To understand you must check the following equations:
Total Cost of a project = Explicit costs + Implicit costs …(1)
Economic profit = 0 …(2)
Accounting profit > 0 …(3)
Normal profit = Implicit costs …(4)
Implicit costs = Opportunity costs …(5)
Let’s talk about this:
A project must have always an accounting profit > 0 to be taken (3), right? It is strightforward.
But, accountability system only considers Explicit Costs which are shown in the P&L. What about the Implicit costs? You know now that it is the same than opportunity costs (5), thats why when we valorize a project we consider opportunity costs too. We consider Total Cost (1).
Since we consider always Total Cost, we cannot look at accounting profit only, we look at economic profit (2) which must be =0 to the project be taken. This is like the TIR >= WACC, if not, the economic profit is <0. Do you get it now?
The economic profit is =0 because it considers total cost, and covering the opportunity cost is Money in the pocket of the investor, so do not confuse economic profit with accounting profit. The nominal wealth and economic wealth are different. If the project covers the opportunity costs in its net revenue, the project is taken.
In an efficient economy, when you get an economic profit of zero you are in a Paretto Efficient point, you cannot be better, but you can be worse instead, that’s why the markets move. Some markets give a positive economic profit for a limited time, but the companies movements make that economic profit back to the zero level. This adjustments are done in a macro way and seen in the long-run, while in the short-run the companies are looking for positive economic profits or at least a zero economic profit.
Any question, please reply.
Regards