Vertically Integrated Power System around the world is being restructured into Horizontally Distributed Deregulated Power System. In the deregulated power system, the power transactions plays a major role. Effective management of power transactions decides the secure and economic operation of power system. As the real time operation and control of deregulated power system is mainly based on transactions, it would be better if the system studies are also based on the power transactions. This study analyses the technical feasibility of ATC estimation using real power transactions. This study proposes a Support Vector Machine (SVM) based method for ATC estimation using real power transactions as inputs. To the best of the knowledge this is the first attempt to use real power transactions as inputs for ATC estimation using SVM. The proposed methods are tested on IEEE 24 bus Reliability Test System (RTS) and IEEE 118-bus System. The results are compared with Repeated Power Flow (RPF) results and the results of SVM Model developed using real power loads as inputs. © Medwell Journals, 2014.