The introduction of a leniency program may encourage multi-product firms involved in price cartels on several markets to adopt a decentralized organization. This slows down antitrust investigations. The discovery of another cartel in the course of an investigation into a first cartel is thus postponed. This delay gives firms more time to apply for leniency for other cartels not yet discovered. A decentralized organization thus enables a greater reduction in fines to be obtained when firms wish to benefit from the leniency program. It does, however, have the disadvantage of introducing intra-firm competition and reducing collusion prices. A leniency program can therefore have a marginal deterrent effect by modifying firms' internal organization, thereby reducing collusion prices. A larger fine reduction can reinforce this marginal deterrent effect. However, it can also produce an anti-competitive effect by enabling the formation of new cartels.