Investment decisions in the theory of finance: some antinomies and inconsistencies

The net-present-value rule is a pillar of modern finance theory. As known, it is a capital budgeting rule. Finance theory prescribes the investor to compare the opportunity in hand with an asset of equivalent risk, i.e. to discount cash flows with a risk-adjusted rate of return. This paper aims at showing that inconsistencies and antinomies arise when applying the above-mentioned rule. Further, it turns out that it is actually impossible to compare alternatives equivalent in risk and any decision maker cannot prevent herself to violate the above tenet.