Apple's annual developer conference in San Francisco.
East Coast Sprint iPhone Inventories are "Seriously Constrained"
"At this time, the majority of East Coast Sprint-branded retail stores are seriously constrained or sold out of iPhone 5 inventory provided to us by Apple," the carrier said. "Our stores will be resupplied as soon as additional devices are received from Apple."
The above image shows an internal Sprint retail order page, with the iPhone 5 out-of-stock in all models at "eligible warehouses" for fulfillment to this particular Sprint location.