A server comprising: one or more processors, and one or more memories storing instructions, that, when executed by the one or more processors, cause the server, to: for a plurality of users of mobile terminals, cause an analysis on use of each subscriber identity module belonging to a set of subscriber identity modules of a user of a mobile terminal; for the plurality of the users of the mobile terminals, cause a prediction of a future use of the each subscriber identity module belonging to the set on the basis of the analysis; for the plurality of the users of the mobile terminals, cause a selection of at least one optimal subscriber identity module for use by the mobile terminal on the basis of the prediction such that the use of the subscriber identity modules is optimized for the plurality of the users of the mobile terminals simultaneously as regards to the load of the network serving the subscriber identity modules or as regards to the costs of using the subscriber identity modules instead of optimizing the use of the subscriber identity modules for one user only; and for the plurality of the users of the mobile terminals, cause a transmission of the selection of at least one optimal subscriber identity module from among the set of the subscriber identity modules for use by the mobile terminal, the selection informing what at least one subscriber identity module to use. one or more processors, and one or more memories storing instructions, that, when executed by the one or more processors, cause the server, to: for a plurality of users of mobile terminals, cause an analysis on use of each subscriber identity module belonging to a set of subscriber identity modules of a user of a mobile terminal; for the plurality of the users of the mobile terminals, cause a prediction of a future use of the each subscriber identity module belonging to the set on the basis of the analysis; for the plurality of the users of the mobile terminals, cause a selection of at least one optimal subscriber identity module for use by the mobile terminal on the basis of the prediction such that the use of the subscriber identity modules is optimized for the plurality of the users of the mobile terminals simultaneously as regards to the load of the network serving the subscriber identity modules or as regards to the costs of using the subscriber identity modules instead of optimizing the use of the subscriber identity modules for one user only; and for the plurality of the users of the mobile terminals, cause a transmission of the selection of at least one optimal subscriber identity module from among the set of the subscriber identity modules for use by the mobile terminal, the selection informing what at least one subscriber identity module to use. for a plurality of users of mobile terminals, cause an analysis on use of each subscriber identity module belonging to a set of subscriber identity modules of a user of a mobile terminal; for the plurality of the users of the mobile terminals, cause a prediction of a future use of the each subscriber identity module belonging to the set on the basis of the analysis; for the plurality of the users of the mobile terminals, cause a selection of at least one optimal subscriber identity module for use by the mobile terminal on the basis of the prediction such that the use of the subscriber identity modules is optimized for the plurality of the users of the mobile terminals simultaneously as regards to the load of the network serving the subscriber identity modules or as regards to the costs of using the subscriber identity modules instead of optimizing the use of the subscriber identity modules for one user only; and for the plurality of the users of the mobile terminals, cause a transmission of the selection of at least one optimal subscriber identity module from among the set of the subscriber identity modules for use by the mobile terminal, the selection informing what at least one subscriber identity module to use.