A buyer, lender or solicitor usually asks how to do financial due diligence when a transaction is already moving quickly and the available figures look reassuring. The right answer is to verify the source records, test whether reported earnings convert into cash, examine liabilities and ownership, and challenge the controls that could turn a profitable business into an expensive problem. Financial due diligence should produce evidence that changes a decision, not a longer list of documents.
Table of Contents
- What Financial Due Diligence Actually Covers
- Scoping the Engagement and Building the Information Request
- Analysing Historic and Pro-Forma Financials
- Working Capital, Cash Flow, Tax and Contingent Liabilities
- Where UK Deals Actually Lose Money
- Red Flags, Reporting and a Practical Worked Example
- Reader Questions and Next Steps
What Financial Due Diligence Actually Covers
In this illustrative scenario, a private-equity-backed acquirer is three weeks from completing the purchase of a £40 million UK services target. The finance lead discovers that statutory payroll costs are £600,000 higher than the data room suggested. The issue isn't merely an accounting variance. It affects adjusted earnings, cash requirements, working capital, tax, warranties and potentially the price.
That is the type of discovery financial due diligence is designed to prevent. It independently verifies historic financial information, stress-tests management's projections and identifies liabilities, control weaknesses and earnings-quality issues that may affect price, deal structure or completion.
A competent review normally covers:
- Quality of earnings, including recurring revenue, normalised operating costs and the bridge from reported EBITDA to adjusted EBITDA.
- Working capital and net debt, including debt-like balances, cash restrictions and the level of cash the business needs to trade normally.
- Revenue quality, including cut-off, customer concentration, contract terms, churn, pricing and collectability.
- Cost completeness, particularly payroll, pensions, contractors, bonuses and costs held outside the normal ledger.
- Cash flow sustainability, comparing reported profit with operating cash and investigating material differences.
- Tax, compliance and contingent liabilities, including HMRC correspondence, regulatory exposure and claims.
The UK accounting and transaction context
The work should be anchored to the basis on which the target prepares its accounts, including relevant FRS 102 requirements. Revenue recognition, estimates, leases, financial instruments and related-party disclosures must be assessed against that basis rather than against an informal management interpretation.
A chartered management accountant or chartered accountant usually leads the financial work, while legal advisers investigate title, contracts, litigation and enforceability. The disciplines overlap, but they answer different questions. Financial due diligence asks whether the numbers and cash economics are reliable. Legal due diligence asks whether rights, obligations and remedies are properly documented.
The commissioning audience also changes the emphasis. A trade buyer may focus on integration and sustainable margins. A lender may prioritise liquidity and covenant headroom. An insurer may need defensible loss quantification. A litigator may require a reconstruction of transactions and causation rather than a purchase-price recommendation.
The final output should include a quantified adjustments schedule, a defensible working-capital target, tax and contingencies commentary, clear red flags and an opinion on whether the information can be relied upon for the decision being made. Readers seeking a broader process map can also review this guide to understanding financial due diligence stages.
Scoping the Engagement and Building the Information Request
The first week should settle the engagement before anyone starts marking documents as reviewed. The adviser needs to know the transaction timetable, the intended decision date and the level of reliance expected. A full-scope report, a limited review and agreed procedures are different products, with different conclusions and limitations.
The preparation basis must be recorded at the outset. The target may provide audited accounts, management accounts, an IFRS reconciliation or FRS 102 accounts. Each source answers a different question, and none should be treated as interchangeable without reconciliation.
Agreeing scope and access
The scoping call should identify:
- Transaction purpose, whether acquisition, refinancing, insurance claim, shareholder dispute or investment review.
- Reporting audience, such as an investment committee, board, lender, solicitor or insurer.
- Materiality and reliance, including what would trigger escalation and what cannot be concluded from the available records.
- Related workstreams, particularly tax, legal, commercial, IT, cyber, HR and operational reviews.
- Access arrangements, including one secure data room, read-only access to raw files, a named finance contact and an executive sponsor who can unblock requests.
A secure data room works only when documents are current, indexed and version-controlled. A spreadsheet labelled “final” may not be final. The request log should record what was requested, when it was uploaded, who supplied it and whether the response was complete.
For a practical starting point, the ten-step financial due diligence checklist can help management and advisers organise requests before the review begins.
Building the request list
The list should be grouped so that missing evidence becomes visible quickly:
- Corporate and statutory: filed Companies House accounts, confirmation statements, board minutes, share register and PSC filings.
