We study the underpricing of firms listed on the two largest EuroNM stock exchanges, the Neuer Markt of Germany and the Nouveau Marché of France. We find that the high underpricing in these two markets - contrary to the evidence on the US - is not driven by insiders' selling behaviour. However, the large underpricing is caused by the high degree of riskiness of the issuing firms and by the partial adjustment phenomenon of offer prices to compensate institutional investors for the truthful revelation of their demand for the shares. For France, lock-up agreements act as substitutes to underpricing, but not so for Germany. We also explore the reasons for the large difference in underpricing between the German and the French IPOs: German firms are more underpriced because they are riskier, have larger price revisions, have less stringent VC lock-up contracts, and go public mostly during the hot issue period when the general level of underpricing in all IPO markets is substantially higher. © 2009 Elsevier Inc. All rights reserved.