The thermoplastic molding composition comprises: a) as component A, from 0 to 97.9% by weight of one or more (methyl)styrene-acrylonitrile copolymers which do not have any units derived from maleic anhydride, and which have an intrinsic viscosity smaller than 85 ml/g, b) as component B, from 1 to 98.9% by weight of one or more (methyl)styrene-acrylonitrile copolymers which have, based on the entire component B, from 0.5 to 5% by weight of units derived from maleic anhydride, c) as component C, from 1 to 75% by weight of glass fibers, d) from 0.1 to 20% by weight of one or more flow promoters, selected from d1) as component D1, at least one highly branched or hyperbranched polycarbonate with an OH number of from 1 to 600 mg KOH/g of polycarbonate (to DIN 53240, part 2), d2) as component D2, at least one highly branched or hyperbranched polyester of AxBy type, where x is at least 1.1 and y is at least 2.1, d3) as component D3, alkyl acrylate oligomers with a weight-average molar mass in the range from 1200 to 4000 g/mol, e) as component E, from 0 to 40% by weight of further fillers, or rubbers, and/or further additives, where the total amount of components A to D and, if present, E is 100% by weight.