The authors formalize a model of the impact of public incomes on the stability of the banking system in terms of issuing and returning mortgage loans. The possibility of building such a model depending on the number of potential borrowers, terms, loan rates and their average size on panel data 2009-2019 in Russia was investigated. It was revealed that the growth of the average monthly size of incomes of the population significantly lags the growth of monthly lending volumes and loan payments. It was determined that the largest reverse impact on the stability of the banking system is the number of mortgage loans issued. A study of the parameter interaction model showed that the mismatch in the rhythm of issuing and paying off mortgage loans does not contribute to the stability of the banking system, which is aggravated by the stagnation of the number of potential borrowers. Multicollinearity was revealed in combinations of average per capita income, the number of potential borrowers and the key rate of the Central Bank, which indirectly prove the presence of a complex and unobvious complex of interaction between them. The novelty of the author's approach consists in combining the parameters of the model and expanding the idea of the mechanism of mortgage lending depending on the income of the population. Further development of the study of the proposed model is seen in its broadcast to the level of regions of Russia, where there are significant differences in the level of incomes of the population and its ability to be included in the mortgage credit process.