This paper deals 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. For choosing between 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. Relations
with other criteria such as Modified Internal Rate of Return, average IRR, Cash Multiple, and
Profitability Index are provided.
Theoretically, the AROI approach constitutes a link between arbitrage choice theory and corporate
investment theory, and shows that explicit discounting is not necessary for measuring economic
profitability. Practically, the AROI is a user-friendly, easy-to-compute rate of return derived from
the same set of data required by the net present value (NPV). Also, it does not incur the
difficulties met by the internal rate of return (IRR): in particular, it is unique and it is based
on economically significant capital values (i.e., market-driven values). As such, the AROI
significantly expresses the efficiency of the
project's invested capital.