The Conference Board's Leading Economic Index, a measure of economic developments as an indicator of future trends, increased 0.8 percent last month to 104.4 following a downwardly revised August reading that showed no change.
The index tracks a handful of component indicators, including labor market conditions, housing construction activity, and credit conditions.
According to the Conference Board, most of the index's components have picked up momentum in the last half-year, suggesting moderate expansion in the economy for the remainder of 2014.
Nine of the ten components contributed to the latest increase, led by improvements in the spread between long and short rates. The index's credit component was also a major contributor, adding 0.11 percentage points as banks gradually loosen credit standards.
On the other hand, housing construction contributed little to September's index, adding 0.05 percentage points as permits for new projects proved lackluster for that month.
"Permits could come under some pressure going forward as the NAHB builder's sentiment index fell five points to 54, following four-straight months of gains," Wells Fargo analysts Tim Quinlan and Zachary Griffiths said in a note. "This could simply be a result of the typical buying season coming to an end; however, this was a sizable drop and may be a sign of caution going forward."
"The financial markets are reflecting turmoil and unease, but the data on the leading indicators continue to suggest moderate growth in the short-term," said Ken Goldstein, Economist at The Conference Board. "Meanwhile, the weak advances in the housing market remain a bigger risk to the outlook than short-term financial gyrations."
The Conference Board's other monthly economic indices, which measure lagging and current indicators, also grew in September, though at a more modest rate: The Coincident Economic Index was up 0.4 percent to 110.2, according to the group, while the Lagging Economic Index ticked up 0.1 percent to 125.1.