The effect mechanism of credit constraint on cycle's formation

Purpose – This paper aims to study the formation and amplification mechanism of the financial crisis and business cycle and also discuss the related optimal rules for the central bank and government. Design/methodology/approach – This study is developed basically on a simple financial business cycle model by embedding credit constrains into the DSGE model. Findings – The model in this paper puts forward an explanation for the mechanism of cycles' formation. Using this it finds that: the financial lever in modern economy is the offender of the USA financial crisis, which created the cycles and amplified it into the crisis when the financial lever multiple was increased to much greater levels, and that the traditional policy rule is not good enough for a long running growth process. Research limitations/implications – The findings in this study suggest that to keep the financial lever multiple under a safe level and to reform the policy rule to be good enough for a long run growth process is necessary. Practical implications – According to the model's principle, the paper claims that: the development of the financial and credit markets during recent years has increased the volatility of the economic cycle – excessive credit abuse has become the root cause of the instability of the economy system; the proportion of the mortgage loan and similar financial products in the economy should be controlled strictly; it is necessary to recheck the traditional standpoint of the monetary policy. Rule policy by the Keynesian model exists as a short‐term problem, thus it is not sufficient to study the questions related to technological shocks. Originality/value – The model in this paper explains well the mechanism of cycles and crisis' formation. The findings under the modeling economy give a safe level for financial lever multiples for the first time. The financial business cycle model being used in studying the Chinese economy is a pioneering and exploratory experiment.