Four of Japan’s largest building groups now own, or are acquiring, some of the best known names in Australian construction. The ownership is the headline. The capabilities travelling with it are what will change how the industry works.
In the space of two years, Japanese companies have agreed to take control of what Sumitomo Forestry calls Australia’s largest detached home builder, a Tier 1 contractor with more than six decades of Australian history, and one of South East Queensland’s biggest developer builders.
Sumitomo Forestry agreed to buy 51 per cent of Metricon in September 2024. Obayashi Corporation agreed in June 2026 to acquire all of Multiplex. Sekisui Chemical announced on 10 September 2026 that it would take 51 per cent of Ausbuild. Kajima has owned Melbourne builder Icon since 2015.
Taken one at a time, each is a company announcement. Taken together, they describe something more useful to understand. These buyers are not financial investors looking for a yield. They are builders and manufacturers, and each brings a specific set of capabilities with it.
Japanese groups now sit across housing, commercial building and development
| Japanese owner | Australian business | Stake | Announced |
|---|---|---|---|
| Sumitomo Forestry | Metricon | 51 per cent, with a pathway to full ownership | September 2024 |
| Kajima | Icon | Parent company | Part of the group since 2015 |
| Obayashi | Multiplex | 100 per cent | June 2026 |
| Sekisui Chemical | Ausbuild | 51 per cent | September 2026 |
| Daiwa House | Rawson Group | 100 per cent | November 2017 |
| Asahi Kasei Homes | McDonald Jones Homes | 80 per cent | April 2021 |
Stakes as announced by the acquiring companies. The Multiplex and Ausbuild transactions had not been confirmed as complete at the time of writing.
Sumitomo Forestry entered the Australian detached housing market in 2008 and bought Henley Properties Group in 2009, followed by Wisdom in New South Wales and Scott Park in Western Australia. It agreed to pay AU$115 million for its Metricon stake, and said the combined group would start more than 7,000 homes a year in Australia. Metricon described the deal as carrying a pathway to full ownership after a number of years.
Kajima established Kajima Australia in 2015, the same year Icon became part of the group. Kajima describes Icon Developments as a developer and financier, and reports more than 1,100 staff across its Oceania business.
Obayashi signed its agreement for Multiplex on 18 June 2026, with the share transfer scheduled for late September. Multiplex reported net sales of about US$3.8 billion in 2025 across Australia, the United Kingdom and Canada.
Sekisui Chemical is buying its stake in Ausbuild through a Brisbane acquisition vehicle, Sekisui Heim Australia AC. The holding companies of Ausbuild’s three joint managing directors keep the remaining 49 per cent, and the transaction has not yet completed.
These follow earlier moves. Daiwa House agreed to buy the Rawson Group in Sydney in November 2017. Asahi Kasei Homes took 40 per cent of McDonald Jones Homes in 2017 and agreed in 2021 to lift that to 80 per cent.
A shrinking home market in Japan is part of the reason
Japan started 740,667 new homes in 2025, according to the Ministry of Land, Infrastructure, Transport and Tourism. That was 6.5 per cent fewer than the year before and the third annual fall in a row.
The companies are open about looking offshore. Obayashi says its strategy is to grow businesses outside Japanese construction until they perform at least as well as its domestic business. It named Australia as one of its most important markets, pointing to population growth, urban development and economic stability.
Sumitomo Forestry framed Metricon as part of building a stable earnings base in its overseas housing business. Australia is one market among several. The same group completed its purchase of United States home builder Tri Pointe Homes in May 2026.
Factory built housing is the capability that travels furthest
The clearest example is Sekisui Chemical. Its housing business has supplied more than 68,000 industrialised homes in Japan under the Sekisui Heim brand, built as factory made modules.
In its Ausbuild announcement, the company said it intends to use modular construction in Ausbuild’s townhouse and terrace business within about three years. It added that it would encourage the establishment of the legal frameworks needed to support that.
Asahi Kasei Homes took a related path. When it lifted its stake in McDonald Jones Homes, it said its industrialised housing know how had helped cut costs by shortening construction time. In April 2020 it bought Australian steel frame manufacturer Steel Building Systems Australia, bringing framing inside the group.
Industrialised housing
Industrialised housing is a system in which most of a home is manufactured in a factory to standardised designs and components, then transported to site and assembled. Volumetric modular construction is one form, where complete three dimensional room modules are fitted out in the factory and craned into position. Panelised construction is another, where flat wall and floor sections are shipped and assembled on site. The shared idea is to move repeatable work off site, where quality and cost can be controlled across volume.
Procurement and supply chains move inside the group
Industrialised systems depend on standardised components and repeatable designs. That changes how materials are bought. A group supplying thousands of homes to a common specification can buy at a scale, and with a forward view of demand, that a single builder rarely has.
