European brokers that are conjuring up plans to sidestep Mifid II's dark pool rules by partnering with proprietary trading firms are going "against the very spirit and idea" of legislation designed to promote transparency, according to the German MEP Markus Ferber.

In a December 13 letter to Valdis Dombrovskis, the EU's Commissioner for financial services, seen by FN, Ferber said such developments were "quite concerning" and called for the Commission to seek the advice of the European Securities and Markets Authority on the matter.