Take a look at some of Friday's midday movers:
Ambarella - The maker of video-processing chips rose after reporting better-than-expected second-quarter earnings.
BP - The oil producer rose after Citigroup upgraded its shares to a buy from neutral.
Finisar - The network-equipment maker slid after a slew of brokerage firms cut their ratings on the company.
Gap - The clothing retailer fell after posting disappointing same-store sales in August.
Gilead Sciences - The biotechnology company fell after Bloomberg News reported it was nearing a deal with generic drug manufacturers to bring less-expensive versions of its hepatitis C drug to developing nations.
Golar LNG - The shipper fell after its chairman said it would sell up to a 34 percent stake in the company.
Keryx Biopharmaceuticals - The drug developer fell after winning approval from the U.S. Food and Drug Administration for its drug to lower phosphate levels in people with chronic kidney disease.
Priceline Group - The travel site dropped after Evercore downgraded its shares to equal weight.
SanDisk - The data-storage provider rose after Morgan Stanley upgraded its shares to overweight from equal weight.
Starbucks - The coffee-shop operator edged higher after saying it would test an express store in New York next year.
Taser International - The company known for its electric-shock weapons rose on news New York City's police department would begin equipping a small number of its officers with video cameras made by the company.
Tesla Motors - The electric-car maker dropped after CEO Elon Musk described the electronic-car company's stock price as "kind of high right now," at least while viewed in the short term.
Wynn Resorts - The casino operator declined after being downgraded to hold from buy at Argus Research.
—By CNBC's Rich Fisherman.
Questions? Comments? Email us at firstname.lastname@example.org