Watch Video Now
It's been a reversal of fortunes for banks in 2012: financial stocks lead this year, up 26 percent, after performing the worst of all 10 S&P sectors last year.
All 10 S&P sectors are down more than 1 percent. If losses hold, it will be the first time since Dec. 8, 2011.
The Dow Jones U.S. Home Construction ETF is booking its worst day in nearly four months
Apple's tumble sent its stock to a 52 week low, and suffered the added misfortune of losing its mantle as "world's most valuable company".
More than 93 percent of the S&P 500 are trading above their moving 50-day moving average.
A widespread rally on Wall Street this year, lifted nearly 37 percent of the S&P 500 components to a new 52-week high.
Some stocks that investors had given up for dead are finding new life in the current market rally.
Quantitative Analyst and Editor of "By the Numbers"
Senior Producer of Quantitative & Market Data Services at CNBC
Markets Producer for CNBC
Market Data Analyst at CNBC