Abstract: Computerized trading system adapted to handle trading of Exchange Traded Funds (ETFs), where each ETF comprises portfolio securities represented by portfolio security data entities stored in a portfolio trading database, the system further comprises a control device connected to, and controlling, said portfolio trading database, at least one market participant input device, and a fund manager input device both being connectable to the control device. Each input device being connected to a display device provided with a graphical user interface, wherein the market participant input device(s) is/are adapted to receive transaction orders from market participants and to transfer said orders in the form of transaction signals to said control device that initiates and performs said transactions.