A lending boom is re?ected in the composition of bank liabilities when traditional retail deposits (core liabilities) cannot keep pace with asset growth and banks turn to other funding sources (non-core liabil- ities) to ?nance their lending. We formulate a model of credit supply as the ?ip side of a credit risk model where a large stock of non-core liabilities serves as an indicator of the erosion of risk premiums and hence of vulnerability to a crisis. We ?nd supporting empirical evi- dence in a panel probit study of emerging and developing economies.