Architecture billings index rose to 47.2 in August as Northeast firms fell to their lowest reading since 2020

Fri, 25 Sep 2026 11:36:24 -0400

The AIA/Deltek Architecture Billings Index (ABI) came in at 47.2 for August 2026, up 0.6 points from 46.6 in July and level with the 47.2 AIA reported for August 2025. The American Institute of Architects published the figure on September 23. The ABI is a diffusion index, a score built from the share of firms that say billings rose versus fell, so 50 means no change and anything below 50 means more firms billed less than the month before. Every month from August 2025 through August 2026 came in below 50, and AIA’s July release called the slump the longest in the index’s history. The latest score sits just above the 12-month average of 46.8 and ties August 2025 for seventh place among the 13 months shown.

Billings stayed below 50 for another month

AIA/Deltek Architecture Billings Index, national score as first reported (50 = no change)

Each month as AIA first published it. AIA later revised December 2025 to 47.1. Source: aia.org

ABI national score, last 13 months, as first reported
Month	ABI score	Change from prior month (points)
Aug 2025	47.2
Sep 2025	43.3	-3.9
Oct 2025	47.6	4.3
Nov 2025	45.3	-2.3
Dec 2025	48.5	3.2
Jan 2026	43.8	-4.7
Feb 2026	49.4	5.6
Mar 2026	49.8	0.4
Apr 2026	48.3	-1.5
May 2026	44.5	-3.8
Jun 2026	47.3	2.8
Jul 2026	46.6	-0.7
Aug 2026	47.2	0.6

Source: aia.org

What moved

The regional split widened. Midwest firms posted 50.7, which AIA describes as modest growth for the first time in nearly a year, and the West was close to flat at 49.8. The South slipped to 46.1 after leading the regions for most of the year. The Northeast fell to 40.7, which AIA says is its lowest level since 2020.

By firm specialization, commercial/industrial rose to 50.4. That is the sector AIA said in its July release had not reported a billings increase since July four years earlier. Multifamily residential eased to 47.8, institutional to 47.0, and mixed-practice firms to 42.5.

ABI detail, July and August 2026
Index	July 2026	August 2026	Change (points)
Midwest	46.7	50.7	4.0
West	47.8	49.8	2.0
South	48.7	46.1	-2.6
Northeast	44.8	40.7	-4.1
Commercial/industrial	46.7	50.4	3.7
Multifamily residential	48.4	47.8	-0.6
Institutional	47.4	47.0	-0.4
Mixed practice	43.2	42.5	-0.7
Project inquiries	52.6	50.8	-1.8
Design contracts	47.2	48.3	1.1

Source: aia.org

The two forward-looking indexes moved in opposite directions. Project inquiries slowed to 50.8 from 52.6, still above 50, so more firms saw new inquiries than saw fewer. The design contracts index, which tracks the value of newly signed design contracts, rose to 48.3 from 47.2 but stayed in decline. Firm leaders have also turned more cautious. AIA says 29% expect billings to decline in the coming quarter, up from 21% at the end of the first quarter, and the share expecting an increase in the fourth quarter fell to 25%.

AIA ties part of the weakness to financing. It notes that the Federal Reserve raised rates by a quarter point at its September meeting, its first increase in three years, and that consumer prices rose 0.4% in August. AIA Chief Economist Richard Branch said, “Architecture firms are caught between stubborn inflation and higher borrowing costs.”

How to use this number

AIA says the ABI leads nonresidential construction activity by about 9 to 12 months. So August’s design billings relate to work that could break ground from roughly mid-2027 onward. If that lead holds, the Midwest and commercial/industrial readings are the first signs in this data of more projects heading toward bid, and the Northeast reading points to fewer projects out to bid there next year. This is a reading of the data, and the AIA releases opened for this post give no regional forecast.

Two uses for a contractor:

If your work is concentrated in one region, track that regional score in place of the national one. Put it next to your own count of preconstruction pursuits or bid invitations by month. A Northeast builder whose pursuit count is holding up while the regional ABI sits at 40.7 is winning a larger share of fewer projects. If the region stays this low, that share has to keep rising just to hold the count steady.
Watch the design contracts index alongside inquiries. Inquiries have been above 50 for most of the year while billings stayed below it, and AIA’s July release says clients keep showing interest while signed design contracts keep falling. Signed contracts are the closer signal of work that will reach bid.

Revisions and caveats

AIA does not label the monthly score as preliminary, but it does revise past months. December 2025 was first published at 48.5, and AIA’s January 2026 release put it at 47.1. The pages opened for this post do not explain that revision, so the chart and table use each month as first reported. That mixes figures from different releases, and the changes in the table carry the same caveat. The January change, for example, is 4.7 points from the first-reported December figure and 3.3 points from the revised one.

The regional and sector scores are three-month moving averages. AIA notes they may not average out to the national score, which is a single month. The national score counts the direction of each firm’s billings and ignores the size of the change. A firm whose billings fell 1% and a firm whose billings fell 30% count the same, so 47.2 tells you more firms billed less without saying by how much.

The index comes from AIA’s monthly Work-on-the-Boards survey of firm owners, principals and partners. The release pages opened for this post do not give the number of responding firms or a margin of error, so a move of under a point in one month (July to August was 0.6) is best read alongside the trend.

AIA | Construction Metrics

Architecture billings index rose to 47.2 in August as Northeast firms fell to their lowest reading since 2020

What moved

How to use this number

Revisions and caveats