For several of these owners, supply is the core business rather than a side line. Sumitomo Forestry’s origins are in forestry and timber, and Metricon described its new parent as having global expertise in wood related industries. Asahi Kasei’s framing acquisition put a structural input under the same ownership as the builder using it.
It is the same logic some Australian builders are now applying at a smaller scale by owning more of their supply chain. The difference is that a Japanese parent can bring an existing manufacturing and procurement operation with it, rather than building one from scratch.
Energy and flood resilience technology are part of the offer
Sekisui Chemical’s plan for Ausbuild goes beyond the building method. The company pointed to rising electricity prices in Australia and strong demand for solar. It said it would draw on its experience with solar power, storage batteries and home energy management systems to spread energy saving homes.
It also said it would apply its drainage and water storage technology to develop residential land that is more resilient to flooding, noting that Queensland experiences frequent river and inland floods.
Patient capital and development capability extend the time horizon
Several of these deals combine land, building and finance. Ausbuild both develops land and builds homes, and Sekisui Chemical said it would use Ausbuild’s development land and existing sales and construction systems as its starting point in Australia.
Kajima has moved into rental housing. In June 2025 it formed a joint venture with Pro‑invest Group to develop purpose built build to rent housing in Australia, starting with an initial AU$500 million commitment.
For Obayashi, the attraction was a builder with an established order book. Its announcement pointed to Multiplex’s substantial backlog of work, including high rise buildings, hospitals and data centres.
None of these are short holds. Kajima has been in Australia for more than a decade and Sumitomo Forestry since 2008. What is changing is not only who owns these builders, but what their owners know how to make.
What is changing is not only who owns these builders, but what their owners know how to make.
What the pattern means for the rest of the industry
For most residential builders, the day to day effect is limited. Brands and management have largely stayed in place. Metricon said it would retain its operating model under Sumitomo Forestry, and Ausbuild’s joint managing directors keep 49 per cent of their business.
The longer term effects sit in three places. The first is competition. A builder working the same growth corridors as a Japanese owned competitor may be pricing against a business with a factory, a procurement network and a parent balance sheet behind it.
The second is trade work. Factory built product moves part of the sequence off site. Site work tends to concentrate on footings, connections, services and finishing, which changes the mix of trades a project needs and when it needs them.
The third is regulation. Australia does not yet have a national certification scheme for prefabricated manufacturers. The Australian Building Codes Board has been tasked with developing one, and Sekisui Chemical’s three year modular target now sits alongside that work as a commercial timeline.
None of this is settled. Deals take time to complete, and a stated plan is not a delivered one. What is already clear is that Australian building now sits inside a wider set of international manufacturing, supply and capital networks, and several of the most significant run through Japan. We will keep tracking how it plays out on site across our coverage of Australian construction industry trends, and on the Good Builder Podcast.
Frequently asked questions
Among the largest are Metricon, in which Sumitomo Forestry agreed to take 51 per cent in 2024; Icon, part of Kajima since 2015; Multiplex, which Obayashi agreed to acquire in full in June 2026; and Ausbuild, in which Sekisui Chemical announced a 51 per cent stake in September 2026. Sumitomo Forestry also owns Henley and holds Wisdom and Scott Park, Daiwa House owns the Rawson Group, and Asahi Kasei Homes agreed in 2021 to take 80 per cent of McDonald Jones Homes.
Japan’s domestic housing market is contracting, with new housing starts falling for a third straight year in 2025 to 740,667. The acquiring companies have described Australia as a stable market with population growth and ongoing urban development, and some have stated goals of growing their overseas businesses to match their domestic operations.
Industrialised housing is a system in which most of a home is manufactured in a factory to standardised designs and components, then transported to site and assembled. It includes volumetric modular construction, where complete room modules are fitted out in a factory, and panelised construction, where flat wall and floor sections are assembled on site. Sekisui Chemical has supplied more than 68,000 industrialised homes in Japan.
Obayashi signed a share transfer agreement on 18 June 2026 to acquire 100 per cent of Multiplex, with the transfer scheduled for late September 2026. Completion had not been publicly confirmed at the time of writing.
Sekisui Chemical has said it intends to use modular construction in Ausbuild’s townhouse and terrace business within about three years, while encouraging the establishment of the relevant legal frameworks. Australia does not yet have a national certification scheme for prefabricated manufacturers, which the Australian Building Codes Board has been tasked with developing.
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Last updated 30 September 2026. Transaction details are as announced by the companies involved and current as at that date.
General Information Only. This article provides general information about ownership and investment in the Australian construction industry. It does not take into account your particular circumstances and is not legal, financial or investment advice. Transaction details are drawn from company announcements and may change as deals complete or are revised. Independent professional advice should be sought before acting on anything in this article.
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