We study the effect of encouraging private actions for breaches of competition law. We develop a model in which a plaintiff, who may have private information about whether a breach of law has been committed, decides whether to open a case against a defendant. If opened, the case may be settled...

The paper makes two related contributions. First, and in contrast with the rich body of literature on collusion with (mainly perfect) substitutes, it derives general results on the sustainability of tacit coordination for a class of nested demand functions that allows for the full range between...