Because some commercial real estate companies are private, finding information about them can be more difficult.  Many of the resources below are simple lists that provide a starting point and identify major companies in the industry.

Equally, since companies may focus on various aspects of the industry, I recommend looking and searching for companies in those various sub-sectors.  Here are suggestions for searches:

• Real estate and developers
• Real estate and management
• Commercial real estate and construction 
• Builders
• Search on the type of real estate you're interested in, e.g. office space, retail space, healthcare, industrial, multifamily, government, etc.

You can use directories to create lists of companies.  But to do so, you will also need to know about industry classification codes!  Directories often use industry classification codes to identify companies by industry.  The code most likely to be used in North America is called NAICS (North American Industry Classification System). There are other codes out there though.  (There is a link below for far more information about classification codes.) 

Here are some NAICS codes that are relevant to real estate:

• 531120: Lessors of Nonresidential Buildings (except Miniwarehouses)
• 531210: Offices of Real Estate Agents and Brokers
• 236116: New Multifamily Housing Construction (except For-Sale Builders)
• 2362: Non-residential building construction
• 236210: Industrial Building Construction
• 236220: Commercial and Institutional Building Construction

Which directory should you use?

–  For quick look-ups:  use Business Insights Essentials (BIE) or Hoover's Company Records
–  For international scope:  use Business Insights Essentials, Hoover's or Nexis Uni
–  For comprehensive US coverage of both public and private companies: Mergent Intellect (also covers Canadian companies)
–  For creating downloadable lists of companies: Mergent Intellect or Nexis Uni.