Using data from the German Community Innovation Survey (CIS) from 2008, we analyze whether innovation partnering increases the risk of experiencing infringement of intellectual property (IP). The results show that depending on types of IP innovation, partnerships increase the risk of infringement by up to 37% compared with the average risk in the sample. The results suggest that this massive increase can be reduced by IP rights and contracts to govern the partnerships. Yet, we show that formal protection mechanisms do not eliminate the sources of opportunistic infringement, because that infringement in innovation partnerships more commonly relates to the infringement of formally unprotected IP, such as tacit knowledge and know‐how.