Stocks On the Move: NVIDIA Corporation, Ocera Therapeutics Inc, and Flotek Industries Inc

U.S. stocks are slipping after a drop in pending home sales. Among specific equities in focus today are semiconductor stock NVIDIA Corporation (NASDAQ:NVDA), biotech Ocera Therapeutics Inc (NASDAQ:OCRX), and oil-and-gas stock Flotek Industries Inc (NYSE:FTK). Here's a quick look at what's moving NVDA, OCRX, and FTK.

• NVDA is down 6.4% at $109.76, giving up its early gains and retreating from record highs, following a critical tweet from notorious short Citron Research. Specifically, Citron that said the stock will "head back to $90" in 2017 -- which would mark an 18% drop from current levels. The semiconductor stock is now in danger of snapping its 10-session win streak, ahead of its upcoming presentation at next month's Consumer Electronics Show. NVDA has been stair stepping higher for months, up more than 350% since its February low, and is considered one of the best stocks of 2016 -- which may have sparked some end-of-the-year window dressing of late.
  
  
• OCRX is up 8.3% at $2.38, and is among the top performers on the Nasdaq, after H.C. Wainwright started coverage of the biotech with a "buy" rating and $10 price target -- more than four times the current trading price. Earlier, the stock touched $2.95 before backing down from its 80-week moving average -- a trendline OCRX hasn't conquered since February 2014. OCRX is up more than 35% since its late-June low, but has spent the second half of 2016 struggling beneath the $3 area. Most analysts are already in OCRX's corner, though, with all four rating the stock a "strong buy."

• FTK is down 4% at $9.45, after FourWorld Capital Management sent a scathing letter to the oil-and-gas company requesting data to support the purported "miraculous" properties of its fracking additive CNF. This downturn comes during what has historically been a stand-out week for Flotek Industries Inc stock, but the shares are currently down nearly 30% since the beginning of December. FTK short sellers may be cheering, with short interest up 14.1% over the last reporting period. Short interest now represents nearly 30% of FTK's float, which would take 5.9 days to cover, at the stock's average daily volume.