NRT LLC , the largest residential real estate brokerage company in the United States and a subsidiary of Realogy Holdings , announced the acquisition of Coldwell Banker United, Realtors in Texas, Florida, North Carolina and South Carolina. Coldwell Banker United, Realtors has 60 offices and 2,000 affiliated sales associates, and after the acquisition will continue to operate under the Coldwell Banker brand as Coldwell Banker United, Realtors.