The cobweb theorem reflects the ‘basic idea of carrying successive production, price, and production readjustments back and forth between the supply and demand curves’ and regards, in particular, the cases of continuous, divergent and convergent fluctuations. Among the first economists, who presented and used this model, were Henry Schultz, Jan Tinbergen, Umberto Ricci, Nicholas Kaldor, Wassily Leontief and Mordecai Ezekiel. The early cobweb models were applied primarily to explain the cyclic fluctuations of production and prices for some farming products such as corn, potato, hogs, milk cows, etc. The modern cobweb models are more sophisticated, being used not only for simple commodity markets, and also dealing with nonlinear dynamics theory. In the simple model illustrated by the curves of demand and supply, the cobweb path describes the fluctuation of a price, supply and demand on the competitive market of a certain commodity under conditions when a price is formed under influence of supply and demand; there is a time lag in the process of sellers’ adaptation to demand and, thus, the supply (quantity of production) in the current period t depends on the commodity price in the previous period (t-1). According to the cobweb model, in the case when the elasticity of demand is greater than the elasticity of supply, the convergent fluctuation occurs; the divergent fluctuation takes place when the elasticity of supply is greater than the elasticity of demand. We can compare the convergent fluctuation and the divergent fluctuation in the cobweb theorem with stable and unstable equilibrium correspondingly. In this paper the connection between the price distribution and the arrangement of the curves of demand and supply is presented. From this point of view, the arrangement of the curves of demand and supply, which generates the divergent fluctuation in the cobweb model, should describe the heavy-tailed price distribution. In its turn, the heavy tailed price distribution is connected with the growing market uncertainty and, thus, can signalize about oncoming instability and crisis. So, the paper considers, firstly, the influence of the financial sector on the decreasing elasticity of aggregate demand and, secondly, the role of financial sector in the appearing of heavy-tailed price distributions on the macroeconomic level.  The main hypothesis of the paper is illustrated by examples from the works of Mikhail Tugan-Baranovsky, Vilfredo Pareto, Joseph Schumpeter, John M. Keynes and Hyman Minsky.