The investments represent the primary factor in the development strategy of an economic entity. The role of the investments begins with their purpose, meaning that the investments involve the increasing of a stock portfolio. The research methodology that is approached in this article is based on the analysis of two factors: net present value and internal rate of profitability. Capital budgeting in an investment project that, without a prior analysis of the efficiency of such a decision, can lead to the total or partial loss of the invested capital. An investment project is efficient if the net present value is positive and has a larger value. An investment project becomes more profitable as the value of the internal rate of profitability gets higher. If the two factors are correctly interpreted they lead to exactly the same conclusions regarding the determination of an investment profitability. We can conclude that the two efficiency factors are complementary, their simultaneous use leading to a better grounding of the investment decision than their separate use.