Pacific Crest analyst Brad Erickson downgraded Fitbit (FIT) to Underweight from Sector Weight after his channel checks indicated that Charge 2, the company's flagship holiday product, is off to a slow start.

Underweight is Pacific Crest's equivalent of a sell rating. Charge 2 inventory is accumulating in the channel and sell-through is below initial Blaze/Alta levels, Erickson tells investors in a research note.

The analyst continues to believe that a large portion of Fitbit owners will stop using the device within months. Further, he views the corporate wellness deal between Aetna (AET) and Apple (AAPL) as a "substantial negative" for Fitbit. Erickson sees downside to $11 for shares of Fitbit. The stock closed yesterday up 17c to $16.70.