Shares of Whole Foods Market  (WFM) were down over 1% during late morning trading on Thursday after UBS initiated coverage of the stock with a "sell" rating and $25 price target. 

UBS analyst Michael Lasser told CNBC that he believes Whole Foods is struggling to fend off its competitors including Trader Joe's and Sprout's Farmer's Market (SFM - Get Report)

He argued that Whole Foods, for now, is unlikely to return to double-digit sales and earnings growth.