• Orion to acquire 25% ownership interest in Santo Domingo and Sierra Norte projects for up to $360 million
• Proceeds will reduce Capstone's equity contributions and provide financial flexibility
• Transaction recognizes long-term value of upside and synergy opportunities

Capstone Copper Corp. ('Capstone') announced that fund entities managed by Orion Resource Partners LP ('Orion') have agreed to acquire a 25% ownership interest in the Santo Domingo Project and the Sierra Norte Project for total cash consideration of up to $360 million. The transaction includes a $225 million payment upon a positive final investment decision on Santo Domingo, a $75 million matching contribution within six months of the final investment decision, and up to $60 million in contingent cash consideration. Concurrent with the transaction, Orion will subscribe for $10 million in Capstone common shares. The transaction validates Santo Domingo and Capstone's project execution capabilities, de-risks the capital funding requirements, recognizes the long-term value of upside and synergy opportunities, provides Capstone an option to buy back Orion's 25% stake, and allocates capital to unlock further value at Santo Domingo and Sierra Norte through exploration. The transaction is expected to realize significant value and improve project returns for Santo Domingo, with an expected post-tax IRR of ~24% on an unlevered basis and over 75% on a levered basis. The transaction also benefits local stakeholders and Chile, as Santo Domingo is expected to generate close to 6,000 jobs during construction and over 1,000 jobs once in full operation, as well as over $2 billion in taxes paid in Chile over the life of the mine.

The transaction is expected to reduce Capstone's estimated share of equity contributions for the Santo Domingo project to approximately $400 million, providing financial flexibility during project construction. Capstone is also updating its 2025 consolidated exploration expenditure guidance to $40 million, from $25 million previously provided.

The transaction represents a key milestone toward a construction decision on the Santo Domingo project, expected in H2 2026. Capstone will continue to advance the remaining workstreams, including further advancement of detailed engineering, securing project financing, and ensuring overall balance sheet strength prior to the final investment decision.