By integrating data on scientific publications from the RISIS publication database with data on European Universities from the European Tertiary Education Register and data on US universities, researchers from USI, Lugano, and from the University of Turin have shown a strong relationship between universities’ revenues and their volume of publications and citations. This relationship implies that international rankings are largely by and large measures of wealth. Further, the study shows that three characteristics differentiate the US system, i.e. a) a significantly higher level of resources, b) a clearer distinction between education-oriented institutions and doctoral universities, and c) a higher concentration of resources among doctoral universities Accordingly, a group of US universities receive a much larger amount of resources and have a far higher number of publications and citations when compared to their European counterparts. These results demonstrate that the ‘transatlantic gap’ in research excellence is largely associated with differences in resources. Implications for public policies and institutional evaluation are discussed.