The AIA's monthly Architecture Billings Index

ended the month of May with a score of 53.1, its highest mark in nearly a year, thanks to the robust multifamily housing market and solid demand for commercial and retail properties. This reading is sharply up from April's mark of 50.6, and is roughly on par with the year-earlier period. The ABI is a leading economic indicator of construction activity in the U.S. reflecting the nine- to 12-month lead time between architecture billings and construction spending nationally and regionally as well as by project type. Any score over 50 represents an increase in billings.

"Business conditions at design firms have hovered around the break-even rate for the better part of this year," AIA chief economist Kermit Baker, Hon. AIA, said in a press release. “Demand levels are solid across the board for all project types at the moment. Of particular note, the recent surge in design activity for institutional projects could be a harbinger of a new round of growth in the broader construction industry in the months ahead.”

Architecture firms surveyed by the AIA reported noticeable growth in project inquiries, with the index jumping to 60.1 in May from 56.9 in April, a five-month high. Meanwhile, design contracts declined modestly to 52.8 in May from 54.3 in April.

Among the U.S. regions—which are reported as a three-month average—the West posted the largest month-over-month gain in billings with a score of 53.8 in May compared to 53.0 in April, its highest mark in nearly three years. The South followed with a 0.6-point gain from April to 53.7 in May, while the Northeast and Midwest experienced modest drops to 51.2 and 49.9, respectively.

Among the sectors tracked by the index, which are also calculated as three-month averages, multifamily residential led for the seventh-straight month with a mark of 53.7 in May—albeit a modest drop from April—followed by the institutional sector at 53.0, up 2.5 points from the previous month. Both commercial/industrial and mixed-practice ended May at a 51.0, a month-over-month dip for the latter and a slight increase for the former.