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.
Lions Gate Entertainment came in 7 cents above estimates with adjusted quarterly profit of 39 cents per share, but revenue fell considerably below analyst forecasts.
BlackBerry will buy back about 2.6 percent of its outstanding shares, to negate potential negative effects of a proposed employee stock purchase plan.
Hewlett-Packard reported adjusted quarterly profit if 87 cents per share, 2 cents above estimates, though revenue was slightly shy of forecasts. The company also issued weaker-than-expected current quarter guidance. Investors are taking note of a positive development—lower-than-expected expenses for the separation of its personal computer and printer businesses into a separate company.
Deere & Co. earned $2.03 per share for its latest quarter, beating estimates of $1.55 despite a slight revenue shortfall. Deere noted a weak global agricultural sector, but said good execution aided its bottom line.
Foot Locker beat estimates by 6 cents with earnings of $1.29 per share. Revenue and same-store sales were above analyst forecasts, and the company said the quarter was the most profitable in its history.
Campbell Soup earned an adjusted 62 cents per share for its latest quarter, 10 cents above estimates, though revenue fell short due to currency effects. Campbell said its full-year sales would fall towards the lower end of its projected range, but earnings would be at the more favorable end.
European equities were mixed on Friday as investors focused on a central bank meeting in Portugal and Yellen's speech.
Mario Draghi, president of the European Central Bank (ECB), spoke at the event in Sintra, Portugal earlier Friday. He said that the economic outlook for the euro zone is looking "brighter today than it has done for seven long years."
The S&P 500 ended mildly higher on Thursday above its previous record close of 2,129.20 to post its 10th closing high for the year.
—Reuters and CNBC's Peter Schacknow contributed to this report.