Osisko Development Corp. — Regulatory Filings 2021

Apr 9, 2021

CERTIFICATE

Section 2.20(c) of National Instrument 54-101

• TO: British Columbia Securities Commission (Principal regulator) Alberta Securities Commission Autorité des marchés financiers

• RE: Annual Meeting of Shareholders of Osisko Development Corp. (the “ Corporation ”) to be held on May 12, 2021 (the “ Meeting ”)

In connection with the Corporation’s Meeting, the undersigned, being an officer of the Corporation, hereby certifies for and on behalf of the Corporation, and not in his personal capacity, that:

• (a) arrangements have been made to have the proxy-related materials for the Meeting delivered in compliance with the applicable timing requirements in Sections 2.9 and 2.12 of National Instrument 54-101 Communication with Beneficial Owners of Securities of a Reporting Issuer (“ NI 54-101 ”);

• (b) the Corporation has arranged to have carried out all of the requirements of NI 54101 in addition to those described in paragraph (a) above; and

• (c) the Corporation is relying upon Section 2.20(c) of NI 54-101 to abridge the time periods prescribed by sections 2.2(1) and 2.5(1) of NI 54-101 applicable to the Meeting.

Dated this 9[th] day of April 2021.

OSISKO DEVELOPMENT CORP.

• (s) André Le Bel

André Le Bel Corporate Secretary