Gulfstream Aerospace has agreed the first letting at 15 Sackville Street, W1, on a 10-year lease.
The US aircraft company has signed for 5,349 sq ft on the fifth floor of the 34,000 sq ft Mayfair building, as tipped by Estates Gazette last week.
It is understood to have paid in excess of £100 per sq ft, and will move to the JM Architects-designed property in March 2013.
Landlord MBK Real Estate Europe secured the letting through its Sackville Street Partnership. CBRE is letting agent on the property and advised Gulfstream.
joanna.bourke@estatesgazette.com
