Stocks closed narrowly mixed after a volatile session marked by a sell-off in commodity prices and fluctuations in the price of the dollar against major currencies.
The Dow Jones Industrial Average edged up only 0.15 points, or 0.001 percent, to close at 12,807.51.
Among Dow components, Pfizer and Chevron fell, while Alcoa and Bank of America rose.
The S&P 500 fell 4.60 points, or 0.34 percent, to close at 1,356.62, while the Nasdaq sank 22.46 points, or 0.8 percent, to close at 2,841.62. The CBOE Volatility Index, widely considered the best gauge of fear in the market,rose to nearly 17.
Among key S&P sectors, energy and materials declined, while telecom advanced.
Commodities were in focus as silver futures tumbled nearly 10 percentat one point amid heavy volume. Silver futures for May delivery ended 7.6 percent lower at $42.58. The CME is raising margin requirements for silver after the market closes Tuesday. Gold also sank, falling more than 1 percent to close at $1,540.
The Dow Jones UBS Commodities Indexfell more than 1 percent.
Oil prices also declined. London Brent crude fell 2.13 percent to close at $122.45, while U.S. light crude fell 2.18 percent to $111.05.
The dollar, meanwhile, which is hovering near a three-year low against a basket of currencies, traded flat after starting the session higher.
Investors may be profit taking after a strong run-up in commodities prices, said Quincy Krosby, market strategist at Prudential Financial.
They are largely moving money into cash until they have a better sense of the market's direction, Krosby added.
"I think investors are watching to see where the dollar is headed, any direction from the (Federal Reserve) post-meeting, and global demand," she said.
Another factor in the markets Tuesday was a 50 basis point rate hike in India, which some investors took as a sign of slowing global growth. U.S. companies have strongly benefited from sales gains overseas, often in emerging markets.