Shoppers at an H&M store in New York.

A key economic indicator rose more than expected in December to build on momentum from the previous month.

Leading indicators rose 0.6 percent in December, more than the 0.5 percent expected by economists surveyed by Reuters. The index rose 0.4 percent in November, coming inline with expectations.

"The passing of the tax plan is likely to provide even more tailwind to the current expansion," Conference Board research director Ataman Ozyildirim said in a statement.

Ozyildirim noted that the index's gains were widespread across its indicators.

The Index of Leading Economic Indicators is a closely followed indicator used to forecast global economic trends and take a pulse on the U.S. economy. The Conference Board determines a composite value based on 10 key metrics, including manufacturers' new orders, stock prices and average weekly unemployment claims to create the composite value.