Polymer ammonium borates having a molecular weight from about 5000 to about 500,000 and obtained by homopolymerization of monomers, such as, for example, diallyldialkylammonium chloride, and by copolymerization of mixtures of two monomers, such as, for example, diallyldimethylammonium chloride and diallylmethyloctylammonium chloride, having molar monomer ratios of about 0.5:0.5 to about 0.95:0.05 in the copolymer, followed, if desired, by anion exchange, and mixtures of these compounds. Polymer ammonium borates according to the invention are suitable as colorless charge-control agents in toners and developers for electrophotographic recording processes and as charge-improving agents in powders and coatings for surface coating.