If you are selling a business, or the shares in the company that runs it, the buyer will almost always ask for warranties, and wherever there are warranties there is usually a disclosure letter. The letter is the seller's instrument in that part of the deal. It records, before completion, the exceptions to the promises in the sale agreement, so the buyer cannot later claim breach of warranty about something it was already told.
The disclosure letter does not cure problems in a business, and it is not a marketing document. It performs one practical job: it draws the boundary around what the seller is actually promising. Where that boundary sits decides, after settlement, who pays when something unexpected surfaces in the accounts, the contracts or the tax position. This guide walks through how the mechanism works, who produces it, what triggers it, how the fair disclosure standard operates in practice and where the disputes usually begin.
The cast: seller, buyer and their lawyers
Three sets of people make a disclosure letter work, and their interests pull in opposite directions.
- Seller: knows the business best, and usually prepares the first draft. The seller wants each warranty qualified as far as the buyer will accept, so that risk stays with the buyer after completion.
- Buyer: reviews the letter warranty by warranty and tests whether each disclosure is specific enough to understand. The buyer wants the warranties left intact, so that problems found later stay the seller's problem.
- Both sides' lawyers: negotiate the wording of the letter and of the disclosure standard in the agreement. In most deals they end up working through the letter line by line against the warranty schedule.
That tension is not a flaw, it is the design. A disclosure letter is the negotiated settlement of a contest between a seller narrowing its promises and a buyer widening them. It only works because the sale agreement itself says what counts as effective disclosure, and both sides have agreed to be bound by it.
The trigger: warranties in the sale agreement
The disclosure letter only exists because of warranties. In a share sale or a business sale the seller makes promises about the state of the business: that the accounts are true and fair, that it owns the assets it claims to own, that it has complied with relevant laws, that there is no undisclosed litigation and that key contracts are valid and enforceable. If any of those promises turns out to be wrong, the buyer can claim damages for breach of warranty under the agreement.
The warranties sit in a schedule to the sale agreement, and the agreement usually makes them subject to what the disclosure letter reveals. A clause of that kind appeared in the agreement considered in Mediservices Clinics Pty Ltd v Health 24 Pty Ltd [1999] NSWCA 198, a dispute over the sale of medical centre businesses. The warranty was expressed to be true "save as disclosed" in a nominated part of the schedule. The buyer sued over a sublease with an unusually high rent that was not mentioned in the disclosure schedule, arguing that it was an "unusual item" the accounts warranty should have caught. The New South Wales Court of Appeal held that "unusual" was to be construed subjectively, according to what the parties themselves regarded as unusual, and the claim failed.
The lesson cuts both ways. The protective reach of a warranty, and therefore the value of a disclosure, depends entirely on the precise wording of the clause and of the disclosure schedule. A matter that looks obvious to one side can fall outside the warranty, or inside it, depending on how the words were chosen.
What a disclosure letter does
When a disclosure is made properly, it qualifies the corresponding warranty. Take a warranty that the company has no current litigation. If a supplier has an unresolved dispute with the company, the disclosure letter flags the dispute, names the parties, states the amount in issue and points to the documents that evidence it. The warranty is then read as if it said "there is no litigation other than the supplier dispute disclosed in the letter".
General and specific disclosures
Two kinds of disclosure do most of the work. General disclosures cover matters that are already visible to the buyer: information on the public record such as ASIC records, documents the buyer received during due diligence, and matters reasonably apparent from those documents. They are signposts rather than explanations. Specific disclosures deal with concrete exceptions to particular warranties: a dispute, a breach, a missing consent, a liability that the accounts do not fully reflect. Each one should state the issue plainly and link to the supporting document, so the buyer can see the nature, scale and likely impact of the problem.
The fair disclosure standard
Most sale agreements set a standard that the disclosures must meet, usually expressed as a requirement that disclosure be "fair". What that means in practice is set by the wording of your agreement. The common commercial sense of it is that a disclosure must be specific enough for a reasonable buyer to understand what is being disclosed and how significant it is. Vague statements of the kind "there may be disputes from time to time" are generally not treated as effective disclosure, because they tell the buyer nothing it could act on.
Because the standard is contractual, it pays to read it before drafting. If the agreement requires disclosures to refer to particular documents in the data room, the letter needs to match that requirement. Whether a disclosure actually qualified a warranty is, in the end, a question of construction of the agreement, which is why disputes about disclosure letters are fought over documents and wording rather than over intentions.
When the process runs
A disclosure letter is not a document the seller produces in isolation. It runs alongside the due diligence process and the negotiation of the sale agreement itself, and it appears in share sales, in business and asset sales, and in investment rounds where founders give warranties to incoming investors. The mechanism is the same in each, though the warranty schedule and the risk profile differ.
