39. The cost of capital for current assets (S31.2) Look again at Problem 10, which asked you to assume that the 6.5% interest rate was the opportunity cost of capital. Was that a reasonable assumption? What should the opportunity cost of capital for inventory depend on? Would it ever make sense to use the firm’s overall weighted average cost of capital? What if the inventory was not spare parts for a railroad, but a risky commodity—for example, crude oil stocks held as raw material for a petrochemical plant? Discuss and explain.