In this paper, an adaptive zonal pricing methodology is proposed by employing phase-shifting transformers (PSTs) for large power systems. The proposed methodology is applicable for the commercially predefined zones. Commercially predefined zones can be easily identify in the countries like India. The zonal transmission networks (ZTNs) are to be connected to a central transmission network (CTN) through PST. The CTN includes all the potentially congested transmission lines. Irrespective of the system configuration, each zone can be represented as a single node in the locational marginal calculation over the CTN. The loss adjustment within a ZTN can be carried out on pro-rata basis by means of distributed slack power flow analysis. The phase shifters are employed for the purpose of voltage angle recovery. The use of phase shifters can be minimized by properly selecting the angle reference for each subnetwork. The effectiveness of the proposed methodology is demonstrated through a case study. © 2015 IEEE.