What is the real value that Open Source has brought to the economy? This is not a peregrine question. Since most of the current evaluation methods are based on assessing “sales”, that is direct monetization of OSS, we are currently missing from this view the large, mostly under-reported and underestimated aspect of open source use that is not “sold”, but for example is directly introduced through an internal work force, or in services, or embedded inside an infrastructure. The author will present a summary of recent research on macroeconomic-based estimates, including effects related to local reinvestments and efficiency.