CEO of Tesla Motors Elon Musk reacts following the company's initial public offering at the NASDAQ market in New York June 29, 2010

Check out the companies making headlines in midday trading.

Tesla — Tesla shares rallied 8.2% after S&P Dow Jones Indices said it would add the electric car maker's stock to the S&P 500 index, effective Dec. 21. This "speaks to the sustained profit trajectory that Tesla is now finally getting into this elusive club after much noise on the Street," said Wedbush analyst Dan Ives.