In this paper we use a size and industry matched sample of over 1,900 UK and US businesses for the period 2004–05 in the manufacturing and business services sectors to analyse the relative “strength” of the university–industry ecosystems in which these firms operate in the two economies. Our analysis shows that in both countries universities per se play a quantitatively smaller role as a source of knowledge for business innovation than either the business sector itself or a variety of organisations intermediating between the university and business sectors. Our analysis reveals a much more diffuse university–industry ecosystem in the UK in which a higher proportion of businesses claim links external to themselves in their pursuit of knowledge for innovation and a higher proportion report directly connecting with universities. US firms are more likely to access knowledge through a combination of business and intermediary sources and are less likely to have established formal collaborative or partnership agreements in the 3 years prior to the survey. We also find, however, that a higher proportion of US firms place a very high value on the connections they have with universities and are much more likely to commit resources to support such innovation related university interactions. A similar pattern of diffuse but weaker links characterise the supply of public sector financial assistance for innovation in our sample firms. UK firms are more likely to be in receipt of assistance, but receive far less per firm in absolute terms and relative to their R&D expenditures. It appears that the UK university–industry ecosystem is characterised by a greater width than quality of interaction.