Over the last five months, Verizon has slowly been eating away at AT&T's iPhone 4 market share. In January, 100% of all iPhone 4 users were on the then-exclusive AT&T network. Now, that number is 67.7%, according to research firm Localytics.
The iPhone 4 was made available to Verizon on February 10, and by the end of the first week, Verizon customers already accounted for nearly 20% of all iPhone 4 owners.
Since then, that percentage has done nothing but increase. By March, 22.41% of iPhone 4 users were on Verizon, it reaches 25% by April, and as of today, 32.3% of iPhone 4 handsets are running on the Verizon network.
These numbers open up curiosity about how the carriers will split when the next iPhone is released. The iPhone 5, or whatever the next version of Apple's phone will be called, will be the first one to launch of both networks at the same time.
Given how quickly Verizon has managed to eat away at AT&T's dominance in the iPhone market, it wouldn't be surprising to see it account for more than half of the launch-day activations of the iPhone 5.
However, not to be overlooked is that the most loyal iPhone customers have been with AT&T for years and have grown accustomed to the service there, so perhaps that reason alone will keep AT&T as the majority stake-holder in future iPhone devices. Only time will tell.