The expanded use of Open Source Software (OSS), and the expansion of the market caused by this adoption has led to a corresponding increase in the number of businesses acting as stakeholders in the field. Some of these are pure users of OSS technology but a great number are developers of such technology, and can be understood to have a substantial investment in this paradigm. It is reasonable to assume that such businesses are rational actors, and that their investment or contribution to the field implies a positive economic benefit either currently obtained or assumed as a return in the future. This paper analyzes how OSS affects Japanese IT companies’ business growth both through simple use and by deeper engagement as a stakeholder in OSS community. This is the first time that such a link between the utilization of OSS and economic growth has been explored in the context of Japan, and it can hopefully lay a foundation for further study regarding the real economic value of this approach to software.