13 Stocks Moving In Monday's After-Hours Session

Gainers

• Rocky Brands Inc RCKY shares were up nearly 12 percent, reversing a loss of 6 percent in the regular session.
• Mondelez International Inc MDLZ was up 5 percent, after a top and bottom line third-quarter beat.
• EXACT Sciences Corporation EXAS shares were up over 9 percent, after reporting a third-quarter sales beat and raising FY17 sales outlook.
• Cognex Corporation CGNX shares were up 4 percent, after reporting a earnings and sales beat in the third-quarter. The company also raised its quarterly dividend from $0.085 to $0.09 per share.
• Cray Inc. CRAY was up 6 percent after a third-quarter earnings and sales beat.
• Trex Company Inc TREX was up 2 percent , following a third-quarter sales and earnings beat.
• Burlington Stores Inc BURL shares were up 2 percent, after company management raised its third-quarter sales and comps growth outlook.
• Allison Transmission Holdings Inc ALSN was trading up over 5 percent following a third-quarter beat.
• Integrated Device Technology Inc IDTI shares were up 2 percent after reporting a second-quarter earnings and sales beat.

Losers

• Chicago Bridge & Iron Company N.V. CBI shares were down over 3 percent, following a third-quarter earnings and sales miss.
• Texas Roadhouse Inc TXRH shed over 3 percent, after earnings fell in line with estimates despite beating sales estimates. Comps were up 4.5 percent in the quarter.
• Rent-A-Center Inc RCII shares down 3 percent after missing on third-quarter sales and earnings estimates.
• Lombard Medical Inc EVAR shares were down 13 percent after hours.

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).