Most investment mistakes do not happen because the business was bad. They happen because the right questions were never asked. A data room is opened, the financials are ticked against audited accounts, compliance certificates are collected, and the deal moves on. The report is thick, but the real risks were never tested. This article sets out the ten mistakes we see most often in buy-side due diligence, what each one typically costs, and how to design a review that challenges the story rather than confirming it.
The most common due diligence mistakes are treating the exercise as a checklist, relying on reported profit without testing cash, accepting audited estimates without challenge, ignoring trading after the last balance sheet, using management data without independent reconciliation, overlooking concentration and management behaviour, keeping scope too narrow, and failing to convert findings into price, terms and protections.
Why does due diligence turn into a checklist exercise?
Checklists are useful. They make sure nothing basic is forgotten: statutory registers, tax returns, loan agreements, licences. The problem starts when completing the checklist becomes the objective.
Three pressures push diligence in that direction. Deal timelines are tight and the team wants to close. The seller controls the data room and naturally presents the business favourably. And once an investor is emotionally committed to a deal, there is a quiet tendency to look for comfort rather than risk.
If every finding in a draft report reads 'no exceptions noted', ask what was actually tested. A review that only confirms documents exist has not yet asked whether the business is what it appears to be.
Good diligence starts from the opposite assumption: every important number is a claim, and each claim needs independent evidence and an explanation of why it will continue.
The ten most common due diligence mistakes
1. Focusing on reported profit and not on cash
Profit is an accounting result; cash is evidence. When EBITDA rises every year but operating cash flow does not, the gap is usually explained by receivables, inventory or revenue timing. A proof-of-cash exercise, reconciling bank receipts to reported sales, is one of the fastest ways to test whether earnings are real. See our guide on cash flow vs profit and proof of cash.
2. Treating audited numbers as unquestionable
Audited statements rest on judgements: provisions for bad debts and inventory, capitalisation of costs, useful lives, revenue cut-off. These are acceptable within a range. Diligence should ask where in that range management has chosen to sit, and whether a buyer would choose differently.
3. Stopping at the last audited balance sheet
Deals are often signed six months or more after the last audit. Current trading, monthly management accounts and the order book for that stub period frequently tell a different story from the audited year.
4. Using management data without independent reconciliation
Customer-wise sales, ageing reports and product margins usually come from management spreadsheets. They should be reconciled to the ledger, GST returns, bank statements and the Annual Information Statement before any analysis relies on them.
5. Ignoring concentration and dependency
A small number of customers, suppliers or people can carry a disproportionate share of the business. This rarely appears as a red flag in financial statements and has to be built up from ledgers and contracts.
6. Overlooking management behaviour
Delayed answers, disclosures made only on direct questioning and shifting assumptions are information. They should be recorded and weighed, not dismissed as personality.
7. Keeping the scope too narrow
A purely financial review can miss tax disputes, pending litigation, guarantees given for group companies, charges registered with the Registrar of Companies, and regulatory licences with conditions attached.
8. Not testing revenue recognition
Bill-and-hold arrangements, year-end channel stuffing, and recognition before performance obligations are satisfied can all flatter the base year. Our article on revenue recognition in due diligence explains the tests.
9. Failing to translate findings into the deal documents
A risk identified in the report but not reflected in price, working capital mechanism, conditions precedent or indemnities has been noticed, not managed.
10. Starting too late
When diligence begins after the price is effectively agreed, findings become negotiating friction instead of inputs to valuation. The investor then accepts more risk to protect the timeline.
What each mistake typically costs, and the better practice
| Mistake | Typical consequence | Better practice |
|---|---|---|
| Profit without cash | Paying for earnings that never convert to cash | Proof of cash; EBITDA to operating cash flow bridge |
| Unchallenged estimates | Base-year EBITDA overstated by provision or capitalisation choices | Re-perform key estimates using buyer assumptions |
| Ignoring stub period | Valuing a business on a year that has already passed | Review monthly results and order book up to signing |
| Unreconciled management data | Analysis built on numbers that do not tie to records | Reconcile to ledger, GST returns, AIS and bank statements |
| Narrow scope | Tax, legal and guarantee exposures discovered after closing | Coordinated financial, tax and legal workstreams |
| Findings not in SPA | Known risks borne by the buyer | Map every finding to price, peg, CP, indemnity or escrow |
The pattern is consistent: the mistake is rarely a lack of documents. It is a lack of challenge, and a failure to carry each finding through to a commercial consequence.
