The higher aggregate prevalence of loan over bond funding in Europe is not only driven by the well-documented differences in financial market settings but also strongly shaped by different firm characteristics. The European economy is more fragmented than the U.S. economy, and thus features a different firm distribution in terms of size and collateral availability. I estimate that if all European firms had access to a financial market like the U.S. market, their aggregate bond funding share would remain significantly smaller. This counterfactual suggests a limited potential for European corporate bond markets in the short and medium term.