©2019 Walter de Gruyter GmbH, Berlin/Boston 2019. The paper analyses from a disequilibrium perspective the role of banks' "animal spirits" and collective behaviour in the creation of credit that, ultimately, determines the credit cycle. In particular, we propose a dynamic model to analyse how the transmission of waves of optimism and pessimism in the supply side of the credit market interacts with the business cycle. We adopt the Weidlich-Haag-Lux approach to model the opinion contagion of bankers. We test different assumptions on banks' behaviour and find that opinion contagion and herding amongst banks play an important role in propagating the credit cycle and destabilizing the real economy. The boom phases trigger banks' optimism that co...