Midday movers: Hertz, Amazon.com, Twitter & more By: CNBC.com News December 31, 2013 at 12:21 PM EST Take a look at some of Tuesday's midday movers: Read More >> Related Stocks: 3D Systems Corp Amazon.com Apple D.R.Horton Marathon Petroleum Stryker Corp Tesoro Petroleum Co Twitter, Inc. Valero Energy Voxeljet Ag ADR Walgreen Company