Colliers International Group Inc. is a Canada-based diversified professional services and investment management company with approximately 18,000 employees in more than 400 offices in 65 countries.

[10] In 2006, FirstService purchased a majority stake in PGP Valuation and merged with the appraisal arm of Colliers Macaulay Nicolls.

[20][21] The following month, Adena Commercial, a real estate firm in Columbus, Ohio, and Grubb & Ellis Paramount Commerce in Grand Rapids, Michigan, began working with Colliers International.

[28] In October 2017, Colliers acquired Serten Advisors, LLC; a tenant representation firm headquartered in the Washington, D.C., area.

[31] In July 2020, Colliers acquired Maser Consulting P.A., a multi-discipline engineering design services firm based in New Jersey.

[34] Colliers is a full service real estate brokerage firm that operates in 67 countries and is traded on the NASDAQ stock market exchange under the symbol CIGI.

[35] In March 2010, the annual Lipsey Survey of the top 25 brands in the commercial real estate industry worldwide ranked Colliers in second.