Due to overwhelming global demand of Galaxy S4, the initial supply may be limited. We expect to fulfill inventory to meet demands in the coming weeks.
Hopefully Samsung will be able to resolve their short supply issue by mid-May next month, and not end up like the case of Nexus 4. Nevertheless, US Cellular has already confirmed that the Galaxy S4 will be up for sale at their local stores on April 30th next week – so it seems like not all carriers are affected by the limited supply at the moment.
Source : Bloomberg