Billings at U.S. architecture firms fell faster in September, and the gap between projects people ask about and projects they sign keeps widening. The AIA/Deltek Architecture Billings Index dropped to 44.7 from 47.2 in August, AIA reported Oct. 21. Any score under 50 means more firms saw billings fall than rise.
“This is an increasingly difficult environment for architecture firms,” said Richard Branch, AIA’s chief economist.
Design contracts lag inquiries in the architecture billings data
Project inquiries rose modestly to 53.2. New design contracts came in at 43.7. That 9.5-point spread is the number to watch: owners are still calling architects, but fewer of those calls turn into signed agreements. Architect magazine called it interest that isn’t converting into commitments.
The regional scores, which AIA reports as three-month averages, split the country in half. The West (50.7) and Midwest (50.6) were roughly flat. The South (43.1) and Northeast (39.1) were well into decline.
By sector, commercial and industrial firms were the only group above 50, at 50.9 for a second month of modest growth. Institutional firms posted 47.6, multifamily residential 42.9 and mixed practice 41.5.
Backlogs are shrinking, multifamily fastest
Average backlog was 6.2 months at the end of the third quarter, down from 6.6 months at the end of the first. Multifamily firms took the hardest hit, falling from 6.2 months in March to 4.8 in September, a drop of nearly a quarter. Large firms, those billing $5 million or more, held at 8.1 months, and institutional firms sat at 8.0. Small firms under $250,000 in billings actually rose, from 3.1 to 3.8 months.
Branch said there’s little reason to expect conditions to improve meaningfully in the near term.
What the ABI means for construction starts in 2027
AIA has long pitched the index as a lead indicator for nonresidential construction spending, with design billings turning into construction activity months later. Read that way, September’s data points to a thinner pipeline of drawings reaching bid in 2027, especially in apartments and in the Northeast.
It lines up with what’s already showing up in the field. Apartment starts were down 25.9% from a year earlier in September, and multifamily architects are now losing backlog faster than anyone else. The commercial and industrial reading above 50 fits the data center and industrial work that has been carrying contractor backlogs.
For general contractors, the useful signal is the gap between inquiries and contracts. When it closes, preconstruction work picks up a few months later. Right now it’s widening.