Alcoa files SEC registration for $5.6b South32 alumina, aluminium and bauxite asset deal

Alcoa has moved its proposed acquisition of South32's bauxite, alumina and aluminium interests forward with a US SEC filing, with the transaction carrying an implied enterprise value of up to USD 5.6 billion.

Alcoa Corporation has filed a Form S-4 registration statement with the US Securities and Exchange Commission (SEC) in connection with its proposed acquisition of South32 Limited's interests across the bauxite, alumina and aluminium value chain.

Under the transaction agreed on June 30, 2026, Alcoa will pay South32 USD 3.1 billion in upfront cash and about USD 1.0 billion in Alcoa shares, while also assuming around USD 750 million in net debt and lease liabilities. A further USD 750 million in contingent cash consideration could become payable depending on alumina and aluminium prices through 2030. 

The transaction has an implied enterprise value of up to USD 5.6 billion. Alcoa will also assume related rehabilitation provisions of approximately USD 1.2 billion.

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Alcoa to take interests across five assets 

It will acquire South32's 86 per cent interest in Worsley Alumina in Western Australia, its 100 per cent interest in Hillside Aluminium in South Africa, a 33 per cent interest in the MRN bauxite mine in Brazil, a 36 per cent interest in the Brazil Alumina refinery and a 40 per cent  interest in the Brazil Aluminium smelter.

The MRN transaction remains subject to the exercise of pre-emptive rights held by the mine's partners.

South32's Mozal Aluminium operation in Mozambique is excluded from the deal. The smelter remains on care and maintenance, while South32 continues to consider a potential divestment.

Deal value linked partly to aluminium and alumina prices

The USD 750 million contingent cash component is tied to average alumina and aluminium prices exceeding agreed strike prices across four successive annual periods beginning July 1, 2026.

The structure gives South32 additional potential consideration through 2030 while allowing Alcoa to link part of the purchase price to future commodity market conditions.

Alcoa will also issue 17,008,960 common shares to South32 at completion. Based on shares outstanding as of June 30, those shares would represent about 6 per cent of Alcoa's outstanding stock before South32 distributes them.

At least half of the stock consideration is expected to be distributed to South32 shareholders through an in-specie dividend, subject to the shares being free of applicable resale restrictions. Following that distribution, South32 shareholders would hold at least approximately 3 per cent of Alcoa's outstanding common stock.

South32 may retain and sell the remaining Alcoa shares in an orderly manner or distribute some or all of them through a capital reduction, subject to Australian legal requirements.

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South32 shifts further towards base metals

Graham Kerr, inaugural CEO of South32, mentioned the transaction would “unlock significant value for shareholders” while repositioning the company as an upstream base-metals-focused business with high-margin assets and transformational growth.

South32 CEO Matt Daley said that after completion, approximately 85 per cent of pro-forma EBITDA would come from base and precious metals.

“Under Alcoa’s ownership, the Assets will be part of a global aluminium value chain business,” Daley said, adding that South32 would work with employees, communities, governments and other stakeholders to support the ownership transition.

South32 shareholders still need to approve the deal

The Form S-4, filed on September 1, 2026, is the latest step in the transaction process. The preliminary prospectus remains subject to completion and potential changes.

South32 will seek shareholder approval and intends to put an ordinary resolution on the transaction to its 2026 annual general meeting.

The transaction therefore still has several steps to clear before Alcoa takes control of the assets, which would significantly expand its interests across the bauxite, alumina and aluminium chain.

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