The top real estate company (self-reported) in the Realtor Magazine's top 100 companies this year was NRT Inc. out of Parsippany, N.J. They closed 392,452 sides, which is twice the next closest company. They have 1000+ companies and around 61,000 salespeople, which is 3 times the amount of the next closest company in both categories.
To make the top 100, a company needed to report 5,135 sides with 300+ salespeople.
Amazing leadership and business philosophies go into creating successful operations like these.