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.

Where prices did climb — warehousing and transportation — points to an inventory build. Upcoming CPI will make the inflation picture clearer.

There are growing concerns about the stickiness of inflation and fears that the Federal Reserve may have to keep interest rates restrictively high for longer.