Take a look at some of Tuesday's midday movers:
Allergan - Shares jumped a day after activist investor William Ackman joined Canadian drugmaker Valeant Pharmaceuticals in an effort to acquire the company.
Comcast - Shares of the parent of NBCUniversal and CNBC gained after it reported first-quarter profit that beat expectations.
Facebook - The social media company gained after Credit Suisse upgraded it to "outperform."
General Motors - The auto manufacturer filed a motion in a U.S. bankruptcy court to enforce a ban on suits tied to ignition defects in cars sold before its 2009 bankruptcy. Its shares gained.
Harley-Davidson - The motorcycle maker climbed after tallying a better-than-expected quarterly profit.
Intuitive Surgical - Shares of the medical device company moved higher after it was given regulatory clearance for a version of its da Vinci surgical system.
McDonald's - The fast food chain fell after reporting earnings that declined along with a fall in U.S. same-store sales.
Netflix - Shares of the online film service rose after results showed robust subscriber growth.
Pentair - The provider of water systems slipped after posting first-quarter revenue beneath estimates.
Travelers Cos - The Dow component and insurer gained after reporting first-quarter earnings that topped estimates.
United Technologies - Shares rose after the Dow component hiked the low end of its full-year profit forecast.
Zions Bancorp - The regional bank declined after Evercore Partners downgraded its shares to equalweight from overweight.
—By CNBC's Kate Gibson.
Questions? Comments? Email us at marketinsider@cnbc.com