Aggregate Return on Investment for Investments under Uncertainty

This paper deals with with capital budgeting decisions under uncertainty. We present an Aggregate Return On Investment (AROI), obtained as the ratio of total (undiscounted) cash flow to total invested capital and show that it is a genuine rate of return which, compared with the risk-adjusted cost of capital, correctly signals wealth creation. The AROI exists and is unique and, for two mutually exclusive projects, we derive an incremental AROI and an incremental risk-adjusted cost of capital, by means of which two unequal-risk projects can be correctly compared. Iterating the incremental procedure, we show that the AROI approach correctly ranks any bundle of different-risk competing projects.