On a day when AT&T has begun selling the BlackBerry Z10 (BBRY +0.6%), Deutsche's Brian Modoff is raising fresh concerns (previous) about U.K./Canada sales. "Over the past week two carriers in Canada have cut prices on the Z10, suggesting to us lessened demand and possible margin pressure ahead." Modoff says his team contacted 60 stores in its latest round of checks, and failed to find a sellout. Thursday's FQ4 report should provide some color on early sales. (Detwiler Fenton) (Morgan Stanley)