Fifteen Things That Quietly Knock Value Off Your Business in Due Diligence

Deals do not usually collapse. They erode.

I have sat on both sides of enough transactions to know that the dramatic version, where something terrible is discovered and everybody walks away, is rare. What actually happens is quieter and more corrosive. A dozen small things surface over eight weeks. None of them is fatal. Together they change the buyer's view of how well this business is understood by the people who run it, and once that view shifts, the price follows.

The buyer will not tell you this is happening. They will tell you the market has moved, or their investment committee has questions, or they would like to restructure the consideration. What they mean is that the business turned out to be harder to see through than they were promised.

Here are the fifteen items that do most of that eroding, roughly in the order they cost money. Each one has a lead time attached, because that is the number that should decide what you work on first.

01Customer concentration

The mechanism. If one customer is 35% of your revenue, the buyer is not acquiring your business, they are acquiring a relationship with that customer plus some overheads. They will price the risk that the relationship ends, and they will price it harshly because they have no way to assess it from outside.

What it costs. More than anything else on this list. It shows up as a lower multiple, a larger deferred element, or a specific retention condition tied to that account.

Lead time: two to three years. You cannot dilute concentration quickly. It requires winning revenue elsewhere at a rate faster than the big account grows, which is a sales problem measured in years.

02Owner dependence

The mechanism. Every hour the business needs you personally is an hour the buyer has to replace or retain. If the relationships, the pricing decisions, the technical judgement and the final word all sit with one person, the buyer is purchasing a job they will need to fill.

What it costs. It converts cash at completion into an earn-out, which is a transfer of risk to the person with the least control after the deal.

Lead time: eighteen months to three years. Handing over tasks takes weeks. Handing over judgement, and having customers accept it, takes considerably longer.

03Management accounts that do not reconcile to the statutory accounts

The mechanism. The buyer builds their model on your management accounts, then checks them against the filed accounts. If the two disagree and nobody can explain the bridge in an afternoon, every number in the model becomes suspect.

What it costs. It rarely reduces the headline price directly. It extends the process, increases the buyer's advisory fees, and produces a much longer warranty schedule.

Lead time: three to six months to fix properly, then two clean years for the fix to be worth anything.

A buyer does not reduce the price because they found a problem. They reduce it because finding one problem tells them the population of problems is larger than zero.

04Add-backs that cannot be defended

The mechanism. Every owner-managed business has costs that would not exist under new ownership. That is legitimate. What is not legitimate is a list of adjustments assembled shortly before the process that adds 20% to EBITDA and includes items nobody can evidence.

What it costs. Directly and arithmetically. If the multiple is six and you lose £200k of add-backs, that is £1.2m.

Lead time: two years. Take the personal costs out of the business and let two clean sets of accounts pass.

05Intellectual property the company does not actually own

The mechanism. Work created by contractors belongs to the contractor unless assigned in writing. A remarkable number of businesses have core software, brand assets or designs built by somebody who was never on payroll and never signed anything.

What it costs. It can stop a deal outright, particularly with a trade buyer whose interest is the technology. At best it produces an indemnity and a retention.

Lead time: three to twelve months, because it means going back to people, some of whom you have lost touch with, and asking them to sign something. Their willingness varies with how the relationship ended.

06Employment status of long-term contractors

The mechanism. People who work for you full time, use your systems, and have done so for years are employees in substance whatever the invoice says. HMRC takes an interest in this and so does any buyer, because the liability transfers.

What it costs. A quantified provision, usually with interest and penalties modelled at the pessimistic end, taken straight off the price.

Lead time: six to eighteen months to restructure, plus however long the historic exposure period runs.

07Contracts that are not signed, or not findable

The mechanism. Half of an owner-managed company's customer relationships often run on a purchase order and goodwill. That is fine commercially and unhelpful in a transaction, because revenue without a contract is revenue the buyer cannot rely on.

What it costs. It moves revenue from the recurring column to the at-risk column, which is exactly the reclassification you do not want.

