To be included, a firm must qualify as a real estate GP (General Partner) in the U.S., Canada, or U.K. — meaning it invests its own capital or investor capital (via a GP/LP structure) to buy or build real estate as its primary business.
Not included:
General contractors who do not invest in their own projects
LPs or investment firms with no active development role
Architects, brokers, and consultants
Part-time or one-person firms (e.g., house flippers)