Osisko Development Announces Nomination of Keith McKay to the Board of Directors and Proposes Name Change to Osisko Gold Group Inc. at Upcoming Annual and Special Meeting of Shareholders

Executive Summary

• Osisko Development Corp. announced its upcoming annual and special meeting scheduled for June 23, 2026, in Toronto.
• The company nominated Keith McKay to replace outgoing non-executive director Duncan Middlemiss on the Board of Directors, with all other incumbent directors also up for re-election.
• Shareholders will vote on a proposed change of the company's name to "Osisko Gold Group Inc." to better align with its strategic evolution toward a primary gold and precious metals-focused asset base in North America.

Key Details

• Meeting Logistics: June 23, 2026, at 1:30 p.m. Eastern Time; First Canadian Place, 100 King St. W., Suite 3400, Toronto, Ontario.
• Director Nomination: Keith McKay nominated to succeed Duncan Middlemiss; incumbent directors nominated for re-election.
• New Director Qualifications: Chartered Professional Accountant with 45+ years of finance and executive leadership experience in mining/natural resources. Currently CFO of Dalradian Resources Inc. (since June 2010). Former CFO of Continental Gold Ltd., Andina Minerals Inc., and Aurelian Resources Inc. Served as director and Audit Committee Chair for Osisko Mining Inc., O3 Mining Inc., and Noront Resources Ltd. Holds a BA from Western University and CA designation (1981).
• Proposed Name Change: Vote to change corporate name to "Osisko Gold Group Inc." to reflect the company's shift toward a primary gold and precious metals focus in North America, coinciding with the de-risking and advancement of its fully permitted Cariboo Gold Project.
• Reference Materials: Management information circular dated May 11, 2026, filed with securities regulators and available on SEDAR+ and the company website.

Notable Quotes

• "On behalf of the Board and management team, I would like to thank Duncan for his valuable contributions and dedicated service," said Sean Roosen, Chairman and CEO. "We've greatly benefited from his guidance and commitment during his tenure, and we wish him all the best in his future endeavours."