Economic output grew at only a 0.7 per cent annual pace in the fourth quarter, to hold overall growth for last year at 2.4 per cent, the same pace as 2014, the Commerce Department reported today.
The year and the quarter were still much stronger than other advanced economies, but the deceleration raised concerns about the underlying strength of US growth as many other countries, including China, struggle to maintain their footing.
Consumer spending slowed somewhat but spending on homes held up in a sign of some tenacity.
It was the second straight quarterly deceleration, and a bit worse than the 0.9 per cent rate that analysts had forecast.
Gross domestic product expansion was 2.0 per cent in the third quarter of 2015 and a brisk 3.9 per cent in the second.
The slowdown came on the back of slumping business investment in buildings and equipment, related in part to the deep contraction in the oil sector.
Imports also fell, helped by the lower cost of imported crude oil, but overall the net trade deficit was a larger drag on GDP growth than in previous months.
Supporting growth was consumer spending on durable goods, which slowed slightly, and services, which was barely changed from the previous quarter.
Also strong was home building and buying, and government spending.
Falling federal government spending has been a persistent drag on economic output for several years; in the fourth quarter a surge in especially defense-related spending made a solid contribution to overall growth.
But analysts were mixed about how to read the strength of the domestic economy after the quarterly data.
In both the quarter and the year, if the net drag on GDP of trade was excluded, the economy appeared to still have sturdy legs.