Mr. Sean Roosen reports

OSISKO DEVELOPMENT TO COMPLETE FOURTH DEFERRED PAYMENT INSTALLMENT IN CONNECTION WITH THE TINTIC ACQUISITION

In accordance with the terms of Osisko Development Corp.'s previously completed acquisition in May, 2022, of a 100-per-cent ownership interest in the Tintic project, located in Utah, United States, the company intends to satisfy the fourth of five deferred payments to certain sellers of the Tintic project (the sellers) in common shares of the company.

The fourth deferred payment of $2.5-million (U.S.) (or $3,453,000 based on a United Stats-dollar/Canadian-dollar exchange rate of 1.3812) is expected to be paid entirely in common shares at a deemed price of approximately $3.9613 per common share (based on the 20-day VWAP (volume-weighted average price) as of the closing of the market on May 26, 2026), resulting in the issuance of 871,683 common shares to the sellers in full satisfaction of the fourth deferred payment.

The issuance of the common shares in satisfaction of the fourth deferred payment remains subject to the approval of the TSX Venture Exchange.

For additional details regarding the Tintic acquisition, please refer to the company's news releases dated Jan. 25, 2022 (entitled "Osisko Development Announces Proposed Acquisition of Tintic Consolidated Metals"), and May 30, 2022 (entitled "Osisko Development Completes Acquisition of Tintic Consolidated Metals, Finalizes Binding Stream Terms and Satisfies Escrow Release Condition For Brokered Subscription Receipt Financing").

About Osisko Development Corp.

Osisko Development is a continental North American gold development company focused on past-producing mining camps with district-scale potential. The company's objective is to become an intermediate gold producer through the development of its flagship, fully permitted, 100-per-cent-owned Cariboo gold project, located in central British Columbia, Canada. Its project pipeline is complemented by the Tintic project located in the historic East Tintic mining district in Utah, U.S., a brownfield property with significant exploration potential, extensive historical mining data and access to established infrastructure. Osisko Development is focused on developing long-life mining assets in mining-friendly jurisdictions while maintaining a disciplined approach to capital allocation, development risk management and mineral inventory growth.

We seek Safe Harbor.