In a brief period of time, Spanish savings banks (‘cajas’) have changed from being considered a crucial explanatory pillar of Spanish economic development to being seen as synonymous with international systemic risk. This document aims to analyse the circumstances that have brought about this radical change. We will first explore the period between 1997 and 2007, characterised by sustained credit growth and the formation of a real-estate bubble of unprecedented proportions in the Spanish economy. We will then focus on two main aspects related to the banking regulatory framework: the implementation of dynamic provisions by the national bank supervisory authority (Banco de Espana) designed to cope with expected losses rooted in procyclical bank lending behaviour and the role played by the implementation of the Basel II framework with respect to credit risk. This paper detects important deficiencies in the regulatory framework and supervisory process and concludes that these have been one of the main causes of the Spanish savings banks debacle.