Contractor backlog reached nine months in May

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Backlog for contractors reached 9.1 months in May and experts said the climb was due in part to data center investment across the nation.

The 9.1 score was recorded by by the Associated Builders and Contractors from a member survey taken between May 20 to June 3. It was higher by 0.3 months from April and 0.7 months from May 2025, officials said.

“Backlog rose to a nearly three-hear high in May,” said Anirban Basu, chief economist at ABC, in a statement. “This increase largely reflects the massive data center investments taking place across the nation.”

Basu noted 14% of ABC members were under contract to work on data centers and experienced higher backlog of 11.6 months compared to firms that aren’t with 8.6 months.

“The way this boom is disproportionately benefiting larger contractors helps to explain why contractor confidence slipped in May even as backlog continued to climb,” he added.

Data center projects have been widely credited with keeping the industry afloat at least since July 2025. In Wisconsin, Microsoft, Vantage Data Centers and Meta are building in Mount Pleasant, Port Washington and Beaver Dam respectively.

Backlog increased in every region except the South. However, the South remains the region with the longest backlog of 10.3 months and the largest year-over-year increase in backlog of 0.9 months. In the middle states, backlog grew since last year by 0.7 months, according to ABC.

Readings for sales, profit margins and staffing levels fell in May, the association’s confidence index showed. However, the readings for the three components were above 50, suggesting growth for the next six months.

The American Institute of Architects reported its billing index fell to 48.3 in April, compared to 49.8 in March. This means the share of architecture firms that reported a decline in billing was more than the share the reported an increase.

National architecture firm billings haven’t crossed the 50-point threshold since January 2023, AIA officials said. Officials noted the value of new design contracts was close to returning to growth and three consecutive months of inquiries of new projects in April.