The usual sequence in a small to medium business sale looks like this. The buyer signs a confidentiality agreement and then runs due diligence over the business, reviewing the accounts, contracts, employees, property, intellectual property and compliance records. The seller prepares the first draft of the disclosure letter, working through the warranty schedule and identifying every exception. The buyer's lawyers review the letter, test each disclosure against the warranties, and push back where a disclosure is too vague or too broad. The final letter is signed and dated, usually at the same time as the sale agreement.
The timing matters. In most transactions the letter is settled before signing, so the buyer knows the qualified scope of the warranties before it commits. In some deals disclosures are also permitted between signing and completion, usually through a supplemental letter. What the buyer can do about a late disclosure, including whether it can terminate or renegotiate, depends on the terms of the agreement.
The machinery of a letter that holds up
A disclosure letter is only as good as its internal organisation and its alignment with the deal documents. The steps that make the difference are mostly mechanical.
- Align the letter with the warranty schedule, heading by heading, so every disclosure can be matched to the warranty it qualifies.
- Keep a data room that is organised and labelled, with each disclosure pointing to a specific document and folder.
- Use an index and consistent document names, so there is no argument later about whether a document was actually provided.
- Calibrate disclosures to the agreement's defined terms. If the agreement only requires disclosure of material matters, or defines "knowledge" to include particular officers, make sure those people were consulted and those thresholds applied.
- Reconcile the letter with due diligence. If the buyer asked specific questions, make sure the answers are captured and linked to the underlying documents.
- Flag matters that need action before completion, such as a landlord's consent to an assignment or the novation of a customer contract, and tie them to the completion deliverables.
For a seller, the same discipline applies in reverse when something changes after signing. If a material issue arises before completion, a supplemental disclosure may be needed, and the agreement usually says what the buyer may do in response. Checking that before the event is cheaper than arguing about it after.
Where it bites: warranty claims and the fallbacks
The real test of a disclosure letter comes after completion, when something the buyer did not expect shows up. Three Australian authorities illustrate what happens then.
First, the buyer's remedy for a breach of warranty is damages under the agreement, and for a buyer who was induced to buy by a misrepresentation, the classic measure is the difference between the price paid and the true value of what was bought, per Potts v Miller (1940) 64 CLR 282. The High Court's formulation still governs how courts approach damages questions in share sale disputes.
Second, the buyer may try to step outside the contract entirely and sue for misleading or deceptive conduct. Section 18 of the Australian Consumer Law, which is Schedule 2 of the Competition and Consumer Act 2010 (Cth), prohibits conduct in trade or commerce that is misleading or deceptive or likely to mislead or deceive. Silence can be misleading in that sense where the circumstances create a reasonable expectation that a matter would be disclosed.
Third, courts are alive to the commercial reality of who took the risk. In Wormald v Maradaca [2020] NSWCA 289 the sellers of shares had agreed to put $200,000 into escrow to meet any warranty claim, with release if no claim was made within 90 days. When the buyer later complained that the sellers had not disclosed a rival offer for the company, the New South Wales Court of Appeal rejected the misleading conduct claim. The buyer had been offered the chance to do further due diligence and declined, and as an experienced commercial participant it had taken a calculated risk. The refusal to allow due diligence, the Court held, negatived any reasonable expectation of further disclosure.
The practical translation is blunt. A buyer that skips due diligence and relies on warranties alone has a thinner safety net than it may think, and a seller that treats the disclosure letter as a formality leaves the warranty schedule to do its worst after settlement.
When a lawyer earns their fee
The value of legal input concentrates at two points. Before signing, a lawyer cross-checks the disclosure letter against the warranty schedule and against the agreement's disclosure standard, knowledge definitions and materiality thresholds, and negotiates the wording of the standard itself. After signing, a lawyer advises on supplemental disclosures and on what the agreement permits the buyer to do in response.
For a seller, the cost of getting the letter wrong is a warranty claim that the disclosure was meant to prevent. For a buyer, the cost of accepting vague disclosures is a warranty that is effectively worthless. In both cases the exposure is usually far larger than the legal fee, which is why both sides are better served by a line-by-line review before the letter is signed.
Signing fixes the letter
The moment that decides whether a disclosure letter does its job is the same for both sides: signing. From that point the letter is fixed, and the fair disclosure standard in the agreement becomes the yardstick by which every later dispute is measured. The seller who wants the letter to protect it should have each disclosure read against the warranty it qualifies, and the buyer who wants the warranties to mean something should test each one against what a reasonable purchaser would need to know. That calibration happens before the signatures go on, not after, and it is precisely the kind of review a commercial lawyer completes in a focused session. A short consultation at the drafting stage costs a fraction of the argument it can prevent.