The U.S. economy grew at a 2.7 percent annual rate from July through September, much faster than first thought. The strength may fade in the final months of the year if Congress and the Obama administration fail to reach a budget deal.

The Commerce Department said Thursday that growth in the third quarter was significantly better than the 2 percent rate estimated a month ago. And it was more than twice the 1.3 percent rate reported for the April-June quarter.