Tendency of the rate of profit to fall

The tendency of the rate of profit to fall (TRPF) is a theory in the crisis theory of political economy, according to which the rate of profit—the ratio of the profit to the amount of invested capital—decreases over time. This hypothesis gained additional prominence from its discussion by Karl Marx in Chapter 13 of Capital, Volume III, but economists as diverse as Adam Smith, John Stuart Mill, David Ricardo and William Stanley Jevons referred explicitly to the TRPF as an empirical phenomenon that demanded further theoretical explanation, although they differed on the reasons why the TRPF should necessarily occur.

Geoffrey Hodgson stated that the theory of the TRPF "has been regarded, by most Marxists, as the backbone of revolutionary Marxism. According to this view, its refutation or removal would lead to reformism in theory and practice". Stephen Cullenberg stated that the TRPF "remains one of the most important and highly debated issues of all of economics" because it raises "the fundamental question of whether, as capitalism grows, this very process of growth will undermine its conditions of existence and thereby engender periodic or secular crises."