Birkenstock billionaire adds $20 million Double Bay penthouse to $160 million Australian property portfolio

German footwear billionaire Alex Birkenstock has continued his extraordinary run of Australian property purchases, acquiring the former Double Bay penthouse of late Perth socialite Eileen Bond for $20 million.

Public records show Birkenstock and his wife, Vanessa, purchased the two-level apartment at 9 Gladswood Gardens, adding another prominent Sydney address to a property portfolio assembled over a relatively short period.

The four-bedroom residence spans around 492 sqm and occupies the upper levels of a tightly held waterfront apartment building overlooking Sydney Harbour.

The property had been the long-time Sydney base of Bond, the former wife of late businessman Alan Bond, who purchased the apartment for $1.225 million in 1986.

Its interiors remained closely associated with Bond, whose distinctive collection of furniture, artwork and colourful finishes gave the residence an identity far removed from the neutral styling commonly seen across Sydney’s prestige apartment market.

The home features multiple living and entertaining spaces, expansive harbour-facing terraces and views extending across Double Bay and the harbour.

Birkenstock reportedly paid around $3 million above the property’s initial $17 million guide to secure the residence, reflecting the scarcity of large-scale waterfront apartments in the eastern suburbs.

Public records show the Double Bay acquisition follows Birkenstock’s purchase of a whole-floor Crown Residences apartment at Barangaroo for $51.5 million earlier in 2026.

That 525 sqm residence occupies the 78th floor of Crown Sydney and was previously owned by the late bookmaker and racing identity Robert Blann.

Birkenstock and his family have also settled on an $85 million Rose Bay waterfront mansion that was Sydney's highest property sale of 2025. The home was bought from James Packer's right-hand man Lawrence Myers, the chief executive of Packer’s family office Consolidated Press Holdings, and his wife, Sylvia. They have almost doubled their money from their $43 million, 2018 purchase, when they bought from retail billionaire Brett Blundy.

David Walker and Peter Janks designed the home on a 1,039 sqm block. It has five bedrooms and a wet-edge pool with spa and canaba.

Birkenstock and his brother Christian built their fortunes through the family-controlled footwear business founded in Germany more than two centuries ago. The brothers sold a controlling stake in Birkenstock to private equity group L Catterton in 2021.

The Double Bay apartment is understood to have been purchased as an investment rather than an immediate renovation project.

Its size, waterfront position and connection to one of Australia’s best-known business families make it a particularly distinctive addition to Birkenstock’s growing local portfolio.

The acquisition also reinforces the depth of international demand at the upper end of Sydney’s residential market, where trophy apartments are increasingly competing with traditional waterfront houses for billionaire buyers.