US Architecture Billings Stay Weak in August 2026, Multifamily Index at 47.8

The AIA and Deltek Architecture Billings Index came in at 47.2 in August 2026. Multifamily residential work scored 47.8, and the Northeast fell to 40.7.

The AIA and Deltek Architecture Billings Index scored 47.2 in August 2026, the American Institute of Architects reported on 23 September. On this index a reading of 50 means billings were unchanged from the previous month and anything above 50 means they grew, so 47.2 describes a month in which design work at American architecture practices shrank again. July stood at 46.6, so August was marginally less bad rather than a turn.

For property investors the index is worth watching because it sits ahead of the construction cycle rather than inside it. Architects are paid to draw buildings before anyone pours concrete, so a soft billings reading today is a statement about the supply of new space nine to twelve months out.

Multifamily housing is the weakest large residential signal

By sector, on a three-month moving average, commercial and industrial work was the only category above water at 50.4. Multifamily residential came in at 47.8, institutional at 47.0 and mixed practice at 42.5. The multifamily figure is the one that speaks directly to rental housing supply: apartment blocks that are not being designed now are not competing for tenants in 2027 or 2028.

The forward-looking parts of the survey were mixed. Newly signed design contracts scored 48.3, which the institute described as a continued decline, while project inquiries reached 50.8, showing only modest growth. Firms are still being asked to quote; fewer of those conversations are turning into signed work.

The regional spread is unusually wide

Regional scores, also three-month moving averages, ranged from 40.7 to 50.7. Northeast firms at 40.7 reached their lowest level since 2020. The South scored 46.1 and the West 49.8, effectively flat. Only the Midwest, at 50.7, recorded growth.

That is close to a ten-point spread between the strongest and weakest region, and it maps onto the pattern visible elsewhere in American housing data this year, where the coastal markets have cooled hardest.

Rates are named as the pressure point

Richard Branch, chief economist at the American Institute of Architects, put the cause plainly: "Architecture firms are caught between stubborn inflation and higher borrowing costs. The Federal Reserve's latest rate increase may help ease inflationary pressures over time, but in the near term it adds another headwind for projects already facing a difficult financing environment." The release notes that the Federal Reserve raised interest rates by a quarter point at its September meeting. Permitting delays are also cited as stalling projects.

How this sits next to the market itself

Our United States row, in the 22 September 2026 snapshot, carries a national asking price of 2,411 USD per square metre, drawn from a median listing price of 224 USD per square foot for August 2026. On the per-unit pair we hold a typical home value of 369,678 USD against a typical asking rent of 1,948 USD a month, which implies a gross yield of about 6.3%. The twelve-month price trend is 2.2%, our bubble-risk reading is 57 out of 100 in the moderate band, and transaction costs are 6.9% of the purchase price, low by international standards.

Those two pictures are consistent rather than contradictory. Existing homes are still gaining value slowly while the pipeline for new ones thins. For a landlord, weak design activity in multifamily is the more useful half of the signal: it points to less competing supply later, which supports rents, at the cost of fewer new units to buy into. Federal tax treatment matters here too, since a non-resident owner who elects to be taxed on a net basis faces an effective burden closer to 10.7% than the 30% gross withholding that applies by default.

One caution on reading the numbers: the headline 47.2, the contracts score of 48.3 and the inquiries score of 50.8 are monthly, while every regional and sector figure above is a three-month moving average. They are not directly comparable month to month.

Sources: American Institute of Architects, AIA and Deltek Architecture Billings Index, August 2026, published 23 September 2026 https://www.aia.org/resource-center/abi-august-2026-architecture-firm-billings-continue-decline; American Institute of Architects, press release on the August 2026 Architecture Billings Index, 23 September 2026 https://www.aia.org/about-aia/press/architecture-firms-continue-face-soft-business-conditions-0

Market data: Miami (metro area) · United States · Las Vegas (metro area) · New York (metro area)