During the September 2008 MicroSave-CGAP workshop in Nepal, various m-banking providers shared the use of a range of communication formats supported on GSM networks, ranging from SMS (Short Messaging Service) through to HTTPS (internet). Each format has a number of advantages and disadvantages over the other potential formats. This note discusses key issues faced when choosing which m-banking format to use. These issues include: usability/reliability, security and ubiquity. The note examines the trade-offs involved and highlights the implications of some of the decisions that must be made on formats.