Water-soluble copolymers based on olefinic sulfonic acids, olefinic dicarboxylic acids, vinyl amides and vinyl ethers and/or allyl ethers and/or bisacryl derivatives are described as well as processes for their production and the use of these copolymers as water retention agents, thickeners or anti-segregation agents for aqueous building material systems that contain hydraulic binding agents such as cement, lime, gypsum, anhydrite etc. or for clay suspensions preferably based on bentonite.