Part du profit dans le revenu : 1/3, une valeur de référence ?

The distribution of income between the capital and the labor is considered as a major problem since Ricardo [1817]. A value of about 1/3 for the profit share in income is often met and is a stylized fact for many growth models. This article proposes a theoretical explanation based on an endogenous and keynesian growth model; the starting point is an idea of Kaldor [1972], economic growth being the result of a chain-reaction between increases in supply and demand. These increases are linked to the investments decided by the entrepreneurs and depend on the effective demand and on the marginal efficiency of the capital. It is demonstrated that the “magic number” of 1/3 is theoretically justified when wage growth is independent of employment growth. A profit share in income higher than 1/3 leads to an economic slowdown. The theoretical lessons are consistent with the reality of the U.S. economy from 1961 to 2018 and with the stylized facts highlighted by economists (Verdoorn, Okun, Ferri, Bhaduri-Marglin, Piketty).