Take a look at some of Monday's midday movers:
Achillion Pharmaceuticals - The hepatitis C drug developer surged on speculation it could be taken over.
Allergan - Shares of the Botox maker fell after activist investor Bill Ackman, speaking on CNBC, said Allergan shareholders told him they would support a deal at $180 a share. Ackman and Valeant Pharmaceuticals International are in the midst of a hostile takeover of Allergan.
Apple -The iPhone maker gained in its first session after a seven-for-one stock split.
Capital One Financial - The credit card issuer climbed after Nomura upgraded the stock to buy from neutral.
Family Dollar Stores - The discount retailer gained after adopting a one-year poison pill with a trigger of 10 percent, after Carl Icahn reported a 9.4 percent stake in the company, making him its largest shareholder.
Gilead Sciences - The drug developer fell after news that Merck was entering the hepatitis C market with its acquisition of Idenix Pharmaceuticals. Piper Jaffray said Merck could be in stronger position for its patent litigation against Gilead's hepatitis C Sovaldi drug.
McDonald's - The fast-food chain fell after reporting another month of disappointing sales in the United States.
Morgan Stanley - The bank gained on news it is selling its controlling stake in pipeline firm TransMontaigne to NGL Energy Partners for $200 million.
NeuStar - The provider of technology and directory services fell on reports it could lose a phone contract to rival Ericsson, citing an email made public on a government website.
Office Depot - The retailer gained on a positive article in Barron's, which said shares could rise over 50 percent.
Pilgrim's Pride - The poultry producer declined after it lost out to Tyson Foods in its attempt to buy Hillshire Brands.
(Read More: )
—By CNBC's Rich Fisherman.
Questions? Comments? Email us at marketinsider@cnbc.com