When a firm takes on a new capital budgeting project, it typically must increase its investment in receivables and inventories, over and above the increase in payables and accruals, thus increasing its net operating working capital. Since this increase must be financed, it is included as an outflow in Year 0 of the analysis. At the end of the project's life, inventories are depleted and receivables are collected. Thus, there is a decrease in NOWC, which is treated as an inflow.