Balances or documentary verification: which, and when
One asks the debtor whether it owes the money. The other asks the paperwork whether the debt was earned. They answer different questions, and choosing the wrong one gives you a clean result that proves nothing.
On Business Audits · 23 September 2026 · 5 min read
Verification is the part of due diligence that tests individual debts rather than the client’s systems. Two kinds are common, and they are often treated as interchangeable. They are not. Each answers one question well and another question badly, so the choice depends on what you are worried about.
Balances verification: does the debtor agree it owes the money?
A balances verification goes to the debtor. You, or an auditor acting for you, ask the debtor to confirm what it owes your client at a given date, either as a total or invoice by invoice. The answer comes from outside the client’s business, which is its great strength. A client can produce an invoice for anything. It cannot easily make a large retailer’s accounts payable team agree to a balance it does not recognise.
What a balances verification tells you:
- The debt exists in the debtor’s own records.
- The amount is agreed, or there is a difference to explain: a credit note the debtor has taken, a dispute, an invoice it has never received.
- Timing: whether the debtor expects to pay on the terms the ledger implies.
What it does not tell you is whether the debt was earned properly. A debtor may confirm an invoice for goods it has not yet received, simply because the invoice has reached its ledger. That is how pre-invoicing survives a balances check.
Documentary verification: was the debt earned?
A documentary verification goes to the paperwork behind each invoice: the customer’s order, the delivery note or proof of delivery, the timesheet for services, and sometimes the contract. The test is whether the goods were delivered or the work was done before the invoice was raised, in the quantities invoiced, to the customer named.
What a documentary verification tells you:
- The invoice follows the work, not the other way round. A delivery note dated after the invoice is the classic sign of pre-invoicing.
- Quantities agree across the order, the delivery and the invoice.
- The paperwork is consistent: the same customer, the same address, a signature where one is expected.
What it does not tell you is whether the debtor accepts the debt today. Goods can be delivered and still be disputed, returned or set off against something your client owes.
Choosing between them
Start with the question you need answered.
| What worries you | The better test | Why |
|---|---|---|
| The debt may not exist | Balances | Only the debtor can confirm it from outside |
| Invoices raised before delivery | Documentary | The dates on the paperwork show it |
| Credit notes being held back | Balances | The debtor will quote the lower figure |
| A new debtor with no history | Both | Existence and substance are both unproven |
| Disputes on the ledger | Balances | The debtor will say what it disputes |
| Quantities inflated | Documentary | Orders and deliveries show the true quantity |
Where the facility is confidential, balances verification needs care, because the debtor does not know about your interest. It is usually done in the client’s name, or in a way the facility allows. Documentary verification raises no such issue. The paperwork is the client’s, and asking for it is ordinary audit practice.
How many to test
Neither test is a census. You choose a sample, and the sample decides what the result is worth. Two rules help:
- Weight the sample towards value. A handful of the largest balances often covers a large share of the ledger. Add a random selection of smaller items so that a pattern hidden among them has a chance to appear.
- Include what is new or unusual. New debtors, invoices raised on the last days of a month, round-sum invoices and debtors in a different trade from the rest all deserve a place.
A sample of twenty or thirty invoices, chosen this way, will tell you more than a hundred chosen at random. Record why each one was chosen, so that the next audit can test the same things.
Reading the result
A clean result needs reading as carefully as a bad one. If every balance agreed, ask whether the debtors you wrote to were the ones you were most worried about. If every document agreed, ask whether any invoice was raised on the last day of the month, and when its delivery note was dated.
Differences need explaining one at a time. A debtor that confirms £18,000 against a ledger balance of £21,000 may be holding a £3,000 credit note your client has not posted, may have paid an invoice the client has not allocated, or may dispute a delivery. Each has a different consequence for what you lend against. Ask the client for the explanation and the evidence, and record both.
Using both
The strongest position comes from running the two tests on the same invoices. If the debtor confirms an invoice and the delivery note shows the goods arrived before it was raised, you have a debt that exists and was earned. If the debtor confirms an invoice whose goods left a week after it was raised, the confirmation has told you something the debtor did not intend: that its payables team books invoices without matching them to deliveries, and that your client knows it.
That is why we usually recommend documentary verification as part of every audit, with balances verification added where the facility and the question call for it.