Adequacy is an objective criterion for the attribution of damages which limits liability for a particular result. A damage is only adequately caused if the general suitability of the cause to cause the damage does not objectively lie outside the general human experience. This is intended to exonerate the perpetrator and not to hold him liable if, on the basis of life experience, he did not objectively have to reckon with the occurrence of the damage because the damage occurred only as a result of an extraordinary concatenation of circumstances which do not occur from the ex ante point of view of a reasonable and prudent person. The internal justification of the adequacy is intended to prevent completely unforeseeable consequences from being reasonably thought of as no more than controlled by man, so that these should not be attributed to the perpetrator. The perpetrator is liable for accidental consequences only if he had to reckon objectively with the possibility of occurrence.
In the decisions 7 Ob 48/12b and 7 Ob 121/14s based on the ECJ decision Kone AG, C-557/12, the Supreme Court dealt with the adequacy in terms of umbrella pricing.
Details can be found in the book Michael BRAND, Schadenersatz im Kartellrecht, starting on page 202.