A method for operating a wind power installation is provided. The wind power installation comprises an aerodynamic rotor with rotor blades, where the rotor can be operated with a variable rotor rotation speed. The wind power installation outputs an output power generated from wind for feeding into an electrical supply grid. The wind power installation can be operated in a normal operating mode without power reduction and in a reduced operating mode with power reduction, in which a specified power reduced with respect to a rated installation power is specified. When operating in the reduced operating mode for wind speeds above a rated wind speed, at least in one rotation speed increase region, the wind power installation increases its rotor rotation speed as the wind speed rises further.