GameStop, Groupon, Nutrisystem are big movers

NEW YORK (AP) -- Stocks that moved substantially or traded heavily Friday on the New York Stock Exchange and the Nasdaq Stock Market:

NYSE

GameStop Corp. up $1.48 at $39.01

An Oppenheimer analyst upgraded shares of the video game retailer, saying that forthcoming video game consoles should boost sales.

Elan Corp. PLC up $1.05 at $13.66

The drugmaker said that it will explore a possible sale of itself after fending off several takeover bids from Royalty Pharma.

Nautilus Inc. down 27 cents at $7.98

The health equipment company said that its chief financial officer has resigned and it has started a search for a replacement.

Nasdaq

American Superconductor Corp. down 30 cents at $2.35

The wind turbine component maker said its fourth-quarter loss narrowed on lower costs, but revenue fell as well.

Casey's General Stores Inc. down $2.60 at $60.69

The convenience store reported a slight uptick in its fiscal fourth-quarter profit despite softer sales and heavy charges.

Smith & Wesson Holding Corp. up 48 cents at $9.78

The gun maker said that strong sales will help the company beat Wall Street expectations for the fourth quarter.

Groupon Inc. up 79 cents at $7.65

A Deutsche Bank analyst upgraded shares of the online deals company, saying that it is likely to grow because of its mobile app.

Nutrisystem Inc. up 65 cents at $10.10

The weight-loss company said that it will start selling its dieting kits in 3,700 Walmart stores.