16 Stocks Moving In Wednesday's After-Hours Session

Gainers

• Shake Shack Inc SHAK spiked about 5 percent to $38.92 in the after-hours session following a Q3 earnings beat.
• L Brands Inc LB was up more than 9 percent to $47.80 after reporting encouraging October sale data.
• FleetCor Technologies, Inc. FLT was up about 4.5 percent to $171.75 following an earnings beat and announcing it increased its buyback by $350 million.
• Transocean LTD RIG rose about 2.6 percent to $10.76 after beating earnings estimates.
• QUALCOMM, Inc. QCOM rose more than 1 percent to $54 following an upbeat earnings report.
• Facebook Inc FB was up less than a percent at $183 after a blow-out Q3 earnings report.

Losers

• IMPINJ Inc PI shares were down 19 percent to $26 after Q3 earnings. The company's Q4 guidance fell way below estimates.
• FireEye Inc FEYE plummeted 13 percent to $14.15 after Q4 guidance missed estimates.
• Oclaro Inc OCLR fell more than 13 percent to $6.90 despite a Q1 earnings beat.
• GoPro Inc GPRO fell nearly 10 percent to $9.56 after issuing lower guidance.
• Symantec Corporation SYMC fell 8 percent to $29.50 after issuing lower guidance.
• Hanesbrands Inc. HBI dropped nearly 6 percent to $20.75 despite an inline earnings report.
• Yelp Inc YELP shares were down about 5 percent to $43.20 following lower sales guidance.
• Tesla Inc TSLA fell 4 percent to $307.21 after reporting a wider than expected Q3 loss.
• Kraft Heinz Co KHC dropped as much as 8 percent, but recovered to around $76.25 following Q3 earnings.
• Fitbit Inc FIT was lower by less than 1 percent to $6.24 after Q4 guidance was lower than expected.

After-hours price action occurs in an environment where fewer traders are participating in price discovery. Amid this lack of activity and liquidity in certain stocks, experienced traders will sometimes attempt to manipulate sentiment by placing an order at a price markedly different than a stock's closing price or last price.

It's conceivable less savvy investors could see this price action, assume the sharply higher or lower indication is a signal of news, buy or sell the stock, and ask questions later. This is one reason after-hours price action can sometimes evaporate by the next day's morning trading session (i.e. there is no news -- just trading activity).