Banking security is an instance of a socio-technical system, where technology and customers’ practices need to work in harmony for the overall system to achieve its intended aims. While the technology of banking security is of interest, our study focuses on exploring the specific practices of household bank customers in the Kingdom of Saudi Arabia (KSA). The findings describe some practices of household customers and reveal some of the reasons behind them. Contrary to banking policy, sharing bank authentication credentials appears to be a common practice for our participants, and a number of different reasons are presented: trust, driving restrictions, the esteem placed in parents, and the ‘need to know’ this information. On the other hand, some participants consider credentials to be private information and do not share, although other participants view this as a sign of distrust. Implications of such practices on the Saudi banking system are outlined and discussed.