399 Park Avenue

399 Park Avenue is a 41-story office building that is the world headquarters of Citigroup in New York City, United States.

Citigroup's chairman and chief executive officer operate from the building's second floor. The company moved to the building from 55 Wall Street; a move that marked a migration of several large banks from downtown to midtown Manhattan.

It occupies the entire block between Park Avenue and Lexington Avenue and 53rd Street and 54th Street.

The building lot was assembled by Vincent Astor who initially planned to build a 46-story Astor Plaza on the site. Astor had problems completing the assembly of the lots of mostly residential buildings as a pharmacy held out.

In 1974, the company opened the Citigroup Center annex across Lexington to the east.

In 1987, Citigroup sold one third interest in the building along with two-thirds interest in Citigroup Center to Dai-Ichi Mutual Life Insurance Company for $670 million. At the time, Citigroup said it was moving many of its offices to a new tower in Long Island City in Queens. Citigroup moved out of the top two thirds of the building but kept the lower floors.

Citigroup later bought back its interest in the building.

In 2002, Boston Properties bought the building for $1.06 billion, or $630 square foot, which was the highest price ever paid for an office building at the time. Boston also bought Citigroup Center. Citigroup now leases its headquarters from Boston Properties.