Shares of Verizon Communications (NYSE: VZ) are dropping despite the company supplanting AT&T (NYSE: T) as the exclusive carrier of the iPhone.

As of 11:20 a.m., VZ shares are down 2.17 percent, while AT &T shares are falling 1.27 percent.

Verizon’s Wireless unit announced this morning that it will introduce the iPhone 4 on its network in early February, thereby finishing AT&T’s four-year tenure of being the phone’s sole carrier.