Osisko Development Secures US$450 Million Financing Facility To Develop The Cariboo Gold Project

The Credit Facility provides strategic capital and enhanced financial flexibility as the Company advances Cariboo through the next phase of pre-construction and early works milestones toward construction readiness. It is structured in two tranches aligned with the Project’s planned development timeline. An initial draw of US$100 million (the "Initial Draw") was completed and will be used to: (i) undertake a 13,000-meter infill drill campaign to further de-risk Project mine planning assumptions; (ii) fund pre-construction and construction activities for the development of Cariboo; (iii) repay the Company’s existing outstanding US$25 million term loan with National Bank of Canada, maturing in October 2025; and (iv) support the Project’s general working capital requirements.

"We are delighted to welcome Appian as a new cornerstone investor, which is a significant endorsement of the Cariboo Gold Project and a major milestone in advancing it towards a construction decision," commented Sean Roosen, Chairman and CEO. "Having recently completed an updated feasibility study for the Project, the US$450 million facility represents a key financing commitment and allows us to maintain momentum towards a formal investment decision. The facility is structured to provide us with financial flexibility as we continue to push forward on pre-construction and construction activities and seek to fully fund the Project for construction. Appian is the leading investor in the mining space and has a successful track record of identifying and supporting the development of high-quality assets into production—we are encouraged by their confidence in our team and vision to develop the next major Canadian gold mine."

Michael W. Scherb, Founder and CEO of Appian, commented, "The Cariboo Gold Project perfectly aligns with Appian’s disciplined, technically driven investment strategy. It is situated in a stable jurisdiction, boasts a robust existing minerals base with clear upside potential, and is being led by an experienced management team. The project also holds permits that will enable near-term progress to production. This transaction showcases the strength of Appian’s dedicated credit and royalties offering, including the added value that our market-leading technical team can provide project owners. We look forward to working constructively with the Osisko team to help advance the project."

About Appian Capital Advisory Limited

Appian Capital Advisory Limited is the investment advisor to long-term value-focused private capital funds that invest in companies in metals, mining, and adjacent industries. Appian is a leading investment advisor with global experience across South America, North America, Australia and Africa and a successful track record of supporting companies in metals, mining, and adjacent industries to achieve their development targets, with a global operating portfolio overseeing approximately 5,000 employees. Appian has a global team of 88 investment professionals, combining financial and technical expertise, with presences in London, Abu Dhabi, New York, Dubai, Belo Horizonte, São Paulo, Beijing, Hong Kong, Toronto, Lima and Perth. For more information, please visit www.appiancapitaladvisory.com.

ABOUT OSISKO DEVELOPMENT CORP.

Osisko Development Corp. is a continental North American gold development company focused on past-producing mining camps located in mining friendly jurisdictions with district scale potential. The Company’s objective is to become an intermediate gold producer by advancing its flagship permitted 100%-owned Cariboo Gold Project, located in central B.C., Canada. Its project pipeline is complemented by the Tintic Project in the historic East Tintic mining district in Utah, U.S.A., and the San Antonio Gold Project in Sonora, Mexico—brownfield properties with significant exploration potential, extensive historical mining data, access to existing infrastructure and skilled labour. The Company’s strategy is to develop attractive, long-life, socially and environmentally responsible mining assets, while minimizing exposure to development risk and growing mineral resources.

CAUTION REGARDING FORWARD LOOKING STATEMENTS

Certain statements contained in this news release may be deemed "forward-looking statements" within the meaning of the United States Private Securities Litigation Reform Act of 1995 and "forward-looking information" within the meaning of applicable Canadian securities legislation (together, "forward-looking statements"). These forward-looking statements, by their nature, require Osisko Development to make certain assumptions and necessarily involve known and unknown risks and uncertainties that could cause actual results to differ materially from those expressed or implied in these forward-looking statements. Forward-looking statements are not guarantees of performance. Words such as "may", "will", "would", "could", "expect", "believe", "plan", "anticipate", "intend", "estimate", "continue", "objective", "strategy", or the negative or comparable terminology, as well as terms usually used in the future and the conditional, are intended to identify forward-looking statements. Information contained in forward-looking statements is based upon certain material assumptions that were applied in drawing a conclusion or making a forecast or projection, including the assumptions, qualifications and limitations relating to advancement and development of the Project, the use of proceeds of the funds drawn down from the Credit Facility, the impact of the Credit Facility on the Company and its financial position and allocation, the contemplated work plan and activities at the Project and the timing, scope and results thereof and associated costs thereto, the ability and timing of the Company to reach commercial production (if at all), the ability of the Company to develop the next major Canadian gold mine at Cariboo, and the ability and timing of the Company to fulfill the conditions for subsequent advances under the Credit Facility and therefore draw the balance of the Credit Facility, the ability of the Company to raise or arrange the remaining funding required to complete the construction of Cariboo, the timing and ability of the Company to make a final investment decision, the final capital cost and timeline to build Cariboo, the ability of the Company to service and repay principal related to the Credit Facility whether from the operation of Cariboo or other sources of funds, the exploration potential at Tintic and San Antonio, the Company’s ability to develop long life, socially and environmentally responsible mining assets, the Company’s ability to grow mineral resources at any of its projects. These statements involve known and unknown risks, uncertainties and other factors that may cause actual results or events to differ materially from those anticipated in such forward-looking statements, including risks associated with fulfilling the conditions to a subsequent advance under the Credit Facility; the ability of the Company to comply with covenants under the Credit Facility; risks related to exploration and potential development, construction and operation of the Project; the accuracy of the estimated costs for the development activities at the Project and risks relating to cost overruns; the ability to seek additional funding (including project financing) for the Project; business and economic conditions in the mining industry generally; fluctuations in commodity prices and currency exchange rates; uncertainties relating to interpretation of drill results and the geology, continuity and grade of mineral deposits; regulatory framework and presence of laws and regulations that may impose restrictions on mining; the need to obtain additional financing to develop properties and uncertainty as to the availability and terms of future financing; and other risk factors facing the Company as disclosed in the Company’s most recent annual information form, financial statement and management’s discussion and analysis as well as other public filings on SEDAR+ (www.sedarplus.ca) and SEC’s EDGAR website (www.sec.gov) under the Company’s issuer profile.

Although the Company believes the expectations conveyed by the forward-looking statements are reasonable based on information available as of the date hereof, no assurances can be given as to future results, levels of activity and achievements. The Company disclaims any obligation to update any forward-looking statements, whether as a result of new information, future events or results or otherwise, except as required by law. Forward-looking statements are not guarantees of performance and there can be no assurance that these forward-looking statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news release. No stock exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein.