Here I want you to read about what is a business cycle in order to be able to predict fluctuations and know when to sell or buy assets. All informations are from wikipedia.pl
The term business cycle (or economic cycle or boom-bust cycle) refers fluctuations in aggregate production, trade and activity over several months or years in a market economy.The business cycle is the upward and downward movements of levels of gross domestic product (GDP) and refers to the period of expansions and contractions in the level of economic activities (business fluctuations) around its long-term growth trend.These fluctuations occur around a long-term growth trend, and typically involve shifts over time between periods of relatively rapid economic growth (an expansion or boom), and periods of relative stagnation or decline (a contraction or recession).
Business cycles are usually measured by considering the growth rate of real gross domestic product. Despite being termed cycles, these fluctuations in economic activity can prove unpredictable.
The first systematic exposition of periodic economic crises, in opposition to the existing theory of economic equilibrium, was the 1819 Nouveaux Principes d'économie politique by Jean Charles Léonard de Sismondi. Prior to that point classical economics had either denied the existence of business cycles, blamed them on external factors, notably war,or only studied the long term. Sismondi found vindication in the Panic of 1825, which was the first unarguably international economic crisis, occurring in peacetime.