Based on the critical case of ABB, this paper questions the relevance of using patents with multiple inventors from different countries ("cross-country patents") as an indicator of international R&D collaboration. The study shows that less than half of ABB's cross-country patents are the result of international R&D collaboration as described by one of the more inclusive definitions found in previous literature. Only a third of the patents are the result of joint R&D activities between different MNC subsidiaries or firms. We also discuss the implications of our study for the assignment of patents to countries based on inventor addresses.