Billings at architecture firms in September increased at their fastest pace since late 2010. As a leading economic indicator of construction activity, the Architecture Billings Index (ABI) reflects the approximate nine to twelve month lag time between architecture billings and construction spending. The American Institute of Architects (AIA) reported the September ABI score was 51.6, up from the mark of 50.2 in August. This score reflects an increase in demand for design services (any score above 50 indicates an increase in billings). The new projects inquiry index was 57.3, compared to a mark of 57.2 the previous month.
Key September ABI highlights:
- Regional averages: West (53.4), South (51.9), Northeast (49.5), Midwest (47.2)
- Sector index breakdown: multi-family residential (57.3), institutional (51.0), commercial / industrial (48.4), mixed practice (47.8)
- Project inquiries index: 57.3
The regional and sector categories are calculated as a 3-month moving average, whereas the index and inquiries are monthly numbers.



The Architecture Billings Index (ABI) saw more poor conditions last month, indicating a drop in design activity at U.S. architecture firms, and suggesting upcoming weakness in spending on nonresidential construction projects. As a leading economic indicator of construction activity, the ABI reflects the approximate nine to twelve month lag time between architecture billings and construction spending. The American Institute of Architects (AIA) reported the June ABI score was 45.9, nearly identical to the mark of 45.8 in May. This score reflects a decrease in demand for design services (any score above 50 indicates an increase in billings). The new projects inquiry index was 54.4, up slightly from mark of 54.0 the previous month.