The Leading Economic Index rose for the eighth month out of the past nine. The index was flat in July with the last downturn occurring in March.
The index, which rose 1 percent in November, rose 0.1 percent in December to 99.4.
The index is a comparison to economic conditions in 2004, which have been assigned a value of 100.
"Despite month-to-month volatility in the final quarter of 2013, the U.S. LEI continues to point to gradually strengthening economic conditions through early 2014," said Conference Board economist Ataman Ozyildirim.
"The LEI was lifted by its financial components in December, but consumer expectations for business conditions and residential construction continue to pose risks," Ozyildirim said.
The U.S. coincident index, which measures current business conditions, also rose in December, climbing 0.2 percent to 108.1.