John Paczkowski, On Wednesday November 17, 2010, 1:56 pm EST

The iPhone’s debut on Verizon next year will clearly cause some suffering over at AT&T, which is losing its long-running exclusive on the device. but there are a few other companies that will feel the pain of that transition as well: HTC, Motorola and Research in Motion. Verizon is an important distribution channel for all three and the eagerly anticipated debut of the iPhone on its network will likely affect them — but not as much as you’d think.

“We see 3 immediate effects of expansion of the distribution of the iPhone at Verizon,” Bernstein Research analyst Pierre Ferragu said in a note to clients today. “A) Migration of existing iPhone users from AT&T to Verizon; B) some migration of Android users at Verizon to the new iPhone; C) more support to Android from AT&T, as a consequence of the loss of the iPhone exclusivity.”

Worse case scenario, Ferragu figures Motorola, HTC and RIM will lose 10-30 percent of their business at Verizon. but that loss will likely be offset by new gains at AT&T — at least for Android vendors like HTC and Motorola, for whome Ferragu predicts at 0-30 percent increase in shipments at the carrier. Says Ferragu, “If Verizon starts selling the iPhone, we believe there will not be a visible impact for HTC and a limited one for RIM. If there is a medium term impact on Motorola, we believe that the shortfall will be easily made up in the full year.”