 In November 2007, the SEC expanded the SRO registration of PDEx to cover the Inter-Professional Market, and in February 2008, its SRO authority was expanded to cover its members in all markets within the PDEx Trading Systems.Trading on the PDEx platform is done through a state-of-the-art trading engine called X-Stream that was developed by NASDAQ OMX.Trading Participants are provided a front-end system (the Fixed Income Trading Workstation, FITW) through which quotes can be entered and/or amended and where transactions are eventually executed.