The diagram M-C-M shows how capitalists increase and maintain wealth. Here, “M” stands for money, “C” for commodities, and “M’” for a larger amount of money than what was originally invested. This process starts with a capitalist using money (M) to buy commodities (C), like materials or labor. Then, they use those commodities to produce goods or services. When they sell these goods or services, they get more money back, which is M’ (the original money plus extra, known as surplus value).
Surplus value is created through labor power—the workers’ ability to work. Capitalists pay workers for their labor, but the workers produce more value than they receive in wages. This extra value, or surplus labor, is what capitalists keep, transforming it into profit.
In other words, money becomes capital when it is used to buy labor and materials that produce goods or services for profit. This cycle, M-C-M, is how capitalists continuously grow wealth, by investing in production, extracting surplus value from workers, and generating more money than they started with. This process keeps the capitalist class wealthy, as they constantly reinvest to make even more.