US officials say the country's return to growth is slower than first predicted.
The economy grew at an annual pace of 2.8% between July and September, in contrast to the 3.5% that the Department of Commerce had forecast, the BBC reports.
The change in the Gross Domestic Product (GDP) figure came partly because imports, which count as negative, were higher than first thought.
Imports increased at an annual rate of 21%, the biggest gain since the second quarter of 1985, and a big jump on the 16% initially believed.
However the figures still indicate the first quarterly growth in GDP since the second quarter of 2008.