Five of the 10 indicators that make up the index were positive factors in December. Consumers' dim outlook for business conditions and weaker expectations for manufacturing orders held back the index.
The index is derived from data that for the most part have already been reported individually.
On Thursday, the Labor Department said weekly applications for unemployment claims continued to trend lower. The fell last week to a seasonally adjusted 330,000, a five-year low.
Home builders started work in 2012 on the most new homes in four years, the Commerce Department said last week.
And stock prices are rising even faster in January than last month. The Standard & Poor's 500 index on Thursday briefly traded above 1,500 on Thursday, the first time that has happened since December 2007.
The Dow Jones industrial average increased 45 points to 13,824 in midday trading. The Dow closed Wednesday at a five-year high.