We introduce a new mobile transaction model applicable to decisionmaking applications over aggregate data warehoused on mobile hosts. The model allows the aggregate data to be updated in disconnection mode, while guaranteeing a very high rate of commitment on reconnection. We name such transactions High Commit Mobile Transactions, or HiCoMo. At reconnectiontime, HiCoMo's are analyzed and several base (fixed network) transactions are generated in order to bring the same effect upon the base tables from which the aggregates are derived. In this paper, we provide a formal definition for the concepts related to HiCoMo's, and a transformation algorithm that is used to analyze them and generate base transactions. We provide a simple example scenario to demonstrate the usefulness of this transaction model. Finally, we compare the commit behavior of HiCoMo's to that of the two-tier model using simulation and a mobile transaction benchmark drawn from an inventory application domain.