An APEO-free*, solvent-free*, hydrophobically-modified alkali-soluble (HASE) rheology modifier for waterborne architectural coatings. The product offers a much more Newtonian rheology profile than cellulosic thickeners, enabling lower viscosity in low-shear conditions and higher viscosity in high-shear conditions. It is supplied as a high solids, low viscosity liquid for ease of use in manufacturing.