Mirvac, the ASX-listed fund manager, investor and developer, has sold a half stake in a major CBD tower on Sydney’s George Street for $364 million at around a 17 per cent discount to its peak book value, setting a clear benchmark for valuations in the battered office market.

The interest in the 29-storey building at 255 George Street was sold to Singapore’s Keppel REIT for a total consideration of $363.8 million on an investment yield of around 6 per cent. That yield will be a closely watched metric as it allows for comparison, and if need be, adjustment of values across the office market sector.