Method of improving shear stability of highly concentrated aqueous adhesive polymer compositions, wherein the aqueous adhesive polymer composition comprises more than 50% by weight, preferably at least 56% by weight, of at least one adhesive polymer which has been prepared by emulsion polymerization and which is dispersed in the aqueous adhesive composition, wherein the adhesive polymer has been made by free-radical emulsion polymerization of a monomer mixture comprising a) at least 60 wt.%, based on the total amount of monomers, of at least one monomer selected from the group consisting of C1 to C20 alkyl acrylates, C1 to C20 alkyl methacrylates, vinyl esters of carboxylic acids containing up to 20 carbons, vinylaromatics having up to 20 carbons, vinyl halides, vinyl ethers of alcohols containing 1 to 10 carbons, ethylenically unsaturated nitriles, aliphatic hydrocarbons having 2 to 8 carbons and one or two double bonds, and mixtures of these monomers, b) from 0.1 to 10 wt.%, based on the total amount of monomers, of at least one monomer having at least one acid group; c) optionally at least one further monomer, different from the monomers a) and b); said method comprises treating the aqueous adhesive polymer composition with at least one anion exchange resin and not treating the aqueous adhesive polymer composition with a cation exchange resin or with a mixed bed ion exchange resin. wherein the aqueous adhesive polymer composition comprises more than 50% by weight, preferably at least 56% by weight, of at least one adhesive polymer which has been prepared by emulsion polymerization and which is dispersed in the aqueous adhesive composition, wherein the adhesive polymer has been made by free-radical emulsion polymerization of a monomer mixture comprising a) at least 60 wt.%, based on the total amount of monomers, of at least one monomer selected from the group consisting of C1 to C20 alkyl acrylates, C1 to C20 alkyl methacrylates, vinyl esters of carboxylic acids containing up to 20 carbons, vinylaromatics having up to 20 carbons, vinyl halides, vinyl ethers of alcohols containing 1 to 10 carbons, ethylenically unsaturated nitriles, aliphatic hydrocarbons having 2 to 8 carbons and one or two double bonds, and mixtures of these monomers, b) from 0.1 to 10 wt.%, based on the total amount of monomers, of at least one monomer having at least one acid group; c) optionally at least one further monomer, different from the monomers a) and b); a) at least 60 wt.%, based on the total amount of monomers, of at least one monomer selected from the group consisting of C1 to C20 alkyl acrylates, C1 to C20 alkyl methacrylates, vinyl esters of carboxylic acids containing up to 20 carbons, vinylaromatics having up to 20 carbons, vinyl halides, vinyl ethers of alcohols containing 1 to 10 carbons, ethylenically unsaturated nitriles, aliphatic hydrocarbons having 2 to 8 carbons and one or two double bonds, and mixtures of these monomers, b) from 0.1 to 10 wt.%, based on the total amount of monomers, of at least one monomer having at least one acid group; c) optionally at least one further monomer, different from the monomers a) and b); said method comprises treating the aqueous adhesive polymer composition with at least one anion exchange resin and not treating the aqueous adhesive polymer composition with a cation exchange resin or with a mixed bed ion exchange resin.