Brokerage services for office, retail & industrial properties Business brokerage services for businesses Leasing services for office, retail & industrial properties Property Management services for office, retail & industrial properties If you are buying, selling or leasing commercial property the experienced staff at Sims & Guess Commercial Properties is ready to assist you every step of the way. History Sims & Guess, Realtors is a leading firm in the market place and can trace its beginning back to 1957 with the opening of Sims Real Estate in Odessa, Texas. In 1977, the company became a Century 21 franchisee and changed its name to Century 21 A.G. Sims and Associates. The success and growth of the firm continued through the 1980's under the leadership of Lonnie Sims and his son, Gary Sims.