Boosted by inventory investments and a narrowing trade deficit, the economy grew more quickly than had been expected in the third quarter, but economists warned the gains could be fleeting.
At an annual rate of 2.8 percent, the pace of growth over July, August and September was the fastest since the third quarter of 2012. It was also well above the 2 percent level economists had estimated the Commerce Department would report Thursday.
Still, some experts warned that the details of the report didn’t paint quite as rosy a picture as the headline number would suggest.
“I was a little surprised by the overall number, which was higher than expected, but most of that is traceable to the gain in inventories,” said Doug Handler, chief United States economist at IHS. “We are still looking at some serious issues in the fourth quarter.”
For example, consumer spending in the third quarter increased by just 1.5 percent, well below the 2.3 percent pace of the first quarter and the slowest advance since the second quarter of 2011.
“There’s no reason to think there will be a takeoff,” said Guy Berger, United States economist at RBS Securities.
Mr. Berger added that when inventories rise quickly, it tends to pull growth forward from future quarters, increasing the chances that the final quarter of 2013 could prove disappointing. The inventory gain added nearly one percentage point to growth in the third quarter and accounted for much of the upside surprise.
Stocks were little changed in early trading.
Indeed, even as Wall Street digested the report for the third quarter, which was delayed by the government shutdown, worries about the fourth quarter were mounting.
Many economists estimate the shutdown, which began on Oct. 1 and lasted until Oct. 17, will reduce growth by between a quarter and half a percentage point in the final three months of the year.
What’s more, reduced government spending continues to weigh on the economy overall, as across-the-board spending cuts imposed by Congress earlier this year begin to bite. In the third quarter, federal spending fell by 1.7 percent, slightly faster than the decline in the second quarter.
One notable area of strength in the third quarter was the housing sector, which has been one of the brightest spots in an otherwise fitful recovery. Residential housing investment rose by 14.6 percent, a slight pickup from the already-robust gains in the first half of the year.
Many experts have worried that housing and home building might cool because of the bump up in interest rates in the late spring and summer that is making mortgages more costly. But five years after leading the economy down, housing is helping keep it afloat.
In addition, while export growth slowed, imports fell by even more, reducing the trade deficit and boosting the economy’s overall performance.
Thursday’s report is the government’s first estimate for the change in gross domestic product in the third quarter, and the two subsequent estimates are likely to be revised considerably as more data becomes available.
That’s what happened in the first quarter of 2013. After an initial reading showing more healthy growth of 2.5 percent, the Commerce Department ultimately revised that down to a lackluster 1.8 percent pace on lower spending by consumers and businesses than first thought.
In the case of the third quarter, economists will be watching closely when the second estimate comes on Dec. 5 for any sharp swings.
In the meantime, the focus now shifts to Friday’s report on unemployment and payroll changes in October, which was delayed by one week because of the shutdown.
Many economists expect the unemployment rate to rise from the 7.2 percent level recorded in September because of the government furloughs, but payroll levels are a wild card since it is not clear just how much an impact the shutdown has had on the private sector.