Processing and charting security exchange trading and market information shows security traders if current transactions originated as buy orders or sell orders, and simultaneously indicates traded quantity. Security exchange trading information is received that includes the price, volume and time of each trade. In addition, security exchange market information is received from buyers, specifying bide prices and quantities, and from sellers, specifying asking prices and quantities. The security exchange trading and market information is processed simultaneously and displayed as a continuously updated real-time chart depicting the exchange auction process whereby buyers and sellers agree to trade at specified prices, including details of individual transactions. The chart is formed by plotting each trade at the price traded, and for each plot point shows a distinctive icon indication whether the transaction was initiated by a buyer or seller.