THE MECHANISM OF BANK INTEREST RATE FORMATION AT THE MACROECONOMIC LEVEL AND ITS ECONOMIC AND MATHEMATICAL MODEL

It is shown that, as of today, the issue “interest rate and factors affecting it” is described in sufficient detail in terms of identifying and classifying these factors. However, both classical and modern theories consider the interest rate from the point of view of relations between economic agents: the owner of the funds (creditor) and the entity experiencing the need for additional funds (borrower) without singling out the banks. The bank interest is considered exclusively at the microeconomic level as the fundamental rate, adjusted depending on the conditions for granting a loan or attracting a deposit and the financial condition of a bank. However, the issue of the fundamental rate – the rate formed at the macroeconomic level – remains unresolved. Taking decision to set the interest rate, banks pursue two goals: profit maximization and risk management. The author substantiates the idea that the risk factors and effective use of funds raised are crucial for the formation of the fundamental rate. It is shown that the basic factor of the bank interest formation, which combines the elements of risk and profitability, is bank liquidity. At the same time, under the influence of the laws of the behavioral economy, the linear influence of liquidity is transformed into an ellipsoidal one. It is analyzed that subjective factors (the Central Bank rate and its profitability) are the efficiency factors, and their effect on the interest rate is manifested in the context of comparison with the influence of the base factor only. It is substantiated that, in a crisis, the main motivational element when making decision on the interest rate is managing the risk of customer funds outflow. The author presents the interest rate model and modeling results for the banking system of Ukraine, which are quite close to the real market indicators.