U.S. stock index futures indicated a flat to slightly lower open for Friday after inflation data and ahead of a speech by U.S. Federal Reserve Chair Janet Yellen.
"Investors are starting to price in ... a rate hike some time in 2015," said Andrew W. Ferraro, wealth advisor at Strategic Wealth Partners. The consumer price index came in "a little higher. That may suggest a slightly earlier rate hike."
The Labor Department said on Friday its Consumer Price Index rose 0.1 percent last month, with the core figure discounting food and energy costs up 0.3 percent, for the largest gain since January 2013.
Economists polled by Reuters had forecast the CPI edging up 0.1 percent from March and dipping 0.1 percent from a year ago.
CPI is important since it is expected that inflation will continue to be low, while the Fed has been looking for signs it will start to pick up.
Futures turned negative on the inflation report and the 2-year Treasury yield gained to 0.61 percent, but longer-end bond yields initially held steady before creeping higher. The dollar pared losses to turn mildly positive.
"I think it wasn't an outstanding number," said TD Ameritrade chief strategist JJ Kinahan. "But when you're at all-time highs and no blow-away numbers it's an excuse to sell."
Trading volumes are expected to be lighter than usual on Friday ahead of the three-day Memorial Day weekend, but all eyes will nonetheless be fixed on Yellen's 1 p.m. ET speech on the economy to the Greater Providence Chamber of Commerce.