In a monetary economy of production, Say’s law is invalid for several reasons. Based on some refutations, it is possible to state that revenues generated by the production process are structurally lower than the supply price of production, which means that firms create insufficient purchasing power to buy what they produce. Herein, we study the dynamics of such an economy and obtain two main results. First, the long-term debt level of that economy must increase during a growth phase to enable demand to grow at the same pace as supply. Second, because of the repayment of this debt, the gap between supply and net revenues generated by the production process widens along a growth phase. JEL Classification: E12, E2, E30, E42, G21