A thermoplastic resin composition comprising: (a) Alkylene aryl polyester copolymers having metal sulfonate units represented by the formula IA: ##STR1## or the formula IB: (M.sup.+n O.sub.3 S).sub.d --A--(OR"OH).sub.p where p=1-3, d=1-3, p+d=2-6, n=1-5, and A is an aryl group containing one or more aromatic rings where the sulfonate substituent is directly attached to an aryl ring, R" is a divalent alkyl group and the metal sulfonate group is bound to the polyester through ester linkages; (b) An essentially amorphous polycarbonate, polyester carbonate or polyarylate polymer containing recurring units of the formula II: ##STR2## wherein Ar is divalent aromatic residue of a dicarboxylic acid or mixture of dicarboxylic acids and Ar' is the divalent aromatic residue of a dihydric phenol or mixture of dihydric phenols. The composition may further comprise acidic phosphorus based quenchers, rubbery impact modifiers, mineral fillers or reinforcements.