Osisko Development Corp. — AGM Information 2024

Feb 22, 2024

TMX

THE FUTURE IS YOURS TO SEE.

TSX TRUST COMPANY

VIA ELECTRONIC TRANSMISSION

February 22, 2024

TO ALL APPLICABLE EXCHANGES AND COMMISSIONS:

RE: OSISKO DEVELOPMENT CORP. Confirmation of Notice of Record and Meeting Dates

We are pleased to confirm that Notice of Record and Meeting Dates was sent to The Canadian Depository for Securities.

We advise the following with respect to the upcoming Annual General Meeting of Security Holders for the subject issuer:

1. ISIN: CA68828E8099 CUSIP: 68828E809

2. Date Fixed for the Meeting: May 7, 2024

3. Record Date for Notice: March 18, 2024

4. Record Date for Voting: March 18, 2024

5. Beneficial Ownership Determination Date: March 18, 2024

6. Classes or Series of Securities that entitle the holder to receive Notice of the Meeting: COMMON SHARES

7. Classes or Series of Securities that entitle the holder to vote at the meeting: COMMON SHARES

8. Business to be conducted at the meeting: Annual General

9. Notice-and-Access: Registered Shareholders: YES Beneficial Holders: YES Stratification Level: Not Applicable

10. Reporting issuer is sending proxy-related materials directly to Non-Objecting Beneficial Owners: YES

11. Issuer paying for delivery to Objecting Beneficial Owners: YES

Yours truly, TSX Trust Company

VANCOUVER 733 Seymour Street, Suite #2310 Vancouver, BC V6B 0S6 T 604 689-3334

CALGARY Telus Sky Building 2110, 685 Centre Street SW Calgary Alberta T2G 1S5 T 403 218-2800

TORONTO 301 - 100 Adelaide Street West Toronto ON M5H 4H1 Toll Free 1-866-600-5869 T 416 361-0930

MONTRÉAL 1701 - 1190, avenue des Canadiens-de-Montréal, C. P. 37 Montréal (Québec) H3B 0G7 T 514 395-5964