New York-based hedge fund manager Castle Hook Partners has landed the penthouse office lease at Related Companies’ upcoming 625 Madison Avenue tower.

According to a memorandum of lease filed in city records Monday, Castle Hook inked a deal for the entire 52nd and 53rd floors of the planned 53-story development. The lease spans 52,000 square feet, according to a subsequent Savills market report.

The asking rent was not disclosed, but there’s no doubt that Castle Hook paid a premium. Related is seeking rents of up to $400 per square foot for the tower’s upper floors, the Wall Street Journal reported in July. The 15-year lease term includes options to renew an additional 10 years.

Castle Hook currently lists its headquarters at BXP’s 767 Fifth Avenue, known as the General Motors Building. It is unknown whether the lease with Related represents a relocation or an expansion for the firm. A spokesperson for Related declined to comment on the deal, and the Castle Hook team did not immediately respond to a request for comment. 

Castle Hook’s deal follows global investment firm General Atlantic’s 152,000-square-foot commitment at 625 Madison Avenue, announced earlier this month. The future anchor tenant is slated to occupy five floors. Private equity firm Veritas Capital also appeared to secure 92,743 square feet at the development, according to Colliers’ August Manhattan office snapshot report.

Ralph Lauren’s Polo Bar is also in talks to relocate to Related’s tower, according to WSJ, signaling the iconic restaurant’s potential relocation from 1 East 55th Street.

Related’s Philippe Visser signed the mid-September deal on behalf of the developer. David Rogers, an executive officer at Castle Hook, signed for the tenant. It is unclear whether outside brokers were involved in the transaction. 

Emily Davis can be reached at edavis@commercialobserver.com. 

Update: This article has been updated to reflect new information on the square footage of Castle Hook’s lease.