text: In mid-2016, the New York City Landmarks Preservation Commission (LPC) proposed protecting twelve buildings in East Midtown, including the Citigroup Center, in advance of proposed changes to the area's zoning. At the time, Boston Properties was contemplating renovations to the building; the company filed alteration plans for the plaza that July, and it was vacating the space in the office annex. On December 6, 2016, the LPC designated the Citigroup Center as a city landmark. The designation made the Citigroup Center the city's youngest landmark at that time. The same month, Boston Properties announced plans to renovate the office annex, which would be rebranded 159 East 53rd Street. Shortly afterward, in March 2017, Gensler revealed its design for a refurbished entry plaza and a new atrium space. That June, work on the plaza commenced; the original fountain, which had been part of the landmark designation, was demolished. All of the space in the 159 East 53rd Street annex was leased to NYU Langone Health in 2018. Following the completion of the renovation, in late 2019, Anna Castellani signed a lease for a  food hall at the base of the Citigroup Center. In October 2019, London-based company etc.venues agreed to operate a  conference center on the 14th floor.
  In 2021, Boston Properties converted the shopping concourse into a food hall named the Hugh. Boston Properties and Norges Bank Investment Management refinanced the Citigroup Center that December with a $1 billion mortgage from four banks. At the time, the building's office space was 96.3 percent occupied, and the tenants largely included financial firms and law offices. With about  of space, the Blackstone Group was one of the building's largest tenants in 2022. Other large tenants by then included Citibank, Kirkland & Ellis, and Freshfields Bruckhaus Deringer.