Take a look at some of Monday's midday movers:
Apple hit a fresh 52-week low.
Radian Group traded at a 52-week high after the company was upgraded to "outperform" from "market perform" at Keefe, Bruyette & Woods with a price target of $12.
Intuitive Surgical added to last week's losses following a report about an investigation into its da Vinci robot. The medical device maker was the worst performer on the Nasdaq 100 index.
Caterpillar was the worst performer on the Dow on concerns about growth in China.
—By CNBC's Lori Spechler
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