Apple now deals with 323 carriers world-wide
Um says that the increase in the number of carriers dealing with Apple, comes after two fairly stable years during 2011 and 2012. As Apple increases the number of carriers it deals with, the quantity of iPhone units it sells should increase.
The analyst says that if these new carriers are planning on selling the next iteration of Apple's smartphone, year-over-year sell-in figures should rise. We've already seen the results of adding more carriers, as Apple's international handset sales topped analysts' estimates last quarter.