Wall Street slips at open as investors await Powell's testimony

Wall Street's main indexes opened marginally lower on Tuesday in cautious trading ahead of Federal Reserve Chair Jerome Powell's testimony before Congress that could shed more light on the central bank's interest rate hike plans.

The Dow Jones Industrial Average fell 3.13 points, or 0.01%, at the open to 33,428.31.

The S&P 500 opened lower by 0.16 points at 4,048.26, while the Nasdaq Composite dropped 4.76 points, or 0.04%, to 11,670.98 at the opening bell.