This paper is focused on the implementation of the presumption of harm for cartels, as formulated in art. 17.2 of Directive 2014/104/EU. In most Member States the overcharge is presumed to be 0% unless proven otherwise. In two Member States this is 10% and in one it is 20%. These can be considered as three defaults. Damages litigation may lead to under- or overcompensation. Achieving full compensation is rather a coincidence. If harm is de facto substantially lower (higher) than the default, the infringer (victim) has an incentive to prove the actual level of harm. Different choices regarding the presumptions of harm imply a difference in the weighing of under- and overcompensation. A 0% default suggests that preventing overcompensation is the dominant goal. A 10% default will be more effective than a 0% default in serving the compensatory function.