Open Innovation has changed the traditional conceptualization of innovation as an internal process by leveraging on collaborations among several participants outside the boundaries of the firm. The involvement of large number of contributors makes more likely the collection of “extreme outcomes”, that are exceptional ideas with high potential value for companies. Thanks to the advancement in information technologies, crowdsourcing boost the idea generation phase of the innovation process by leveraging the collective intelligence of dispersed individuals collaborating through web-based platforms. Although extant research has theorized the beneficial effects of crowdsourcing on R&D outcomes, its effect on firm performance has not been investigated yet by empirical studies. In order to fill this gap, we build on signaling theory by looking at stock market reactions to crowdsourcing announcements. Our findings show that crowdsourcing announcements trigger positive price shocks, and we also highlight which firm-specific factors can moderate such relationship.