National recognition places brokerage among top Sotheby’s International Realty® firms in the United States Gibson Sotheby’s International Realty has been recognized in the 2026 RealTrends Verified Brokerage Rankings, placing #9 among Sotheby’s International Realty® firms and #62 nationally. The firm was additionally named the #1 Massachusetts-based brokerage by sales volume. These rankings are based on …