By Joann Gonchar, AIA

Just a fraction of U.S. architecture firms are truly large businesses. According to an American Institute of Architects Firms Survey, last conducted in 2003, sole-practitioner offices make up almost one-third of architecture practices. Firms with more than 100 seats make up just 2 percent.

Despite these demographics, RECORD thought its readers would be interested in which firms are the biggest of the big. As we did last year, we have ranked architectural practices on the basis of annual revenue using data gathered by our sister publication, Engineering News-Record, for its own Top 500 Design Firms list.

The chart below is somewhat different from our 2005 list of the largest architect-led firms [RECORD, July 2005, page 78]. Last year's table included only "pure" architecture firms or architecture-prime firms, and we ordered those firms on the basis of total design revenue. Therefore, firms were ranked on the basis of revenue generated not only from architecture, but also from services like engineering, planning, and construction.

By contrast, the 2006 list ranks firms on the basis of revenue derived from architectural services only. However, the table captures many integrated firms with sizable architecture practices. Several of these classify themselves principally as engineering companies.

To participate in the ENR survey, which serves as the basis for this ranking, contact Virgilio Mendoza at (212) 904-6371, or virgilio_mendoza@mcgraw-hill.com.