Stocks On the Move: GNC Holdings Inc, AveXis Inc, and Micron Technology, Inc.

U.S. stocks are flat ahead of the holiday weekend. Among specific equities in focus today are health products retailer GNC Holdings Inc (NYSE:GNC), biotech AveXis Inc (NASDAQ:AVXS), and semiconductor stock Micron Technology, Inc. (NASDAQ:MU). Here's a quick look at what's moving GNC, AVXS, and MU.

• GNC is down 11.8% at $10.70 -- currently the worst performer on the New York Stock Exchange (NYSE), and on the short-sale restricted list (SSR) -- after a price-target cut to $7 from $11 from Piper Jaffray, in record-low territory. The analysts warned that fourth-quarter estimates are too high for GNC Holdings Inc, and the elimination of paid memberships puts the firm at risk for an earnings shortfall. GNC shares have stair-stepped lower since mid-2015, with the stock just off an all-time low of $10.29. Near-term option players may be sweating, with GNC Holdings Inc sporting a call-skewed Schaeffer's put/call open interest ratio (SOIR) of 0.32, in the bottom quartile of its annual range.
  
  
• AVXS is trading 6.8% higher at $52.01, after the biotech said it plans to initiate a study of its AVXS-101 medication for spinal muscular atrophy in the first half of 2017.  The Wall Street rookie has more than tripled since its initial public offering in February -- shaking off a scathing analyst note just last week -- though the shares have pulled back since notching an all-time high of $72.72 in November. Short sellers may be getting antsy, with short interest up 172% over the last two reporting periods, now accounting for 20% of AveXis Inc's float. It would take traders a week to cover these bearish bets, at AVXS' average daily volume.

• MU was in the black earlier -- matching yesterday's post-earnings high -- after positive analyst attention from Argus, which hiked its price target to $28 from $22. However, overbought MU has given up its early lead, down 0.2% at $23.14. The shares have been on a tear upwards in recent months, tacking on nearly 150% since the stock's May lows. In the option pits, buyers have been betting on continued upside, with Micron Technology, Inc.'s 50-day call/put volume ratio at the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX) showing more than four calls bought to open for every put over the last 10 weeks -- a reading that sits higher than 82% of all others from the last year.