The landmark 100 Barbirolli Square in Manchester is reported to be the subject of a £40m joint investment by Oaktree Capital Management and Moorfield.
A new joint venture is said to have been created to buy the 140,000 sq ft office block from Scottish Widows Investment Partnership.
Scottish Widdows bought the property from DB Real Estate in 2006 for £70m. It was put up for sale with an asking price of £60m last year.
The building is 90% let, with accountant Ernst & Young occupying 50,000 sq ft, and law firms Addleshaw Goddard and DLA Piper occupy 65,000 sq ft and 23,000 sq ft respectively.
The property forms part of the Barbirolli Square estate, which includes the Bridgewater Hall.
Oaktree and Moorfield were unavailable for comment.