There is provided mechanisms for precoding over a beam subset. A method is performed by a network node. The method comprises exchanging reference signal information for a set of transmission beams or set of antenna ports with a wireless device. The method comprises acquiring, based on the reference signal information, information regarding which proper subset of transmission beams from the set of transmission beams to use for communication with the wireless device. The method comprises determining precoding weights for the proper subset of transmission beams or antenna ports based on the reference signal information.