Mr. Sean Roosen reports

OSISKO DEVELOPMENT ANNOUNCES RESULTS OF ANNUAL AND SPECIAL MEETING OF SHAREHOLDERS AND GRANT OF DEFERRED SHARE UNITS

Osisko Development Corp. has released the results of its annual and special meeting of shareholders of the company held on June 23, 2026. Further information regarding the business of the meeting is contained in the company's management information circular dated May 11, 2026, which is available on SEDAR+ under the company's issuer profile.

A total of 226,058,370 common shares were voted at the meeting, representing approximately 74.19 per cent of the total issued and outstanding common shares of the company as of the record date of the meeting.

1. Election of directors

Each of the directors listed as nominees in the circular was elected to the board of directors of the company to serve for the ensuing year or until their successors are duly elected or appointed, with the results as shown in the attached table.

2. Appointment of auditor

PricewaterhouseCoopers LLP was reappointed as the company's independent auditor and the directors were authorized to fix the auditor's remuneration for the ensuing year, with the results as shown in the attached table.

3. Registered office resolution

The special resolution to approve the amendment to the articles of the company to change the province of the company's registered office from the Province of Quebec to the Province of Ontario, as outlined in the circular, was passed, with the results as shown in the attached table.

4. Name change resolution

The special resolution to approve the change of name of the company to Osisko Gold Group Inc., as outlined in the circular, was passed, with the results as shown in the attached table.

In connection with the company's name change to Osisko Gold Group, the company anticipates updating its stock ticker symbol for its listed securities on each of the TSX Venture Exchange and the New York Stock Exchange to OGG.

Grant of deferred share units

As part of the annual compensation review of its board of directors, the company granted 247,129 deferred share units of the company (DSUs) to its independent directors. The DSUs were granted in accordance with the company's omnibus equity incentive plan, which is available on the Osisko Development website.

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, United States, 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.