Published online by Cambridge University Press: 20 April 2012
We will be considering a productive investment project or financial security which yields a sequence of cash flows, positive or negative, over time. Let a1 (dollars) be the cash flow from the project at time t, where t takes the values 0, 1, 2,…, n. Given the known cash flows at from the project, and a known market rate of interest, i per period, at which money may be borrowed or invested, a common procedure is to accept the project if its present value P is greater than zero, where
An internal rate of return of the project is defined to be a solution of the equation
in (− 1, ∞), if, of course, one exists.