Diversified major BHP on Tuesday announced a $4.3-billion silver streaming agreement with Wheaton Precious Metals in what is said to be the most valuable precious metals streaming transaction to date based on upfront consideration received.

Under the long-term agreement, BHP – through a wholly owned subsidiary – will receive an upfront payment of $4.3-billion on completion in exchange for delivering silver to Wheaton calculated by reference to its 33.75% share of production from the Antamina mine in Peru.

BHP holds its interest in Antamina through a 33.75% stake in Compañía Minera Antamina (CMA), which operates the mine independently. CMA is not a party to the agreement, and BHP said its rights as a shareholder and obligations under the joint venture remain unchanged. The stream will also have no impact on BHP’s existing customer agreements.

The transaction allowed BHP to monetise silver, a by-product at Antamina, while retaining full exposure to copper, zinc and lead production from its share of the large-scale, long-life asset. The group said the deal was not expected to increase its reported debt levels.

CEO Mike Henry said the agreement unlocked additional value from the Peruvian operation.

“We are pleased to partner with Wheaton – a global leader in precious metals streaming. BHP’s investment in Antamina has delivered value to investors through strong copper production performance, and this agreement further unlocks additional value from the asset in an innovative and disciplined way,” he said.

CFO Vandita Pant added that the transaction was consistent with BHP’s capital allocation framework and focus on portfolio optimisation.

“Today’s announcement is a further example of our active capital management in action, and focus on strategically unlocking value from our portfolio. The upfront consideration compares favourably with the consensus estimates of our entire share of Antamina. Together with the recent transaction with Global Infrastructure Group and subject to closing of both transactions, we expect to unlock over $6-billion of cash to strengthen our balance sheet flexibility, support long-term value creation and enhance BHP’s shareholder value,” she said.

The agreement has an effective date of April 1, 2026, with completion expected on or around that date. It is not subject to regulatory approvals and remains conditional only on customary closing matters.

Meanwhile, for Vancouver-headquartered Wheaton, the transaction will double its exposure to Antamina’s silver output, lifting its attributable share of silver production from the mine to 67.5%, including its existing stream linked to Glencore’s interest.

President Haytham Hodaly said Antamina had long been a cornerstone asset in the company’s portfolio.

“Wheaton has grown into the company we are today by entering into stream agreements on world-class operations and adding exceptional assets to our portfolio, and Antamina has long stood as one of our true cornerstones,” he said. “Deepening our exposure to an asset of this scale, quality and longevity is a unique and transformative opportunity for Wheaton, made even more meaningful through our collaboration with BHP. Antamina is a proven, long-life, low-cost operation that will deliver immediate production and operating cash flow, and we are confident it will continue to create lasting value for our stakeholders well into the future.”

CEO Randy Smallwood, who was set to assume the role of chairperson at the end of next month, said the deal reinforced Wheaton’s position as one of the world’s largest silver producers.

“Quality silver production is becoming increasingly difficult to source while demand continues to rise for both critical industrial uses and for silver's safe haven qualities in today's economic environment,” he said.

“Our expanded stream on Antamina reinforces Wheaton's role as one of the largest silver producers in the world and further adds to one of the strongest growth profiles in the mining sector. The largest mining company in the world has chosen streaming as a means to unlock value from silver, underscoring how compelling the streaming model has become. We are excited to continue building on this long-standing relationship with the exceptional consortium behind Antamina that shares our commitment to responsible development and long-term value creation.”

Wheaton expects the acquisition to add average attributable silver production of about 6-million ounces a year over the first five years and about 5.4-million ounces a year over the first 10 years. When combined with its existing stream, total attributable production from Antamina is forecast to average about 12-million ounces a year in the first five years.

The $4.3-billion upfront payment will be funded through a combination of existing liquidity and new debt facilities, including a $1.5-billion term loan and a drawdown on Wheaton’s revolving credit facility.

Antamina, located about 270 km north of Lima, is one of the world’s largest copper/zinc mines. In the 2025 calendar year, on a BHP share basis, the operation produced 124 200 t of copper, 129 400 t of zinc and 5.4-million ounces of silver. Other shareholders in CMA are Glencore (33.75%), Teck Resources (22.5%) and Mitsubishi (10%).