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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The dollar is strong and things could heat up even further for foreign exchange as global central bankers convene in Jackson Hole.
The Fed is viewed as having too much influence on capital markets and is seen as behind the curve, according to a Wall Street survey.
Names on the move ahead of the open.
Markets are now anticipating a more hawkish tone from the Fed, but maybe not from Yellen when she speaks at the Jackson Hole symposium.
Patti Domm is CNBC Executive Editor, News, responsible for news coverage of the markets and economy.
A CNBC reporter since 1990, Bob Pisani covers Wall Street from the floor of the New York Stock Exchange.
CNBC Senior Commodities Correspondent and Personal Finance Correspondent
JeeYeon Park is a writer for CNBC.com. Follow her on Twitter: @JeeYeonParkCNBC
Rick Santelli joined CNBC Business News as an on-air editor in 1999, reporting live from the floor of the Chicago Board of Trade.
Senior Producer at CNBC's Breaking News Desk.