Associated Builders and Contractors reported on October 13 that its Construction Backlog Indicator rose to 8.7 months in September 2026. That is 0.2 months above August’s 8.5 and 0.2 months above September 2025. The indicator measures work under contract but not yet performed, expressed as months of the firm’s prior-year revenue, and comes from a survey of ABC member firms in commercial, industrial and infrastructure construction. ABC ran the September survey from September 21 to October 5. Over the past 12 months the reading has averaged 8.4 months, and September’s figure ties April and June 2025 for fifth-highest of the last 25 months. The top reading in that window is May 2026’s 9.1.
Backlog has climbed back from July's low
ABC Construction Backlog Indicator, months of work under contract, September 2024 to September 2026
| Month | Backlog (months) | Change from prior month (months) | Change from a year earlier (months) |
|---|---|---|---|
| Sep 2025 | 8.5 | 0.0 | -0.1 |
| Oct 2025 | 8.4 | -0.1 | 0.0 |
| Nov 2025 | 8.1 | -0.3 | -0.3 |
| Dec 2025 | 8.2 | 0.1 | -0.1 |
| Jan 2026 | 8.0 | -0.2 | -0.4 |
| Feb 2026 | 8.1 | 0.1 | -0.2 |
| Mar 2026 | 8.6 | 0.5 | 0.1 |
| Apr 2026 | 8.8 | 0.2 | 0.1 |
| May 2026 | 9.1 | 0.3 | 0.7 |
| Jun 2026 | 8.8 | -0.3 | 0.1 |
| Jul 2026 | 8.0 | -0.8 | -0.8 |
| Aug 2026 | 8.5 | 0.5 | 0.0 |
| Sep 2026 | 8.7 | 0.2 | 0.2 |
What moved
Commercial and institutional work drove the gain. That segment rose to 9.0 months from 8.5, the highest since July 2025, according to ABC. In ABC’s definitions the segment covers offices, retail, multifamily, hospitals, schools, warehouses and data centers. Heavy industrial backlog slipped to 8.1 months, its lowest since March, though it is still 0.5 months above a year ago. Infrastructure fell to 9.4 months from 10.0.
| Group | Sep 2025 | Aug 2026 | Sep 2026 | Change from a year earlier (months) |
|---|---|---|---|---|
| Commercial and institutional | 8.5 | 8.5 | 9.0 | 0.5 |
| Heavy industrial | 7.6 | 8.3 | 8.1 | 0.5 |
| Infrastructure | 9.5 | 10.0 | 9.4 | -0.1 |
| Middle States | 8.6 | 7.8 | 6.7 | -1.9 |
| Northeast | 7.6 | 7.8 | 8.5 | 0.9 |
| South | 9.9 | 9.8 | 10.3 | 0.4 |
| West | 7.5 | 8.3 | 8.1 | 0.6 |
| Revenue under $30 million | 7.8 | 7.5 | 7.7 | -0.1 |
| Revenue $30 million to $50 million | 7.8 | 8.9 | 6.4 | -1.4 |
| Revenue $50 million to $100 million | 8.3 | 10.1 | 11.3 | 3.0 |
| Revenue $100 million or more | 12.5 | 11.9 | 11.8 | -0.7 |
The regional numbers moved further than the national one. The South rose to 10.3 months and the Northeast to 8.5. The Middle States, ABC’s 12-state block from Ohio and Michigan west to the Dakotas and Kansas, fell to 6.7 months from 7.8. That is the lowest Middle States reading since September 2023 and 1.9 months below a year earlier.
ABC chief economist Anirban Basu tied the gain to data centers. By his count, the 15% of members under contract on data center work averaged 11.3 months of backlog in September, three months more than members without it. He also said 39% of contractors with more than $100 million in annual revenue have data center work now, compared with 1 in 10 smaller firms. The workbook’s revenue bands do not line up neatly with that split. Firms with $50 million to $100 million in revenue jumped to 11.3 months, while the $100 million-plus group held near 11.8 and sat below its 12.5 of a year ago. The $30 million to $50 million band dropped from 8.9 to 6.4 in one month.
The Construction Confidence Index, a diffusion index from the same survey where readings above 50 mean more firms expect growth than decline, moved in both directions. Staffing rose to 60.7 from 59.5. Sales fell to 60.1 from 62.0, the lowest since November 2025, and profit margins fell to 52.0 from 52.9. Basu said more than 1 in 4 contractors expect margins to shrink over the next six months. In the workbook, 23.7% expected margins to fall a little and 2.6% expected them to fall a lot.
How to use this number
ABC computes the indicator for each firm as current backlog dollars divided by prior fiscal-year revenue, times 12. You can run the same arithmetic on your own books and compare like with like:
- Take contracted backlog from your work-in-progress schedule at the end of September.
- Divide by last fiscal year’s revenue and multiply by 12.
- Compare the result with the row in the segment table closest to your firm: your main market segment, your region, and your revenue band.
A $40 million commercial contractor in Ohio would read three rows: commercial and institutional at 9.0, Middle States at 6.7, and the $30 million to $50 million band at 6.4. The segment row is above the national 8.7, while the region and size rows are at least two months below it. For that firm, the region and size rows are the closer comparison. The site’s post on computing backlog in months walks through the calculation with a worked example.
The second use is sorting out how much of the national number applies to you. Basu puts members with data center work at 11.3 months and members without it about three months lower. If you have no data center contracts, compare your backlog with that lower group before reading the 8.7 as your market. Then check the confidence index, where sales expectations fell for the month, before you plan next year’s bid volume off this year’s.
Revisions and caveats
August’s 8.5 months was not revised. ABC first published 8.5 on September 15, and the October 6 workbook carries the same figure. The workbook replaces the full history each month, so earlier months could change without a mention in the release text.
The indicator is a member survey, and the count of responding firms is not in the release or the methodology note. Subgroups such as a single region or revenue band rest on fewer responses than the national figure, which helps explain one-month swings like the 2.5-month drop in the $30 million to $50 million band. ABC’s methodology note says the backlog figure covers the previous month’s work under contract, based on the latest financials each firm has. ABC revised the reference months for the whole series in May 2020 to better match the survey period. The methodology note does not describe a seasonal adjustment, so part of the July dip and the two gains since could be seasonal. The year-over-year comparison avoids that problem, and on that basis backlog is up 0.2 months.