Midday Movers: Wal-Mart, Tekmira, Tesla & more

Take a look at some of Monday's midday movers:

Dean Foods moved lower after posting a weaker-than-expected second-quarter loss and issuing a warning on its third quarter. The dairy products firm also pulled its full-year guidance, saying it is facing "by far the most difficult operating environment in the history of the company."

Tekmira continued to advance after the FDA loosened a hold on the pharmaceutical company's Ebola treatment that is in its drug pipeline.

Tata Motors rose after the Indian automobile maker tripled its first-quarter profit, boosted by strong sales of its luxury Jaguar and Land Rover vehicle brands.

Chiquita Brands soared after juice company Cutrale and Brazilian investment firm Safra offered to buy the banana distributor for $610 million, or $13 a share. That proposal could derail Chiquita's merger with Irish rival Fyffes.

Tesla powered forward after Deutsche Bank upgraded the electric car maker to "buy" with a $310 price target, citing better-than-expected growth.

Gogo fell after the in-flight wireless provider said it expects full-year earnings to come in at the low end of its forecast on higher costs.

Twenty-First Century Fox gained ground. CNBC reported hedge fund ValueAct Capital has taken a $1 billion stake in the company.

Mattress Firm climbed after the company said it expects sales to beat street forecasts in the second quarter and full year.

Terex gained ground after a positive article in Barron's said the crane maker could see its stock rise up to 30 percent over the next year because of a pickup in big construction jobs.

ConAgra advanced on official word that the packaged foods company's CEO, GaryRodkin, would retire in May.

Wal-Mart slid after Jefferies downgraded the retail stock to "hold" from "buy" over concerns about investment spending.

Achillion Pharmaceuticals rose after Piper Jafferay upgraded the drug developer to "overweight" from "neutral" and doubled its price target to $10.

Hyatt gained ground after Stifle upgraded the luxury hotel's stock to "buy" from "hold" with a $67 price target, based on valuation.

Transports, including JetBlue, Kansas City Southern, Kirby, Delta, and Alaska Air all moved to the upside, helped by a lower trend in oil prices.

Aramark moved higher on better-than-expected third quarter results. The food services company also raised its full-year earnings outlook.

—By CNBC's Rich Fisherman.