While architecture billings moderated in September, design activity shows signs of remaining sluggish at U.S. architecture firms, according to a new report from the American Institute of Architects (AIA).

The Architecture Billings Index (ABI) score in September is 49.7, which improved from the August score of 47.2. However, any score below 50 indicates a decrease in billings. During September, both the new project inquiries and design contracts scores were positive, posting scores of 59.0 and 54.4 respectively.

“Though still in negative territory, the moderating billings score along with the rebound in design contracts and inquiries serve as a continued note of caution for the industry,” says AIA chief economist Kermit Baker. “Continued weakness in the larger economy still doesn’t bode well for future design services, which will likely see continued volatility in the months ahead.”

Key ABI highlights for September include:

Regional averages: South (52.3); West (51.3); Northeast (46.3); Midwest (45.3)

Sector index breakdown: multi-family residential (53.2); mixed practice (53.0); institutional (48.5); commercial/industrial (45.3)

Project inquiries index: 59.0

Design contracts index: 54.4