In the last few days, there have been are both upgrades and downgrades to the stock as BlackBerry seeks to win back market share it has lost to the likes of Apple Inc and Samsung Electronicswith new smartphones powered by its BlackBerry 10 operating system.
"The initial enthusiasm that we observed for Blackberry 10 devices now appears to be waning," Ferragu said in a note to clients. He also cut his price target on the company to $10 from $15.
Shares of BlackBerry, which reports fiscal first-quarter results on June 28, fell 3.6 percent to $14.31 in morning Nasdaq trading. The stock dropped as low as $6.22 last September, but has more than doubled in value since then.
The new devices launched over the last few months to mostly positive reviews. But the company has not yet released too many details about sales figures.
Societe Generale analyst Andy Perkins last week upgraded BlackBerry to "buy" from "sell," saying that channel checks had come up with some surprisingly strong numbers for the company's unit sales.
RBC Capital Markets on Monday raised its first-quarter sales estimate to 3.5 million BlackBerry 10 units from 2.75 million. It expects shipments of 4 million BB10-enabled devices in the current quarter, up from a prior outlook of 3 million.