Systems and methods that provide charging for supplemental content in a data flow separately from other content in the data flow. One embodiment comprises a network element of a Packet-Switched (PS) network that serves mobile User Equipment (UE). The network element receives a data flow of packets for a download of content requested by the UE, and identifies supplemental content in the data flow not requested by the UE, such as advertising content. The network element generates a charging request, inserts charging information for the supplemental content in the charging request, and transmits the charging request to a charging system so that the supplemental content can be charged separately from other content of the data flow.