An undisclosed occupier is under offer on over 120,000 square foot of offices at One Hanover Street, in what would be the biggest Mayfair leasing deal since December 2023, CoStar News understands.
The occupier is under offer on 124,000 square foot of office space in The Crown Estate’s seven-storey building, according to CBRE UK’s latest Office Market research for Q2 2025. Lease terms were not disclosed.
Global alternative investment manager Ares Management Corporation is the undisclosed party, sources told CoStar news.
Ares appointed CBRE to lead the company’s search for new office space in the West End.
In December 2024, it was reported that Ares was considering a prelet at the Mayfair office development. The site is undergoing extensive refurbishment, with the Orms architects-designed scheme expected to complete by 2026.
Once complete the development will offer refurbished offices, including a new one-storey roof extension and updated retail space.
“This will be one of only four leasing deals over 100,000 square feet in Mayfair this century,” said Mark Stansfield, senior director of UK analytics at CoStar. “All these have been prelets in the past three years, thus emphasising growing demand for modern, large headquarters office buildings in London’s premier submarket,” he added.
“The deal will be the largest leasing in Mayfair since Millennium Management pre-let 173,000 square feet at 50 Berkeley Street in December 2023,” said Patrick Scanlon, senior director of market analytics at CoStar.
The other monster prelets in the West End include McDermott Will & Emery’s June 2025 deal to lease 110,000 square feet of office space 58-63 New Bond Street. The law firm agreed to occupy space on floors four to six of the building at a rent of £182 per square foot.
This followed Blackstone’s July 2022 prelet of 225,000 square feet of office space across floors one to nine of Lansdowne House at 57 Berkeley Square.
The Crown Estate and CBRE declined to comment. Ares declined to comment.