The function of blockchain systems used in financial markets might at some future point in time place them among critical infrastructures such as settlement systems and CCPs. Blockchain financial networks would provide a service that would not be easy to replace should they fail to function properly. As networks linking a multitude of financial market actors, potentially of different types, they are also highly interconnected. Hence,, such networks are destined to become important in terms of financial stability once they have attracted a certain volume of assets and a critical number of users. It might therefore be necessary to regulate blockchain financial networks with a view to ensuring that they are resilient and do not contribute to systemic risk but, ideally, help to reduce it.