest items. Whether a buyer may rely on it legally depends on the engagement letter and any reliance letter. Ask counsel to review those terms, and do not assume reliance exists because the report is in the data room.

How should a buyer test a sell-side QoE?

Start with the scope and exclusions, then re-perform the three largest adjustments from source documents and reconcile the working capital series to the monthly balance sheets. Ask what topics are missing and speak to the provider's team. Use the report to shorten your own work, not to replace it.

How long does vendor due diligence take?

Duration depends on scope, data readiness, and management capacity, so ask each provider for a written timeline tied to the data it needs from you. Most delays come from reconciling monthly statements and supporting adjustments, which is why a readiness review should come before the engagement, not after.

How this works in a System of Performance

A vendor report is only as strong as the records behind each adjustment, and most companies assemble them under deadline. A Performis routine can take on a recurring job like this, with the scope and fit agreed with you: it works from the records your team supplies, prepares the work for your named reviewer, and keeps each approval on record. To see where your own earnings base is well documented and where it is not, bring it to us as a launch partner.