Senomyx - Shares surged 28 percent after the FDA designated its sweetener enhancer safe, allowing beverage makers to add it to products to reduce the use of sugar or sugar substitutes.
American Eagle Outfitters - Shares declined 5.2 percent after the teen-apparel retailer forecast earnings for the current quarter below street expectations.
Myriad Genetics - Shares lost 9 percent ground after it said a U.S. District Court in Utah denied a motion to stop rival Ambry Genetics from selling a similar version of Myriad's genetic-susceptibility test for breast cancer.
General Motors - Shares fell 2.4 percent after a Senate aide, who asked not to be identified, told Reuters the Senate Commerce Committee is looking to hold hearings on the auto manufacturer's recalls related to ignition switch problems.
CBS - dropped 0.8 percent after the network's CEO said CBS might offer its content directly to consumers over the Internet and cut its traditional broadcast signal if the Aereo video-streaming service is found to be legal.
EBay - The e-commerce company fell 0.1 percent. CEO John Donahoe's compensation in 2013 fell 53 percent from the prior year, according to a regulatory filing.
Las Vegas Sands - Shares rose 0.3 percent after a strong start in March gaming revenue in Macao. Other casino operators also gained, with Wynn Resorts up 0.9 percent. MGM Resorts International fell 0.7 percent.
Clean Diesel Technologies - Shares jumped 106 percent after the provider of catalysts said it received a Honda Motor Co. vehicle award.
Douglas Dynamics - Shares of rose 2.5 percent after the maker of ice-control equipment for light trucks reported better-than-expected fourth-quarter results.
(Read More: See CNBC's Market Insider Blog)
—By CNBC's Rich Fisherman.
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