The purchase was agreed in spring last year but was only revealed on public records when it settled in recent weeks.
A source with knowledge of the deal but not authorised to speak publicly pointed to Marshall White’s Marcus Chiminello as the agent,but Mr Chiminello declined to comment.
Sam Hupert is chief executive of medical imaging company Pro Medicus and is valued at $1.32 billion on the AFR Rich List. Both properties are owned in Jacky’s name.
Their main residence is set on an expansive near-2200-square-metre block and was purchased in 2004 for $3 million,records show.
The new addition will extend their compound by another 850 square metres,and has set a new benchmark for land prices in the exclusive suburb of nearly $16,500 per square metre.
Buying the house next door has been a popular strategy for other home owners nearby,allowing for extra space,perhaps more garden or to prevent someone else building a large construction next door.