With two years of construction still ahead, half of the space in One World Trade Center is now leased as a federal agency has signed a 20-year deal to occupy floors 50 through 55 Wednesday.
The U.S. General Services Administration will occupy 270,000 square feet under a lease it signed with the Port Authority.
The publishing company Conde Nast also leased nearly 1.2 million square feet to house its global headquarters, and Vantone China Center leased 190,000 square feet.
"This lease continues the strong momentum we are generating in attracting quality tenants to what will be one of the most prestigious business addresses in the world," Port Authority Chairman David Samson said in a statement.
One World Trade Center, when completed, will be the tallest building in the Western Hemisphere.