It is established practice in the Netherlands that the extent of damage that occurs as a consequence of a tort need not be proven up to the hilt.
It is sufficient to show convincingly that damage might have occurred. It is then to a court to judge the extent of damage. For this, the court may determine the difference between the actual situation being the consequence of the tort) and a hypothetical situation occurring when the tort had not taken place. The court is not bound to the normal rules for providing facts and evidence.
The Court of Appeal in The Hague recently decided that also loss of profits occurring after the termination of a tort may require compensation. Snoeks was the holder of a European patent related to installation kits for rear seats in trucks, which was validated in the Netherlands. Snoeks enforced its competitors, collectively called A&T, to stop selling their competing kits in 2003. The Dutch part of the European patent was revoked in 2005, against which Snoeks filed an appeal. The European patent was revoked in its entirety by the EPO in 2007. A&T subsequently started a lawsuit to obtain compensation of damages due to unlawful enforcement of the patent.
Most of the compensation claims were rejected by the Court of First Instance. However, the Court of Appeal awarded not only damages that occurred in the period up to the revocation of the Dutch part of the European patent in 2005, but also allowed a claim for loss of profits after the revocation of the Dutch patent. The court held it likely that product development and marketing and sales activities of A&T were delayed because of the uncertainty whether the revocation of the Dutch patent was maintained in appeal.