ABSTRACT European regulatory networks are increasingly becoming crucial venues for European governance. They typically emerged as relatively loose groups of national authorities in charge of meta-regulating sectoral policies. However, in the medium term, they experienced dissimilar developmental patterns. On the one hand, some networks (such as the Committee of European Securities Regulators – CESR) have been progressively institutionalized, transformed into European agencies, and acquired considerable regulatory powers, including enforcement. On the other hand, other networks (such as the European Competition Network – ECN) remained more flexible networked organizations embodying a soft coordination approach. This article aims at mapping these divergent patterns and explore their determinants. To do so, we investigate the cases of CESR and ECN with a documentary and interview-based comparative inquiry. Results indicate that agencification has also been a strategy enacted by European institutions, using the financial crisis as a window of opportunity, to regain control over a powerful network – CESR – that came to constitute an increasingly autonomous layer of governance. Contrariwise, as ECN did not spin out of control, its trajectory exhibits a remarkable stability.