OSK stock changed hands in a C$2.16 billion Gold Fields deal
Published on 10/01/2026 at 02:36 | Editorial responsibility: Rafael Müller, Editor-in-Chief AD HOC NEWS
OSK stock changed hands through Gold Fields' C$2.16 billion acquisition of Osisko Mining, completed in October 2024, transferring full control of the Windfall gold project in Quebec. The transaction defines the former Osisko Mining investment case more clearly than any current share-price move.
Gold Fields takes Windfall control
According to Mining.com on September 30, 2026, Gold Fields gained full ownership of Windfall in October 2024 after paying C$300 million for an initial 50 percent stake in May 2023. The acquisition consolidated a project that had previously been split between the two companies.
The value of the transaction stood at C$2.16 billion, while the proposed Windfall mine carries an estimated construction cost of C$2.7 billion, according to The Northern Miner on September 30, 2026. That comparison puts the acquisition value at 80.00 percent of the proposed mine's stated capital cost, using the figures reported by the two companies' coverage.
Windfall work enters a pause
The Northern Miner reported on September 30, 2026, that underground development stopped after the exploration-work permit expired at the end of August. Engineering and tender preparation continue while Gold Fields awaits a recommendation from Quebec's Environmental and Social Impact Review Committee.
The permit issue matters because Windfall remains under environmental review, and changes to the project scope could require a renewed approval process. For former OSK holders, the key corporate event is therefore the completed takeover rather than a new operating update from an independently listed Osisko Mining company.
Former OSK identity
MineralPulse identifies Osisko Mining Inc. under the OSK.TO symbol and TSX listing, with gold as its sector. The later Gold Fields transaction explains why Windfall developments now appear under Gold Fields coverage instead of a standalone Osisko Mining market narrative.
OSK stock after the transaction
OSK stock is represented here by Osisko Mining Inc., ISIN CA69106L1031. The October 2024 C$2.16 billion transaction and the September 30, 2026 Windfall permit update are the central dated reference points for assessing the former listing.
Osisko Mining stock profile
- Company: Osisko Mining Inc.
- ISIN: CA69106L1031
- Ticker: OSK.TO
- Primary exchange: TSX
- Sector: Gold mining
- Acquisition value: C$2.16 billion in October 2024
- Windfall estimated capital cost: C$2.7 billion
