A Corporation which wants to calculate the net present value of an investion needs a discount rate. Typically, it takes the long-term capital market interest rate for this purpose. For financing the corporations investions, it has to decide which credit instruments cause which capital costs. This means it has to get informations about capital market interest rates as well. To manage the daily cash flows with a cash management system and to optimize cash balance, it needs capital market interest rates to know about his opportunity costs of cash balance a third time.