The exact market optimization formulations currently in use in US RTO/ISO-managed wholesale power markets are proprietary. This chapter describes, in simplified form, the logical flow of daily day-ahead market (DAM) and real-time market (RTM) operations in current US RTO/ISO-managed wholesale power markets. Employing net surplus concepts, it uses the DAM model to examine how total net surplus (TNS) is currently extracted in US RTO/ISO-managed DAMs. The chapter also uses the TNS extraction findings, together with RTO/ISO net surplus allocation precepts, to examine the relationship between seller market power and market inefficiency in current US RTO/ISO-managed DAMs. It discusses how the outcomes of privately negotiated physical bilateral contracts are scheduled in these markets. The chapter illustrates how power traders can secure transmission support for these trades in current ISO DAMs.