The present invention relates to a process for the production of impact-modified filled polycarbonate compositions and molding compositions. A process of the present invention involves: (i) mixing the CNT (component C) with rubber-containing vinyl copolymer (component B) and/or rubber-free vinyl copolymer (component D) on a twin screw extruder, to obtain a CNT masterbatch, (ii) mixing the CNT masterbatch with polycarbonate (component A) and optionally with Component B and/or Component D and optionally with an additive on a twin screw extruder. A polycarbonate composition prepared according to the present invention does not experience degradation of the molecular weight of the polycarbonate during compounding a compared to processes known in the art.