• Opportunistic capital raise with net proceeds expected to be used for the development of the Cariboo Gold Project and general corporate purposes
• A portion of net proceeds expected to be used to purchase cash-settled capped calls to offset potential economic dilution by effectively increasing the conversion premium

MONTREAL, May 20, 2026 (GLOBE NEWSWIRE) -- Osisko Development Corp. (NYSE:ODV, TSXV:ODV) ("Osisko Development" or the "Company") announces its intention to offer convertible senior notes due 2031 (the "Notes") in an aggregate principal amount of US$225.0 million in a private placement (the "Offering") to persons reasonably believed to be qualified institutional buyers pursuant to Rule 144A under U.S. Securities Act of 1933, as amended (the "Securities Act").

The Company intends to grant the initial purchasers of the Notes an option to purchase, during a 13-day period beginning on, and including, the date on which the Notes are first issued, up to an additional US$25.0 million aggregate principal amount of Notes. The Offering is subject to market and other conditions, and there can be no assurance as to whether or when the Offering may be completed, or as to the actual size or final terms of the Offering.

Double Zero Capital, LP, an affiliate of the Company (the "Affiliated Investor"), has indicated an interest in purchasing up to US$50.0 million aggregate principal amount of Notes in a separate concurrent private placement under Section 4(a)(2) of the Securities Act (the Notes purchased by the Affiliated Investor, the "Affiliate Notes"). The Affiliate Notes are expected to be sold at the same price, and constitute part of the same series, as the Notes. The Affiliate Investor is under no obligation to purchase any of the Affiliate Notes offered and its interest in purchasing such Affiliate Notes is not a commitment to do so.