Lead time: six to twelve months. The work is easy. Getting customers to sign is the slow part.

08Change of control clauses nobody has read

The mechanism. A clause allowing a customer to terminate on a change of ownership hands that customer a veto over your deal. Buyers find these. They then want to know whether the customer will consent, which means telling the customer you are selling, which is a conversation you may not want to have at that point.

What it costs. Consent conditions, timing risk, and occasionally a genuinely lost customer.

Lead time: two weeks to find them, one to three years to renegotiate them. Finding them early is what gives you the option.

09Revenue that looks recurring and is not

The mechanism. Businesses habitually describe repeat revenue as recurring. They are different things. Recurring revenue is contracted with a term. Repeat revenue is a customer who has happened to come back. Buyers pay very different multiples for each.

What it costs. A reclassification of a chunk of your revenue base, which is a direct multiple effect.

Lead time: eighteen months to three years to convert repeat into contracted, and the conversion is a commercial negotiation with every customer.

10Gross margin that nobody can explain at product level

The mechanism. Aggregate margin is an average of things that are moving in different directions. When a buyer asks which parts of the business are actually profitable and the answer takes three weeks to produce, the buyer assumes the answer is unflattering.

What it costs. It undermines the growth story, because you cannot credibly plan to grow the profitable part if you cannot identify it.

Lead time: three to nine months, and it is one of the most useful things on this list to fix regardless of any sale.

11Key person risk with no named mitigation

The mechanism. Beyond the founder, most businesses have one or two people who hold something irreplaceable: a technical capability, a customer relationship, an operational memory. Buyers identify these people quickly and then ask what happens if they leave.

What it costs. Retention packages funded out of your consideration, and sometimes a specific holdback.

Lead time: twelve to twenty-four months to document, cross-train, and put proper incentives in place.

12A pipeline that cannot be evidenced

The mechanism. The forecast is the basis of the valuation. If the pipeline lives in the sales director's head, or in a spreadsheet whose historic accuracy nobody has tested, the forecast is an assertion.

What it costs. The buyer replaces your forecast with theirs, and theirs is more conservative.

Lead time: twelve months minimum, because the value is in the track record of the pipeline, not the existence of the system.

13Data protection with no lawful basis written down

The mechanism. Most businesses process personal data lawfully and cannot demonstrate it. Buyers, particularly those with institutional backing, now treat this as a standard workstream rather than an afterthought.

What it costs. Usually warranties and a remediation plan rather than price, but it lengthens the process and adds cost on both sides.

Lead time: three to six months.

14Historic tax positions left open

The mechanism. Aggressive historic positions, unresolved enquiries, or arrangements that were fine at the time and would not be entered into now. These do not disappear on a share sale, they transfer.

What it costs. A provision, an indemnity, or an insurance premium, all of which come out of your proceeds.

Lead time: variable, which is precisely why it needs looking at early rather than discovered in week six.

15A founder who has not decided what they want

The mechanism. It is not a diligence item on any checklist, and it derails more processes than most things that are. A founder who has not settled the question of whether they actually want to sell, what they will do afterwards, and what the people around them think, will find reasons to hesitate at the point where hesitation is most expensive.

What it costs. Sometimes the deal. Always goodwill, and occasionally a relationship with an adviser or a buyer you would rather have kept.

Lead time: as long as it takes, and it is free to start today.

What to actually do with this list

Sort it by lead time rather than by how satisfying each item is to fix.

Founders reliably start with contracts and folders, because that work is visible and finite and produces the pleasant feeling of a job completed. Meanwhile the three items that genuinely move the price, concentration, owner dependence and the quality of the earnings, all take years, and they get started last.

Two years out, work on items 1, 2, 4 and 9. Everything else can be done in the twelve months before you go to market. If you have less than a year, do 1 and 2 anyway, because partial progress on those is worth more than complete progress on the rest.

And be honest in disclosure about whatever is left. Buyers price known problems reasonably. They price discovered ones as evidence of character.