A process of preparing brominated anionic styrenic polymer having a reduced volatile bromobenzene content, which process comprises: A) concurrently feeding into a reaction zone components comprised of (i) a brominating agent, (ii) aluminum halide catalyst in which the halide atoms are bromine or chlorine or both, and (iii) anionic styrenic polymer having a GPC number average molecular weight in the range of 2000 to 30,000 in the form of a solution or slurry in a solvent to form a reaction mixture, wherein said components are fed as two separate feeds, one feed of which contains no more than two of (i), (ii), and (iii), and another feed of which contains the third of (i), (ii), (iii) either individually or in combination with no more than one other of (i), (ii), and (iii), to thereby form a reaction mixture containing a liquid phase, and maintaining said reaction mixture at 10°C or less whereby bromination of anionic styrenic polymer occurs, the components being proportioned such that the amount of aluminum halide being fed is at 0.8 mole percent or less in relation to the molar amount of aromatic monomer units in the anionic styrenic polymer being fed, and such that the dried brominated anionic styrenic polymer referred to in C) hereinafter will have a bromine content measured according to the method indicated in the experimental section, in the range of 60 to 71 wt%; B) deactivating the catalyst in, and washing away bromide ions and catalyst residues from 1) substantially the entire reaction mixture or 2) portions of the reaction mixture that have exited from the reaction zone; and C) recovering brominated anionic styrenic polymer product from the reaction mixture and drying such product whereby the dried brominated anionic styrenic polymer has a bromine content in the range of 60 to 71 wt% and a volatile bromobenzene content which is no more than 600 ppm (wt/wt). A) concurrently feeding into a reaction zone components comprised of (i) a brominating agent, (ii) aluminum halide catalyst in which the halide atoms are bromine or chlorine or both, and (iii) anionic styrenic polymer having a GPC number average molecular weight in the range of 2000 to 30,000 in the form of a solution or slurry in a solvent to form a reaction mixture, wherein said components are fed as two separate feeds, one feed of which contains no more than two of (i), (ii), and (iii), and another feed of which contains the third of (i), (ii), (iii) either individually or in combination with no more than one other of (i), (ii), and (iii), to thereby form a reaction mixture containing a liquid phase, and maintaining said reaction mixture at 10°C or less whereby bromination of anionic styrenic polymer occurs, the components being proportioned such that the amount of aluminum halide being fed is at 0.8 mole percent or less in relation to the molar amount of aromatic monomer units in the anionic styrenic polymer being fed, and such that the dried brominated anionic styrenic polymer referred to in C) hereinafter will have a bromine content measured according to the method indicated in the experimental section, in the range of 60 to 71 wt%; B) deactivating the catalyst in, and washing away bromide ions and catalyst residues from 1) substantially the entire reaction mixture or 2) portions of the reaction mixture that have exited from the reaction zone; and 1) substantially the entire reaction mixture or 2) portions of the reaction mixture that have exited from the reaction zone; C) recovering brominated anionic styrenic polymer product from the reaction mixture and drying such product whereby the dried brominated anionic styrenic polymer has a bromine content in the range of 60 to 71 wt% and a volatile bromobenzene content which is no more than 600 ppm (wt/wt).