Research in Motion shares tumbled more than four-and-a-half per cent on Monday after a UBS analyst downgraded the Blackberry maker's stock to "neutral" from "buy" on price valuation.
Shares ended the day $3.91 lower to $79.70 on the Toronto Stock Exchange, their lowest close since mid-July.
Phillip Huang wrote in a report that the company could face "potential headwinds in the back half of the calendar year," driven by a potential partnership between Verizon Wireless and Apple's iPhone.
AT&T is presently the exclusive authorized carrier of the iPhone in the United States, whereas RIM has agreements with several major U.S. carriers including both AT&T and Verizon.
"Although we don't expect a Verizon iPhone launch this (year or) next year, we believe it could prove to be a sentiment headwind," Huang wrote, while reducing his price target to $88 (U.S.) from $90.
Mr. Huang also noted a possibility that RIM shares could rise if investors react positively to the company's current quarter, which ends later this month.