Derwent London has sold 13-17 Fitzroy Street to Arup for £60m.
The deal has exchanged and the price reflects a net initial yield of 7%.
The property is fully let to Arup on a lease expiring 2023 at a rent of £4.46m a year, subject to five-yearly upward only rent reviews.
The sale price represents a decrease of 10% from the 31 December 2008 valuation, which compares to the IPD UK Monthly Property Index for West End & Midtown offices which showed a decline of 14.8% for the first six months of 2009.
The eight storey office building totals 90,420 sq ft and was redeveloped in 2003 as the first of a three phase scheme to provide Arup’s global headquarters.
Following this weeks £60m sale of phase one Derwent London will retain the ownership of phases two and three, which Arup also occupies.
John Burns, chief executive of Derwent London, said: 'The sale forms part of our programme to recycle capital. Arup is an important tenant on our Fitzrovia Estate with whom we have a long standing relationship.
'We are committed to the strategic regeneration of the Fitzrovia area, where our ownership extends to over 1m sq ft and where we look forward to continuing to work closely with Arup.'