A key inflation metric eased for the first time since July as investors debate the Federal Reserve's next interest rate decision.

U.S. stock index futures extended gains on Wednesday as investors assessed a broadly in-line consumer inflation report to gauge its effect on the Federal Reserve's monetary policy easing this year. Data from the Labor Department showed the consumer price index rose 2.

Financial writer analyzes December CPI report showing inflation above target, speculates on future trajectory and Federal Reserve policy path. Click for more.

The Labor Department's inflation report for the month of December showed that food and energy prices were the primary drivers of stubborn inflation experienced by consumers.

U.S. producer prices rose less than expected in December as higher costs for goods were partially offset by stable services prices, suggesting inflation remained on a downward trend after progress had stalled in recent months.

Inflation, as measured by the producer price index, rose three-tenths of a percentage point to 3.3% for the year ending in December, hinting that the economy may not yet have vanquished price pressures.