NEW YORK (AP) -- Stocks that moved substantially or traded heavily Monday on the New York Stock Exchange and the Nasdaq Stock Market:
Penn Virginia Corp., down 29 cents at $3.81
A Stifel Nicolaus analyst downgraded the oil and gas company's stock on its plans to buy assets from Magnum Hunter Resources.
Skechers USA Inc., up 92 cents at $21.51
A Susquehanna Financial Group analyst raised some of the footwear company's earnings estimates citing its market share gains.
Lufkin Industries Inc., up $24.03 at $87.96
General Electric Co. agreed to buy the oilfield equipment maker for $3.1 billion.
Rubicon Technology Inc., up 86 cents at $7.31
A Sterne Agee analyst upgraded the maker of sapphire crystal products to a "Buy," saying industry conditions may improve.
Dot Hill Systems Corp., up 16 cents at $1.50
The data storage company said its first-quarter loss will be smaller than expected and posted a strong second-quarter outlook.
Obagi Medical Products Inc., down $1.44 at $23.98
German drugmaker Merz Pharma Group ended plans to buy the dermatology products maker after a rival raised its offer for Obagi.
BioCryst Pharmaceuticals Inc., up 22 cents at $1.92
Shares of the flu treatment developer rose as concerns continue to grow about a new strain of bird flu emerging in China
AcelRx Pharmaceuticals Inc., up 22 cents at $5.25
A Jefferies & Co. analyst gave the drugmaker's stock a "Buy" rating, saying its pain treatment system may be approved.