Abstract: On the basis of trading information shared by a securities company and a customer executing margin trading with the securities company, all positions or stocks in a customer account are managed to automatically execute a first loss cut at a first loss cut rate for selling the stocks or the like at the market and a second loss cut rate for selling the stocks and the like outside the market to execute the loss cut evenly for each open position in the customer account by the specified first and second rates. Indication of execution of the loss cut is provided to the customer. Specified individual open positions in the customer account may be managed to automatically execute the loss cut. This system can be used in cash trading for held stocks.