Halstead Property is the biggest luxury residential real estate brokerage firm in New York, ranked #1 in New York and #3 in the U.S. The firm has nearly 1,000 sales and rental agents throughout 18 retail offices in New York, New Jersey and Connecticut. it was founded in 1984 by Clark P. Halstead, previously a founder of Southby's Realty,[1] and Diane M. Ramirez, In 2001, the business was acquired by Brown Harris Stevens, a New York real estate development and management organization., making it the largest real estate brokerage in New York City [2]; the group is now part of the holding company Terra Holdings [3]