Take a look at some of Thursday midday movers:
Twitter The microblogging site surged after it opened at $45.10, up 73% from its $26 IPO price. It began trading an hour and 49 minutes after the opening bell.
Tesla Motors fell on news that a third Model S had caught fire, this time in Tennessee.
J.C. Penney Company rose after the retailer reported its first monthly same-store sales gain in nearly two years.
The Men's Wearhouse jumped after CNBC's David Faber reported Eminance Capital had taken a 9.8% stake in the clothing retailer and urged it to solicit bids to sell itself.
Some big-name momentum stocks were taking a hit. Priceline, Amazon, Netflix, Facebook and Baidu were all lower.
Stratasys rose after the 3D-printer maker posted better-than-expected quarterly earnings and revenue.
Apache gained after posting a better-than-expected quarterly profit, helped by record oil production from its wells in West Texas.
Flower Foods fell after the baker's quarterly results didn't rise as much as analysts were expecting.
RDA Microelectronics rose after the chip maker said it received an $18-a-share buyout offer from China's Unigroup.
AMC Networks fell after the cable-TV network's third-quarter profits missed Wall Street estimates.
Siemens hit a five-and-a-half-year high after saying it would repurchase $5.4 billion of its shares.
Visteon fell after the auto-parts maker reported third-quarter earnings barely beat analysts' estimates.
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—By CNBC's Rich Fisherman.
Questions? Comments? Email us at marketinsider@cnbc.com