The work proposes a model of funds formation in current and fixed-term (ruble and currency) accounts and transfers of funds between them. The sources of money are loans issued by commercial banks, placement of government domestic debt, the positive balance of foreign trade. The financial parameters and characteristics of the system are estimated using the Kalman filter. The adequacy of the model is confirmed by simulation modeling. It was found that the rate of creation of rubles in current accounts increased from ≈ 8% per annum in 2015-16 ≈ to 12% in 2017-18 and to 29% in 2019-20. The leakage of foreign currency from accounts (in addition to the official outflow of capital) was ≈ 12, 50, 35 billion dollars per annum during the same periods.