Five recurring patterns flag a target company as higher-risk during pre-investment due diligence: revenue concentration that does not match the management narrative, working-capital trends inconsistent with reported growth, abnormal year-end timing of cash receipts, related-party arrangements not at arm's length, and accounting policy changes adopted in the run-up to sale. None of them automatically disqualifies an investment. Each one tells a forensic reviewer where to look harder.
In this article
- Why do red flags matter at pre-investment stage?
- Red flag 1: revenue concentration the narrative does not acknowledge
- Red flag 2: working capital that contradicts the growth story
- Red flag 3: abnormal year-end cash timing
- Red flag 4: related-party arrangements not at arm's length
- Red flag 5: accounting policy changes timed to the sale
Why do red flags matter at pre-investment stage?
Red flags do not necessarily mean the target is mispriced or the management is dishonest. They mean the investor needs to ask sharper questions before committing capital. Investors who treat red flags as binary (deal/no deal) miss good investments. Investors who ignore them or accept first answers tend to discover the issues post-completion when the cost is much higher.
The discipline is to identify the flags, ask the targeted question, and assess the answer. Where the answer is satisfactory and verifiable, the flag closes. Where the answer is evasive, contradictory, or supported only by the management narrative, the flag remains open and the investment is repriced or restructured to reflect that.
Red flag 1: revenue concentration the narrative does not acknowledge
Most management narratives describe a diversified customer base. Most actual customer ledgers show that 50% to 80% of profit comes from the top three to five customers. The gap between narrative and reality is itself the flag. The forensic test is straightforward: pull the customer ledger, calculate concentration on revenue and on margin, and benchmark against the management description. Where the gap is material, the buyer asks why.
The best answer is that diversification is in progress and verifiable through the pipeline data. The worst is that the concentration was never volunteered. According to the 2024 EY Global PE Trends Report, around 26% of post-completion losses on lower-mid-market PE investments traced back to undisclosed customer concentration combined with subsequent customer attrition.
Red flag 2: working capital that contradicts the growth story
A growing business consumes working capital. If reported revenue is up 25% but receivables and inventory are flat, something is unusual. The most likely benign explanation is that the growth has not yet flowed through to the balance sheet because the period was unrepresentatively front-loaded. The most likely concerning explanation is that revenue has been pulled forward through aggressive recognition or that receivables have been factored without disclosure.
The forensic test is to align the trailing P&L growth with the trailing balance-sheet movement and to check the cash flow statement against both. Where the three do not reconcile, there is something the management has not yet explained. The honest answer is recoverable; the absence of an answer is the flag.
Red flag 3: abnormal year-end cash timing
Year-end cash positions are often higher than mid-year averages because customers are encouraged to pay before period close and supplier payments are deferred. A modest pattern is normal. A material pattern, cash on year-end day at 200% of the trailing 90-day average, usually indicates a deliberate optimisation of the reported balance sheet. This matters because the working capital bridge in the deal is anchored to that date.
The forensic test is to plot daily cash for the 60 days either side of year-end and look at the pattern. A clean business shows a smooth line with normal variation. A managed year-end shows a spike on the closing day and a sharp drop in the following week. The latter is the flag. The fix in the deal is to use the trailing average rather than the spot figure for the working capital bridge.
Red flag 4: related-party arrangements not at arm's length
Owner-managed businesses are full of related-party arrangements: properties rented from the owner's pension, services provided by a connected company, salary or dividends to family members. Many are entirely legitimate. Some are not at arm's length and are quietly subsidising the reported numbers. After acquisition, the new owner cannot continue these arrangements on the same terms, and the cost flows into the post-completion P&L.
The forensic test is to identify every related-party arrangement, benchmark each one to market terms, and quantify the difference. Where the difference is material, the deal model is adjusted to reflect the post-completion cost. The seller may resist this adjustment. The investor's leverage to make it stick depends on having identified the issue early and built it into the bid logic.
Red flag 5: accounting policy changes timed to the sale
Material changes in accounting policy in the year or two before sale are worth a careful look. Capitalising development costs that were previously expensed. Lengthening the depreciation life of plant. Changing inventory valuation methodology. Each can be entirely defensible. Each also has the effect of improving reported EBITDA at exactly the moment the seller most benefits.
The forensic test is to restate the trailing P&L on a consistent policy basis and compare with the reported figures. Where the gap is material, it indicates that the reported trend is partly the result of policy change rather than underlying performance. The defensible policy may still be the right one, but the deal multiple should be applied to the consistent number.
Written by Bharat Varsani FCCA. Director of Key Ledgers Global. CPR Part 35 Forensic Expert Witness with 20+ years across forensic accounting, audit and CFO advisory. Currently operating at CFO level within a 15-entity care and property group with £205m of assets under management.
Sources: EY Global PE Trends Report 2024 for the cited 26% post-completion attrition figure; FRC published guidance on accounting policy disclosures and consistency.
Frequently asked questions
Are all red flags grounds to walk away from a deal?
No. Red flags identify where to look harder. Most close cleanly with satisfactory answers. The discipline is to ask the targeted question and assess the response. Where answers are evasive or unverifiable, the flag remains open and is reflected in pricing or structure.
What is the difference between forensic and standard financial due diligence?
Standard FDD focuses on the accuracy and completeness of reported financials. Forensic review additionally tests for patterns that suggest deliberate optimisation, undisclosed concentration risk, or off-balance-sheet exposure. Forensic work usually adds 15% to 25% to FDD cost and is calibrated to deal complexity.
How long does forensic pre-investment review take on a £25m deal?
Three to four weeks of focused work, in parallel with formal FDD. The output is a short report identifying the open issues, the recommended deal adjustments, and the post-completion monitoring priorities.