Fund manager Quintessential has crystallised a 17 per cent fall in the value of A-grade office buildings in the Brisbane CBD after settling its long-mooted purchase of 240 Queen Street for $250 million.

Flagged in February as a $257 million sale, the 26-storey tower in the city’s Golden Triangle precinct was valued as high as $300 million by vendor Brookfield before rising vacancy rates and higher interest rates sent office valuations tumbling across the country.