The Expansion Index for September came in at 1.26, meaning ideated construction investment for the month was 26% higher compared to September 2025.
September’s reading marks 14 straight months of expansion, a streak that began in August of 2025.
Commercial activity, which includes Offices and Data Centers, Parking Garages, and Transportation Terminals, once again led all categories in expansion.
The Expansion Index for September came in at 1.26, meaning ideated construction investment for the month was 26% higher compared to September 2025. September’s reading marks 14 straight months of expansion, a streak that began in August of 2025.
Note: Ideated means any and all projects in some stage of preconstruction. This includes projects whose groundbreaking date may be many years in the future. All such future projects have no guarantee to either achieving a groundbreaking nor reaching to construction completion.
The Expansion Index for September came in at 1.26, meaning ideated construction investment for the month was 26% higher compared to September 2025. September’s reading marks 14 straight months of expansion, a streak that began in August of 2025. Image and Data: ConstructConnect
Commercial activity, which includes Offices and Data Centers, Parking Garages, and Transportation Terminals, once again led all categories in expansion, posting a reading of 2.40.
Eight other verticals also expanded compared to year-ago levels, led by Government, Civil, Community, and Medical, each posting above 30% expansion.
Industrial was the only construction vertical to see a contraction in ideated spending levels, likely due to the high floor of planned industrial activity seen last year.
A chart of the Expansion Index by Subcategory is shown, September 2026. Commercial activity, which includes Offices and Data Centers, Parking Garages, and Transportation Terminals, once again led all categories in expansion, posting a reading of 2.40. Image and Data: ConstructConnect
Expansion reached much of the country, with 48 states and Washington D.C. posting Expansion Index readings above 1.0. Of those, 42 states posted year-over-year gains exceeding 20%, led by Missouri, Montana, and Alaska.
The exceptions were Arizona and Nebraska, both of which saw contractions in ideated spending compared to year-ago levels.
This is in part due to tough year-ago comparisons, particularly in the Industrial space, where a $25 billion chip manufacturing plant contributed to last year's high baseline in Arizona.
Note: High Expansion Index readings reflect growth in ideated investment dollars rather than project count, meaning a single large project can significantly impact a state's index, particularly if the state has a smaller construction market.
September's reading of 1.26 continues the 14-month streak of expansionary readings, with expansion reaching 9 of 10 categories and 48 states and Washington D.C.
That breadth is encouraging for the construction industry, but a gap remains between the strongest and weakest performers. In this environment, finding the right combination of geography and vertical will be key for construction firms to capture future opportunities.
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