Vice Chairman Billy Rose, Chief Executive Mauricio Umansky and President Rainy Hake Austin. What started as a small residential real estate brokerage based in Beverly Hills has grown to more than 800 agents and 50 markets with plans to expand further.  In the 10 years since luxury boutique brokerage The Agency was founded by real estate veterans Mauricio Umansky and Billy Rose, the company has been on a rapid growth trajectory, but Rose and Umansky said it has stayed true to its roots as a boutique brokerage focused on culture and giving its agents and clients a different experience from other brokerages. “I felt that the industry was very archaic and…