Trimet asks Brazil's CADE to block Alcoa's $5.6 billion South32 deal, a $900 million synergy bet
Trimet's petition to Brazil's CADE decides whether Alcoa books its $900 million of synergies, loses the assets carrying them, or walks away with $4.1 billion of cash and shares unspent. AA holders are trading the ruling, not the deal.
Richard Tangtwo-minute read
Alcoa's−1.00% — Alcoa, down 1.00 percent today $5.6 billion takeover of South32's aluminium assets now has a regulator standing in the way, and the company that asked is a buyer of alumina, not a seller 1. Trimet, the German smelter group, owns no mines or refineries and buys every tonne of its alumina from third parties, so it competes with Alcoa's customers rather than with Alcoa. It has petitioned Brazil's antitrust authority CADE to block the deal or force asset sales in Brazil or Western Australia 1.
The case is arithmetic, and the price index sits inside it
In Brazil, the transaction would cut smelter-grade alumina suppliers from three to two and leave the merged company with approximately 51.8% of third-party sales, with Alcoa's stake in the Alumar refinery rising to 90% and Worsley returning to Alcoa more than 25 years after regulators made it divest the refinery 12.
Trimet also alleges Alcoa could steer roughly 3 million tonnes of South32's alumina into its own smelters, tightening independent supply 1. The sharper point is the price mechanism: Trimet contracts off the Platts Alumina Index, so a seller holding half the market would be sitting on the benchmark its own costs are set against 2.
Alcoa's South32 deal is mostly cash, with price risk deferred to 2030
- Estimate
Data
| Value | Range | |
|---|---|---|
| Cash | $3.1B | — |
| New Alcoa shares | $1B | — |
| Assumed debt and leases | $0.75B | — |
| Contingent payments (estimate) | $0.75B | $0.00–0.75B |
Three outcomes are live for Alcoa holders
The deal's shape is what moves. South32 shareholders approved the transaction on October 15, 2026, and completion is targeted for June 29, 2027 3. Three outcomes are live. A clean approval delivers the roughly $900 million in net present value of synergies Alcoa expects 3. A block leaves Alcoa holding the $3.1 billion in cash and $1 billion in new shares it raised for the purchase, and frees it from the about $1.2 billion of rehabilitation provisions it would otherwise assume 3.
A remedy that carves out the Brazilian or Worsley assets takes away the integration the synergy case rests on. CADE's Superintendence rules first, and Trimet has asked to join the review precisely so it can appeal any clearance to the tribunal 1.
The asset Alcoa is buying is asserting itself before the sale closes
Worsley workers began a 48-hour strike on November 10 over bonus guarantees and a six-hour gap in weekly hours versus Alcoa's own workforce, and South32 says production will not be affected 34. Unions want the bonuses, worth about 10% of pay on average over five years, written into the enterprise agreement before ownership changes hands 3.
The market is not waiting for certainty either: Alcoa (NYSE: AA) closed November 10 at $39.98, down 4.4% on the day 6. The ruling CADE eventually issues decides whether shareholders get the merged outcome, a carve-out, or no deal at all.
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