- Finance and accounting: trial balances, monthly management accounts, general ledgers, bank reconciliations, debtor and creditor ageing analyses, budgets and forecasts.
- Payroll and pensions: payroll registers, PAYE records, pension scheme schedules, contractor lists, bonus arrangements and employment-cost reconciliations.
- Tax: corporation tax computations and CT600s, VAT returns, PAYE correspondence, R&D claims, HMRC enquiries and payment records.
- Treasury: bank statements, facilities, security documents, guarantees, overdrafts, intercompany balances and director loans.
- Commercial and operational: customer and supplier contracts, pricing schedules, order books, returns, rebates and service-level commitments.
- IT and systems: finance-system access, incident logs, payment permissions, backups, cyber policies and outsourced finance arrangements.
- Legal touchpoints: litigation letters, warranties, indemnities, leases, pensions disputes and regulatory correspondence.
For a £20 million to £50 million deal, an indicative window of two to three weeks may be available before heads of terms expire. That timetable is achievable only when the data room is populated promptly and management answers questions directly.
Analysing Historic and Pro-Forma Financials
Analysis starts with reconciliation, not interpretation. Management accounts should be tied to filed statutory accounts, the trial balance should agree to the ledger and every material difference should be explained before the reviewer accepts the management narrative.
The UK Government's published Companies House accounts material identifies management accounts, statutory filings, bank statements, VAT and PAYE records, aged receivables and payables, unusual journals, complex transactions and management estimates as important areas when considering financial information integrity. That makes a source-of-truth reconciliation the first substantive control, not an administrative exercise. The Companies House annual report and accounts provides the relevant public context.
Revenue, costs and estimates
Revenue testing under FRS 102 Section 23 should address period-end cut-off, multi-year contracts, variable consideration and whether the business acts as principal or agent. Subscription businesses may recognise revenue over service periods. Construction businesses may rely on contract progress and estimated costs to complete. Retail businesses face returns, rebates, discounts and timing issues around dispatch and acceptance.
Cost completeness needs equal attention. Payroll should be reconciled to the ledger, PAYE and pension records. Supplier confirmations and bank statements can expose contractors, off-payroll arrangements, unpaid bonuses or costs routed through related parties.
Management estimates deserve a separate schedule. Bad-debt provisions, stock obsolescence, warranty claims, deferred consideration and share-based payments can materially alter sustainable earnings without appearing as obvious errors.
Journals requiring scrutiny include:
- Top-side adjustments, posted outside the normal close process.
- Period-end reversals, particularly where the reversal isn't supported by a subsequent invoice or delivery.
- Round-number entries, which may reflect unsupported estimates.
- Reclassifications, especially transfers between operating and non-operating lines.
- Late entries, where the explanation depends on a forecast rather than an underlying document.
Practical rule: Every adjustment should have a source document, a rationale, an accounting treatment and a clear effect on valuation or cash.
Pro-forma claims
A management EBITDA bridge should distinguish historical fact from future expectation. A recent hire may be a credible run-rate adjustment if the cost and start date are evidenced. An uncontracted synergy is an assumption, not an adjustment to historic earnings.
Sensitivity testing should use customer concentration, churn, pricing data and actual collection patterns. It should also identify what management hasn't adjusted for, such as cyber-incident remediation, new compliance expenditure or costs needed to replace an outsourced process.
The following table shows the types of adjustments that commonly require testing:
| Adjustment Type | Example | Diligence Test |
|---|---|---|
| Non-recurring cost | A genuine, completed restructuring | Verify invoices, approvals and whether similar costs recur |
| Owner-related item | Personal or non-commercial expenditure | Inspect supporting records and establish an arm's-length replacement cost |
| Run-rate change | A confirmed pricing or staffing change | Check contracts, payroll and the date the change became effective |
| Capitalised expenditure | Software or development costs | Test the accounting policy, timesheets, asset register and future maintenance burden |
| Revenue normalisation | A one-off project or unusual rebate | Trace the contract, invoice, acceptance evidence and repeatability |
| Synergy assumption | A proposed procurement saving | Separate it from historic EBITDA and require an implementation plan |
For readers assessing the value of forecast cash flows as well as historic results, discounted cash flow for valuations offers related context. The important distinction is that a valuation model can incorporate assumptions, while a diligence report must clearly label them.
Working Capital, Cash Flow, Tax and Contingent Liabilities
Working capital should be reconstructed, not accepted from the closing balance sheet. A reviewer should calculate a 12-month trailing average from month-end trial balances, reconcile the result to the balance sheet and agree the definition before negotiations begin.
