Tenaris Announces Brazilian Superior Court Rejects Motion To Reverse Ruling Ordering T/T Group To Pay CSN Indemnification Related To 2012 Usiminas Acquisition, Lowers Potential Liability To ~$90M; Tenaris Maintains Claims Are Without Merit And Will Continue To Vigorously Defend Against SCJ Decisions

Tenaris S.A. announced that the Brazilian Superior Court of Justice (SCJ) published today its unanimous decision to reject a motion of clarification filed by Tenaris's subsidiary Confab, together with Ternium's subsidiaries Ternium Investments and Ternium Argentina (all of which compose the T/T Group under the Usiminas shareholders agreement), that had sought to revert the June 18, 2024 SCJ decision ordering the T/T Group to pay Companhia Siderúrgica Nacional, or CSN, an indemnification in connection with their 2012 acquisition of a participation in Usiminas.

Notwithstanding the foregoing, the SCJ unanimously resolved to modify the applicable monetary adjustment mechanism and to cap the applicable attorney's fees, thereby lowering the aggregate amount that would be payable by the T/T Group if CSN ultimately prevails in its claims. Assuming monetary adjustment through November 30, 2024, and BRL 5 million in attorney's fees, in each case as determined pursuant to the SCJ decision published today, the revised aggregate amount potentially payable by Confab would be of approximately BRL548 million (approximately $90 million).

Tenaris continues to believe that all of CSN's claims and allegations are unsupported and without merit, and that in connection with the Usiminas acquisition the T/T Group was not required either to launch a tender offer or to pay indemnification to CSN. Accordingly, Confab intends to continue to defend its rights vigorously and to file all available motions and appeals against the SCJ decisions that ordered an indemnification payment.