Wayne Sidwell, executive chairman of Wellcom Group, is behind Point Piper's latest secret sale.
The Fiani family sold their hillside home after having sought around $12 million.
The price paid by the Grange Investments, a company directed by Sidwell, has yet to emerge.
The East Melbourne-based Sidwell founded the printing company in Melbourne in 2000 and remains the largest shareholder. He is set to step down to non-executive chairman.
His son Andrew has returned to Australia having recently been managing director of Wellcom London.
The Michael Suttor-designed residence last traded in 1995 for $2.15 million when sold by Chris Little, who had commissioned the build.
It was sold by Elie and Sonia Fiani.