A single month can be distorted by seasonality, delayed invoicing, accelerated supplier payments or an unusual collection. The target in the purchase agreement needs to represent normal trading requirements, not a balance produced for completion.
Cash and debt-like items
Cash should be reconciled to bank statements and separated into unrestricted, restricted and operationally necessary balances. Post-period movements can reveal one-off inflows, window-dressing or cash that was never available to the business.
Debt-like items often sit outside the formal borrowing schedule. The review should consider:
- Director loans and intercompany balances, including whether they will be settled at completion.
- Unpaid dividends and accrued bonuses, particularly where the buyer will inherit the obligation.
- Lease commitments and dilapidations, where the accounting presentation may not show the full economic cost.
- Guarantees and security, including obligations given for related entities.
- Deferred or contingent consideration, which may become payable after the transaction.
Cash-flow quality is tested by comparing operating cash with EBITDA and investigating the gap. Debtor days, creditor days and stock turn should then be stress-tested against actual collections, supplier terms and inventory movement. A profitable target that repeatedly needs external funding to support ordinary trading requires a different price and financing structure from one that converts earnings into cash consistently.
Tax and contingent exposure
The evidence request should include HMRC correspondence, self-assessment filings where relevant, corporation tax computations, CT600s, R&D claims, VAT returns and open enquiry records. The reviewer should not assume that a filed return means the position is settled.
Legal and operational evidence also matters. Warranties, indemnities, litigation letters, pension scheme valuations and the contingent-liability note may identify obligations that aren't visible in EBITDA. Regulated businesses require additional attention to Consumer Duty, FCA matters or HSE issues where those risks could create remediation costs, customer redress or operational restrictions.
The working capital adjustment should be understood as a negotiated mechanism supported by evidence. It isn't a substitute for analysing why the target needs the level of working capital proposed.
Where UK Deals Actually Lose Money
Traditional financial due diligence can spend considerable effort on EBITDA while missing the payment process that allows cash to leave the business. The more contrarian conclusion is that deal losses often arise from fraud, weak controls and people risk rather than from an obvious misstatement in the income statement.
The UK Crime Survey for England and Wales estimated 4.16 million fraud offences in the year to March 2025, a 31% increase on the prior year, according to the Government's Economic Crime Plan 2 outcomes progress report. Separately, UK Finance reported £629.3 million stolen in the first half of 2025 and 2.09 million confirmed fraud cases, up 17% year on year, in its Half Year Fraud Report 2025.
The National Assessment Centre identified payment diversion fraud and investment fraud among the highest-harm fraud types in the UK in 2025. The same published material records that more than 70% of fraud against UK citizens or businesses is assessed to emanate from, or be facilitated via, overseas jurisdictions, while 63% of frauds reported to Action Fraud in the year to March 2025 were cyber-enabled.
Tests that conventional reviews miss
The fraud workstream should test:
- Payment authority: whether one person can create and release a payment, including payments above an internally meaningful threshold.
- Bank-detail changes: whether supplier changes require independent call-back verification and dual approval.
- Sales-to-cash controls: whether credit notes, refunds and customer-bank changes are segregated.
- Purchase-to-pay controls: whether duplicate vendors, dormant suppliers and related parties are reviewed.
- Digital access: MFA coverage, phishing exposure, privileged access and incident logs.
- People risk: dependency on key individuals, right-to-work evidence, whistleblowing records and unusual related-party transactions.
The PSC review belongs in this workstream. A person with significant control may be someone who holds more than 25% of shares or voting rights, can appoint or remove a majority of directors, or otherwise exercises significant influence or control. The Companies House PSC guidance sets out the specified conditions.
Companies must identify PSCs and report them to Companies House, so reviewers should compare the PSC register with shareholdings, voting rights, constitutional documents and recent changes. The official PSC requirements collection explains the reporting framework. Where integrity concerns emerge, the potential exposure should be quantified and reflected through price, warranties, indemnities, escrow or a remediation condition.
Teams refining liquidity controls may also find this practical overview of cash flow forecasting strategies useful, provided it is treated as supporting process guidance rather than a substitute for transaction-specific testing.
Red Flags, Reporting and a Practical Worked Example
Certain findings should stop the review from progressing on the assumption that the numbers are broadly sound. Escalation is appropriate where gross margins move without operational support, revenue is recorded before delivery, related-party purchases aren't at arm's-length prices, or invoices appear circular.
