The invention relates to compositions for the production of thermoplastic moulding materials, where the compositions comprise the following constituents: A) at least one polymer selected from the group consisting of aromatic polycarbonate, aromatic polyester carbonate and polyester, B) at least one anhydride-functionalized ethylene-a-olefin-copolymer or anhydride-functionalized ethylene-a-olefin terpolymer with a weight-average molar mass Mw determined by high-temperature gel permeation chromatography using ortho-dichlorobenzene as solvent against polystyrene standards of 50000 to 500000 g/mol, C) at least one rubber-modified graft polymer, D) glass fibers, and also to a process for the production of the moulding materials, to the moulding materials themselves, to the use of the compositions or moulding materials for the production of mouldings, and to the mouldings themselves.