Sources said the company took about half of the building’s 18th floor for rents in the $70s per square foot. The deal will add about 12,000 square feet to the roughly 25,000 square feet the firm already occupies at the tower on the floor above, the entirety of 19.

40 West 57th Street

The new lease is being arranged to expire in a little over eight years so that it coincides with the expiration of Tocqueville’s existing space.

Daniel Madison, an executive at Newmark who specializes in leasing space for high end boutique financial tenants, represented Tocqueville in the deal with colleagues John Moran and James Saunders. A CBRE team that includes executives , Howard Fiddle, Zach Freeman and Arkady Smolyansky handles leasing for LeFrak at 40 West 57th Street.

None of the brokers involved in the deal could be reached for comment.

The lease comes as activity and rents have fallen in the Plaza District, an area widely considered the city’s most exclusive office submarkets but that has stagnated as the most active tenants in the market recently, including tech firms, have turned their attention to other areas such as Midtown South.