Dear Shareholders,

PetroVietnam Technical Services Corporation respectfully sends to Valued Shareholders and interested Investors Official Letter No. 1735/PTSC-BTK dated October 22, 2026 regarding disclosure of information on the Decision approving the change to the share listing registration of PetroVietnam Technical Services Corporation, as detailed in the attached document.

Sincerely./.

Attachment:
1735/PTSC-BTK