Other warning signs include aggressive capitalisation, large late journals, qualified audit opinions, going-concern indicators, undisclosed HMRC enquiries and weak PSC integrity. None is automatically a deal-breaker. Each requires evidence, quantification and a decision about price, structure, protection or withdrawal.
What the report should deliver
A decision-ready report normally contains:
- An executive red-flag page, written for the investment committee, board or lender.
- A quality-of-earnings analysis, with a bridge from reported to adjusted EBITDA.
- A working-capital target, including definitions and exclusions.
- A debt-like items schedule, with cash and restricted-cash commentary.
- A tax and contingent-liabilities summary, linked to open questions and source records.
- A limitations section, identifying missing documents, reliance restrictions and unresolved management explanations.
A tight review may run over two to three weeks, while a standard engagement may take four to six weeks, depending on complexity, record quality and access. The core team may include a lead chartered accountant, junior analyst, tax specialist and the counterparty CFO or finance director. Specialist legal, IT or regulatory input should be added where the evidence indicates a material issue.
Further reading on financial due diligence for acquisitions can help readers compare common red-flag categories, but the final report still needs transaction-specific evidence.
Hypothetical worked example
A hypothetical Yorkshire manufacturer reports turnover of £12 million and EBITDA of £1.8 million. The review identifies a non-recurring item, an owner-related cost, incomplete payroll costs and a recurring operational expense incorrectly presented as exceptional. Adjusted EBITDA falls to £1.1 million.
The working-capital analysis supports a target of £1.5 million. Separately, the PSC review and payment-control testing identify a potential £400,000 exposure connected with ownership-integrity concerns and APP fraud vulnerability. The amount isn't presented as a proven loss. It is an exposure requiring investigation, protection and a negotiated response.
| Line Item | Amount (£000s) | Notes |
|---|---|---|
| Reported EBITDA | 1,800 | Management presentation |
| Less: unsupported one-off adjustment | (250) | Evidence doesn't support full add-back |
| Less: owner-related normalisation | (150) | Replacement cost required |
| Less: incomplete payroll and contractor cost | (200) | Reconciled to payroll and supplier records |
| Less: recurring operating expenditure | (100) | Not genuinely exceptional |
| Adjusted EBITDA | 1,100 | Diligence conclusion before buyer synergies |
| Working-capital target | 1,500 | Hypothetical target based on normal trading |
| PSC and APP-fraud exposure | 400 | Risk adjustment requiring investigation and protection |
The correct conclusion isn't “reduce the price”. The buyer may also seek a specific indemnity, enhanced completion conditions, payment-control remediation and evidence that the relevant exposure has been resolved or ring-fenced.
Reader Questions and Next Steps
Should the provider be independent?
Yes. The adviser should be free to challenge management, the seller, the buyer and other professional advisers. Independence doesn't mean the provider has no commercial interest in being appointed. It means the analysis is evidence-led, limitations are disclosed and conclusions aren't softened to preserve the transaction.
When should confidentiality be addressed?
Before sensitive records are uploaded. An NDA should be agreed with the correct parties, and the data room should restrict access according to role. The engagement letter should explain permitted use, reporting recipients, confidentiality obligations, document retention and whether the work may be disclosed to lenders, insurers, counsel or a court.
What drives the cost?
The main factors are scope, transaction complexity, record quality, number of entities, accounting basis, regulatory exposure, timetable and the amount of specialist work required. A clean data room and responsive finance contact reduce duplicated effort. Missing records, changing scope and late management explanations increase it.
Does a smaller SME need a large advisory firm?
Not necessarily. A smaller business may need a narrower review, but it still needs someone who understands transaction accounting, cash conversion, tax evidence, ownership and fraud controls. The right provider should match the depth of work to the decision and explain what a limited review cannot establish.
How long will an SME review take?
An SME trading below the audit threshold may complete a focused review within a shorter timetable than a complex group, but the answer depends on records and access. Companies House deadlines also matter. The Government confirmed that temporary automatic filing extensions ended on 5 April 2021, after which further automatic extensions did not apply to confirmation statements, accounts filings or event-driven filings, as explained in its filing-extension announcement. Late filings should therefore be investigated rather than dismissed as pandemic-related administration.
What should happen next?
The sensible next step is a short scoping discussion. The adviser should clarify the decision being made, the records available, the timetable, the intended users of the report and the issues most likely to affect value or liability.
Lighthouse Consultants provides independent due diligence and financial analysis for acquisitions, investment reviews, lenders, solicitors, insurers and businesses facing unexplained financial issues. To discuss the records, scope and decision timetable with a practitioner, visit Lighthouse Consultants.
