The S&P 500 and the Dow were set for their first back-to-back losses since late-January on Friday, as investors preferred to wait and watch Federal Reserve Chair Janet Yellen's speech for a steer on the chances of an interest rate hike this month.
Yellen could support a rising sentiment among policymakers for an increase in rates amid data pointing to an improving US economy. She is set to speak at 1:00 pm ET (1800 GMT).
Also scheduled to speak is Fed Vice Chairman Stanley Fischer at 12:30 pm ET. Traders have priced in a 75 percent chance of a rate hike when the Fed's policy-setting body meets on March 14-15. The odds stood at roughly 30 percent at the start of the week, according to Thomson Reuters data.
Investors are also assessing their positions following a strong rally on Wednesday, after President Donald Trump's pro-growth speech to Congress and a rise in bank stocks sparked a record day on Wall Street. "I think we are at a position where we have the ability to move up a little bit higher (on rates)," said Paul Springmeyer, investment managing director at the Private Client Reserve at US Bank in Minneapolis, Minnesota.
The S&P 500 is already up 6.3 percent so far this year, compared with the 9.5 percent it gained in 2016, triggering worries over valuation. At 11:02 am ET (1602 GMT), the Dow Jones Industrial Average was down 44.89 points, or 0.21 percent, at 20,958.08, the S&P 500 was down 5.63 points, or 0.23 percent, at 2,376.29 and the Nasdaq Composite was down 14.29 points, or 0.24 percent, at 5,846.93. Nine of the 11 major S&P sectors were lower, with high-dividend yielding utilities and real estate the biggest losers.