Thorney Investment Group
Thorney Investment Group is a Melbourne-based family office and activist investor founded by Alex Waislitz in 1991. A generalist across listed and unlisted equities, property, and technology, its water exposure runs through publicly listed environmental-tech holdings. As of 2026, Leviathan tracks 2 water companies across 3 deals and rates its water commitment Occasional.
Compiled by Antoine Walter, (don't) Waste Water, from official filings and direct intelligence in Leviathan.
The take
Thorney Investment Group began in 1991 with a pun and a provocation: Alex Waislitz wanted to be a thorn in the side of complacent company boards that were not delivering value to their shareholders. From that idea grew one of Australia's best-known family offices, an activist investor that takes concentrated, long-term stakes in listed and private companies and pushes for change from the inside.
Thorney is a generalist, not a water fund. It invests across listed and unlisted Australian equities, property, and technology, and it manages two companies listed on the Australian Securities Exchange (ASX), Thorney Opportunities and Thorney Technologies, alongside a large private portfolio. Water is not a strategy here; it arrives through the environmental-technology companies Thorney backs.
Thorney's water exposure sits in two listed environmental-tech holdings. Envirosuite builds software that monitors water, air, and noise, including a digital-twin platform for water and wastewater treatment. Calix develops magnesia-based chemistry that offers a greener alternative to caustic soda in water and wastewater treatment. Both are environment-and-climate plays where treating or measuring water is one feature among several.
Thorney is the kind of investor I file under environmental technology rather than water; it reaches the sector sideways, through listed industrial companies, not a dedicated mandate. Leviathan tracks 2 water companies across 3 deals and rates the firm's water commitment Occasional. Expect any future water bet to look like Envirosuite or Calix: a listed company where water is one feature of a wider environmental story.
Water Commitment Score
Compiled from official filings, third-party records, and direct intelligence from investors and founders, in Leviathan · recomputed monthly · as of Jun 2026.
Portfolio · 2 water companies
Invests alongside
Highlighted = profiled on (don't) Waste Water.
Frequently asked
- What does Thorney Investment Group invest in?
- Thorney Investment Group is a generalist investor, backing listed and unlisted Australian equities, property, and technology rather than a single sector. Its water exposure comes through two ASX-listed environmental-technology holdings, Envirosuite and Calix, whose products help monitor and treat water and wastewater. Leviathan rates its water commitment Occasional.
- Who runs Thorney Investment Group?
- Thorney Investment Group was founded in 1991 by Alex Waislitz, an Australian billionaire who chairs the firm and sets its activist approach. Peter Landos is chief operating officer, and the investment team includes managers such as Avee Waislitz and Margaret Ross, working from the firm's Melbourne base.
- Is Thorney Investment Group a water fund?
- Thorney Investment Group is not a water fund. It is an activist family office that invests across many sectors and takes long-term, concentrated stakes. Water shows up only through environmental-technology companies it backs, such as Envirosuite and Calix. Leviathan tracks 2 water companies across 3 deals and rates the commitment Occasional.
- Where is Thorney Investment Group based?
- Thorney Investment Group is based in Melbourne, Australia, on Collins Street, with affiliations in the United States and Israel. It is the private investment group of Alex Waislitz and manages a wholly owned private portfolio alongside two ASX-listed investment companies it advises from the same Melbourne office.
- What are Thorney Opportunities and Thorney Technologies?
- Thorney Opportunities (ASX:TOP) and Thorney Technologies (ASX:TEK) are two ASX-listed investment companies that Thorney Investment Group manages under a long-term mandate. They are publicly traded vehicles, distinct from the private Thorney family office, which acts as their external investment manager rather than being listed itself.