Osisko Gold Group Inc.

APPENDIX & EXHIBITS

ANNEX I ― Rule 144A / Regulation S

ANNEX II ― Disbursement Schedule

ANNEX III ― Approved Budget

EXHIBIT 1 to Rule 144A / Regulation S — Form of Initial Note

EXHIBIT A — Form of Supplemental Indenture to Be Delivered by Subsequent Guarantors

EXHIBIT B — Form of Incumbency Certificate

EXHIBIT C — Form of Net Short Representation

EXHIBIT D — Form of Disbursement Request

EXHIBIT E — Form of U.S. Security Agreement

v

INDENTURE, dated as of September 30, 2026 (this “Indenture”), among OSISKO GOLD GROUP INC., a corporation existing under theCanada Business Corporations Act, the Guarantors (as defined herein) party hereto, COMPUTERSHARE TRUST COMPANY, N.A., a national banking association organized under the laws of the United States, not in its individual capacity, but solely in its representative capacity, as U.S. Trustee, and COMPUTERSHARE ADVANTAGE TRUST OF CANADA, not in its individual capacity, but solely in its capacity as Canadian Trustee and as Collateral Agent.