From Open Warfare to Strawman’s Anonymity: Motives and Strategies Behind Patent Opposition at EPO

Patent opposition allows any firm to challenge the validity of newly granted patents. How- ever, initiating this procedure discloses strategic information to competitors that firms might want to avoid, particularly so whether the opponent firm is off the radar of its competitor. This creates a trade-off between the possibility to invalidate a competitor’s patent and the disclosure of valuable and strategic information. We study this trade-off by investigating the cases in which firms challenge competitor’s patent anonymously, engaging a “strawman”. Using a novel dataset of patents opposed at the European Patent Office (EPO) between 2000 and 2017, combined with firm-level information, we assess what drives a firm to engage in this strategy. We find that firms hide behind a strawman and anonymously attack patent owners to prevent signalling to the patent owner their interest in a field that is marginal to their core activity.