Midday movers: Twitter, General Motors, Visa & More By: CNBC.com News April 14, 2014 at 13:04 PM EDT Take a look at some of Monday midday movers: Read More >> Related Stocks: 3D Systems Corp Amtd Idea Group Aspen Insurance Holdings Charles Schwab Citigroup Edwards Lifesciences General Motors Goldman Sachs Group J.M. Smucker Company MasterCard Nabors Industries Pandora Media Inc Piper Jaffray Companies Stratasys Ltd Twitter, Inc. Visa Walgreen Company Xerox Corp Yahoo