Bloomberg cites an unnamed source, who is unauthorized to speak on the matter yet states that the announcement of a Verizon iPhone will occur sometime after the Consumer Electronics Show (CES) in early January. That’s not great news for AT&T since news of a Verizon iPhone ends a monopoly AT&T has had on the device in the U.S. since it was first released in January 2007. Industry analysts believe the defections of subscribers from AT&T to Verizon Wireless, as a result of the CDMA iPhone, could be between 1 million and 6 million.

For 2010, AT&T is expected to sell 15.6 million iPhones. John Hodulik, an analyst at UBS Securities, believes that number will drop to 8.8 milion in 2011. He expects Verizon Wireless on the other hand to sell 13.3 million iPhones in 2011 with 2.3 million of that number coming from former AT&T subscribers.

While AT&T seems to be the focal point of any negative fallout as the result of a Verizon iPhone let’s not forget about Sprint Nextel and T-Mobile who aren’t expected to get the iPhone anytime soon. Hodulik believes that the two carriers will see a drop in subscriber rolls of 650K to 950K as a result.