Mistake in the purchase of a home: the duty to disclose and correction of loss
The buyers paid €675,000 for a home next to a permitted mega-barn
In December 2016 the claimants bought a home for €675,000. Opposite the home was an agricultural business whose owner had previously obtained irrevocable permits for the construction of a large pig shed. The sellers knew this. Between 2011 and 2013 they had themselves objected to the granting of those permits. They disclosed nothing to the buyers.
To finance the purchase, the claimants had a valuation carried out beforehand. It valued the home at €670,000 as at the reference date of 30 December 2016 — without knowledge of the permits. After completion, the claimants had a second valuation prepared, with a reference date of 20 December 2016 and on the assumption that the environmental permit granted for the mega-barn was known. The result: €485,000. The difference between the actual purchase price and that valuation is €190,000, precisely the amount the claimants claimed from the sellers.
Between the purchase and the judgment a new development occurred: in 2022 the neighbour sold his plot to a development company. In that contract the neighbour undertook to cease his business at the site and to have all permits withdrawn or transferred to the buyer. No mega-barn would therefore be built on the plot.
Court of Appeal: mega-barn blocked, loss nil — the Supreme Court undoes this
The Court of Appeal of 's-Hertogenbosch established the mistake (ECLI:NL:GHSHE:2024:432). The sellers had breached their duty to disclose (Section 6:228 DCC): they knew of the permits, had actively campaigned against them and should reasonably have understood that this knowledge would be relevant to the buyers' purchase decision. Up to this point the reasoning held.
The Court of Appeal then took the correct starting point: the buyers must be placed in the position they would have been in had they not been mistaken. Had they known of the permits, they would have bought the home, but at a lower price. The loss had to be calculated on the basis of that starting point. But the Court of Appeal then drew an incompatible conclusion: because the mega-barn ultimately did not materialise and the home had meanwhile risen in value, the buyers no longer suffered any loss. The claim was dismissed and the damages under Section 6:162 DCC were assessed at nil.
Advocate General De Bock advised setting the judgment aside (ECLI:NL:PHR:2025:304). The Supreme Court followed that advisory opinion.
The problem with the Court of Appeal's reasoning is an internal contradiction. If, with knowledge, the buyers had bought the home at a lower price, they would also have benefited in full from the later increase in value — caused by the removal of the threat. Precisely because they would have had a lower price as their starting point, they would have built up more equity. It therefore followed necessarily from the Court of Appeal's own starting point that there was indeed loss within the meaning of Section 6:230(2) DCC.
The same applied to the assessment of damages on the basis of tort. The settled standard is that the injured party must, as far as possible, be placed in the position that would have existed had the loss-causing event not occurred — the comparison between reality and the hypothetical scenario, see Section 6:97 DCC and Supreme Court 26 March 2010 (ECLI:NL:HR:2010:BL0539). Here too the Court of Appeal abandoned its own premise: in the hypothetical situation in which the sellers had disclosed what they knew, the buyers would have bought at a lower price, after which the later increase in value would have accrued to them. It follows that they paid too much at the time, and that is not undone by the mega-barn never being built (para. 3.3.3).
Both extremes did fail. The buyers argued that facts with no causal connection to the contract may play no role under Section 6:230(2) DCC, and that only circumstances existing before or at the time of contracting may be taken into account. In their conditional cross-appeal the sellers argued the mirror image: that the loss follows solely from the comparison between rescission and upholding the contract, so that the hypothetical situation without the mistake stays out of the picture. Each of those complaints rests on a view of the law that is incorrect in its generality and therefore cannot lead to cassation (para. 3.1.4). Later developments may be weighed in assessing the loss; what cannot be done is to let them operate in a way that undermines the court's own premise. Ground B.6 failed under Section 81 of the Judiciary Organisation Act.
The Supreme Court set aside the judgment and referred the case to the Court of Appeal of Arnhem-Leeuwarden for further consideration and decision.
What does this mean for buyers and sellers of real estate?
This judgment makes clear that the loss in cases of mistake and breach of the duty to disclose arises at the moment of purchase and does not disappear because the feared risk never materialises. Later developments may be taken into account, but a court which starts from the premise that the buyer would have paid a lower price had the facts been disclosed cannot then let that same development wipe out the loss. Sellers who conceal a relevant circumstance — permitted construction, a concrete planning threat, known defects — cannot later benefit from the fact that the danger never materialised. The excessive price has been paid; the loss arose at that moment.
For buyers, this judgment offers support: even where the feared situation later fell away, the claim survives. It is essential, however, that a retroactive valuation is available that substantiates the hypothetical market value at the time of purchase — with knowledge of the concealed circumstance. Compare also the judgment on asbestos after buying a home, in which the boundary between the duty to disclose and the duty to investigate was central.
Frequently asked questions
What does the seller's duty to disclose entail when a home is purchased?
Under Section 6:228(1)(b) DCC, the seller has a duty to disclose circumstances that the seller knows or ought to know and that may be relevant to the buyer's purchase decision. That duty weighs more heavily the more actively the seller is aware of the circumstance concerned — as was the case here: the sellers had themselves objected to the mega-barn permits for years.
Can the court adjust the purchase price in a case of mistake instead of rescinding the contract?
Yes. Section 6:230(2) DCC gives the court the power to modify the effects of the contract in order to remove the loss. In practice this usually leads to a price adjustment in favour of the mistaken party. The court has a wide margin of appreciation here. The Supreme Court rejected both the view that only the comparison between rescission and upholding the contract counts and the view that only circumstances existing at the time of contracting may be weighed: each is incorrect in its generality.
Does a later increase in value count towards the assessment of damages or loss in a case of mistake?
Later facts may in principle play a role. But an increase in value resulting from the removal of a risk does not erase the excessive purchase price: if the buyer had, with knowledge, bought for less, the buyer would also have benefited in full from that increase. The loss at the moment of purchase remains.
Supreme Court 6 February 2026, ECLI:NL:HR:2026:199
Cited case law
Supreme Court: ECLI:NL:HR:2010:BL0539 · ECLI:NL:HR:2026:199
Advocate General: ECLI:NL:PHR:2025:304
Courts of Appeal: ECLI:NL:GHSHE:2024:432