TST: Change in shareholding of principal shareholder (VDT Scientific Data Joint Stock Company)

- Name of issuer: Telecommunication Technical Service Joint Stock Company
- Stock code: TST
- Securities type: common stock
- Name of principal shareholder: VDT Scientific Data Joint Stock Company
- Number of shares held by the principal shareholder before transaction: 614,300 shares (12.8%)
- Number of shares acquired: 97,100 shares
- Total holding following transaction and total percentage following transaction: 711,400 shares (14.82%)
- Purpose of transaction: Increase ownership
- Date of transaction: 07/03/2025