Paper to be presented at the DRUID 2011 on INNOVATION, STRATEGY, and STRUCTURE - Organizations, Institutions, Systems and Regions at Copenhagen Business School, Denmark, June 15-17, 2011 Firms’ participation strategies and performances of OSS projects: an empirical analysis Cristina Rossi-Lamastra Management, Economics, and Industrial Engineering cristina1.rossi@polimi.it Francesco Rullani LUISS Guido Carli Department of Economics and Business frullani@luiss.it Evila Piva evila.piva@polimi.it Abstract Software firms? participation in Open Source Software (OSS) projects is a widespread phenomenon. Firms participate in the projects of collective software development created by the OSS community by varied participation strategies (i.e. offering sponsorships, writing and debugging code, testing the software, and so on). To date, investigations on firms? participation in OSS projects have mostly focused on firms? incentives to participate or on the effects of projects? participation on firms? performance. The present paper advances the received knowledge in that it addresses following research question: what is the impact, if any, of specific firms? participation strategies on OSS projects? performances?