Security of transactions in Mobile Commerce is moving away from an IT concern to a Business concern because of potential loss of revenue to businesses due to lack of privacy, integrity or confidentiality, system slowdown or downtime. While most of the various security procedures are limited to corporate IT infrastructure, in mobile commerce issues concerned with transaction security appear to have extended beyond the corporate network to embrace the complete business process. Any lapse in procedures that maintain confidentiality of data or violation of privacy could affect corporate image and hence would impact customer relationships. Any adverse effect on customer relationship would negatively impact business revenue. In addition to existing security problems in a wired commerce environment, the emergence of mobile devices has renewed calls for addressing security threats to financial transactions. These problems are discussed in this paper as key issues in terms of organisation's architectural and procedural approaches to security, reliability and availability of business transactionss.