US asset managers are growing increasingly nervous about rhetoric from Europe’s main securities regulator. Recent guidance around Brexit is prompting concerns that existing arrangements allowing their staff based outside the continent to manage EU-domiciled funds could be under threat.

Fund managers based in the US that use a European framework to sell Luxembourg and Dublin-domiciled funds, known as Ucits, to European investors rely heavily on existing EU legislation to allow portfolio management staff based outside the bloc to oversee these strategies, otherwise known as delegation.