Illustrative example: the cost of ignoring current trading
An investor agrees to value a company at 7x EBITDA based on audited FY 2025-26 EBITDA of Rs 12 crore, implying an enterprise value of Rs 84 crore. Signing is planned for October 2026. Diligence that stops at 31 March 2026 reports no issues.
A review of monthly accounts for April to September 2026 shows EBITDA of Rs 4.2 crore, against Rs 6 crore for the same six months of the previous year, because a major contract was repriced. Last-twelve-month EBITDA is therefore Rs 12 crore minus Rs 6 crore plus Rs 4.2 crore, or Rs 10.2 crore.
At the same 7x multiple, enterprise value on last-twelve-month EBITDA is Rs 71.4 crore, Rs 12.6 crore lower than the price based on the audited year. The audited figure was accurate; it was simply out of date.
How to design due diligence that challenges rather than confirms
- Write the investment thesis down first. List the three to five assumptions the valuation depends on, such as growth rate, margin, customer retention and capex needs. Diligence should test each one directly.
- Agree a hypothesis-led scope. For each assumption, define what evidence would confirm it and what would break it, and allocate it to the financial, tax or legal workstream.
- Insist on source data. Request ledgers, GST returns, bank statements and contracts, not only summaries prepared for the data room.
- Cover the period up to signing. Include monthly results, current order book and post-balance-sheet events, and refresh key numbers before completion.
- Interview more than one person. Speak separately to the promoter, finance head, sales lead and operations lead, and compare answers.
- Quantify every finding. Convert each issue into an effect on EBITDA, net debt, working capital or one-time cost.
- Close the loop into the SPA. Before signing, check that every material finding has a home in price, working capital mechanism, conditions precedent, specific indemnity or escrow.
For how working capital findings feed into the purchase price mechanism, see our article on the working capital peg in due diligence.
Questions that separate real diligence from box-ticking
The quality of diligence is not measured by the number of documents reviewed. It is measured by whether each key assumption in the valuation has been tested and either confirmed, adjusted or protected against.
Frequently asked questions
What is the biggest mistake in due diligence?
Treating it as a confirmation exercise. When the review only checks that documents exist and numbers agree with audited accounts, it misses the questions that matter: whether earnings convert to cash, whether they will continue, and what obligations sit outside the balance sheet.
How long should financial due diligence take?
It depends on the size and complexity of the business and how quickly data is provided. What matters more than duration is starting early enough that findings can still influence price and structure, and covering trading up to signing.
Is reviewing audited financial statements enough for an investment decision?
No. Audited statements are a reliable starting point, but they cover a past period, involve management estimates, and do not address concentration, management depth or future sustainability.
What sources should be used to verify management data in India?
Typical sources are the general ledger, GST returns, the Annual Information Statement and Form 26AS, bank statements, MCA filings including registered charges, loan sanction letters, and the underlying customer and supplier contracts.
How should due diligence findings be reflected in the share purchase agreement?
Quantified issues can adjust price or the working capital target. Known but uncertain exposures are usually covered by specific indemnities, escrows or holdbacks, while matters that must be fixed before closing become conditions precedent.
Should investors rely on the seller's vendor due diligence report?
A vendor report can speed up the process, but it is commissioned by the seller. Buyers should understand its scope and limitations, obtain reliance where possible, and run their own targeted tests on the assumptions that drive value.
Conclusion
Most deal losses can be traced back to a question nobody asked. Due diligence adds value when it challenges the numbers, tests them against independent evidence, looks beyond the last audit date and turns every finding into a commercial consequence. The aim is not to find comfort. It is to find the risks while there is still time to price them, structure around them or walk away.
Planning an acquisition or investment?
H K Davra & Co. carries out financial due diligence, quality of earnings and working capital reviews for buyers, investors and lenders.
Talk to usThis article is for general information only and does not constitute professional advice or solicitation. Examples and figures in this article are illustrative. Provisions are summarised as of October 2026. Please refer to the relevant provisions and seek advice on your specific facts.