Millionaire tech titan Dave Greiner and wife Renee have spent $22m to expand their Cronulla beachfront family compound.
The purchase of the neighbouring 1970s Mikeldi duplex adds to their holding by 588 sqm.
Their initial 1175 sqm amalgamation on The Esplanade cost $27.8m after the Sutherland Shire-based couple began their prized beachfront promenade site consolidation in 2018.
They also snapped up two apartment blocks which have been demolished and replaced by a five-storey mansion currently being built by Join Constructions at the southern end of Cronulla Beach.
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Mikeldi, an old block of flats at Cronulla, sits alongside the residential construction site of tech entrepreneur Dave Greiner and his wife, Renee. Picture: realestate.com.au
After initially lodging an $11.5m dual occupancy application, Greiner and wife decided to instead make it one residence.
Greiner is half of the publicity-shy duo from the Shire who built one of Australia’s most exciting technology companies over the past 15 years.
Founded by Greiner and Ben Richardson, Campaign Monitor, now branded Marigold, started out in a garage in the Sutherland Shire.
Making software for email campaigns, it was billed as the “next Atlassian” when it shot to prominence in 2014, selling a $348m stake to US venture capital firms.
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The 1970s duplex adds to the Greiners’ prized beachfront promenade site consolidation begun in 2018. Picture: realestate.com.au
Dave and wife Renee live in Cronulla, and also own a Mollymook Beach weekender where they spent $2m extending the holding, quickly securing approval for a tennis court.
Their Cronulla plans are not yet known, but it would likely involve the relocation of the public pathway between the two properties.
The mystery purchasing company at its Highland Property auction earlier this year was directed by Richardson, but the two shareholders were the Greiners.
Their property play highlights the passion for property compounds by Sydney’s young entrepreneurs.
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Dave and Renee Greine. Picture: Supplied
Richardson built a luxury coastal home at Shearwater Landing, on a 3350 sqm holding, with wife Inger, after consolidating four building blocks that cost $12.6m.
Sydney’s biggest current super-compound project is hillside Vaucluse where White Fox co-founders Georgia and Daniel Contos consolidated four mansions for $124.5m , with construction under way on a $24m estate.
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This article was originally published on 6 Nov 2026 at 9:48am but has been regularly updated to keep the information current.
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