Osisko Development Acquires 6.25M Falco Units At C$0.32 Each For C$2 Million, Increasing Stake To 15.9%

Osisko Development Corp. (NYSE:ODV, TSXV:ODV) ("Osisko Development" or the "Company") reports that, on October 17, 2025, Osisko Development acquired, indirectly through its wholly-owned subsidiary, Barkerville Gold Mines Ltd. ("BGM"), 6,250,000 units of Falco Resources Ltd. ("Falco") (each, a "Unit") at a price of C$0.32 per Unit for an aggregate purchase price of C$2,000,000, in connection with a "bought deal" private placement of 41,005,000 Units completed by Falco (the "Offering"). Each Unit consisted of one common share of Falco (each, a "Common Share") and one-half of one Common Share purchase warrant of Falco (each whole warrant, a "Warrant").

Immediately prior to the Offering, Osisko Development owned or controlled, indirectly through its wholly-owned subsidiary, BGM, an aggregate of 48,675,240 Common Shares and 1,790,000 Warrants (collectively, the "Prior Warrants"), representing approximately (i) 16.0% of the issued and outstanding Common Shares on a basic non-diluted basis, and (ii) 16.5% of the issued and outstanding Common Shares on a partially diluted basis (assuming, for this purpose, only the exercise in full of the Prior Warrants).

As a result of and immediately following completion of the Offering, Osisko Development owned or controlled, indirectly through its wholly-owned subsidiary, BGM, an aggregate of 54,925,240 Common Shares and 4,915,000 Warrants (collectively, the "Current Warrants"), representing approximately (i) 15.9% of the issued and outstanding Common Shares on a basic non-diluted basis, and (ii) 17.1% of the issued and outstanding Common Shares on a partially diluted basis (assuming, for this purpose, only the exercise in full of the Current Warrants).