Financing of a project is often done through a combination of debt and equity. Debt is preferred as it has the advantage of retaining control of the company and having a finite payback period, but it can be very difficult to secure debt for 100% of the project cost without some equity to use as debt collateral. Conversely, equity can be easier to secure, but might have a higher cost because either: a) the equity cost (discount rate) is higher, b) unlike debt interest, equity interest is not tax deductible in the U.S., and c) equity cost usually has indefinite repayment terms. A 60%/40% debt/equity financing scheme is commonly assumed.