The new owners are private investors.
Knight Frank’s Langton McHarg and Paul Burns marketed the office with Jones Lang LaSalle’s Robert Anderson and James Kaufman, but all agents declined to comment about a deal.
The building has ridden the wave of several property cycles since it was constructed in 1972.
In 1986, Westpac Property Trust paid $17.7 million for the office, valuing it in 1989, and toward the peak of that property cycle, at $31 million.
When Westpac eventually sold the building, in July 1994, it recovered just $9.75 million.
The Motor Accident Commission of South Australia paid $11.7 million for 356 Collins Street in August 1998, and has held it through two downturns and two upturns including 2001 and 2007.
Elsewhere in the immediate area, the 350 Collins Street office next door sold for $51.5 million last June, while 303 Collins Street nearby also sold in the downturn, for about $56 million.
Last month, Melbourne’s former ASX building at 357 Collins Street across the road – currently an untenanted office – sold to Australand for $45 million.