Company: TNRSF
Filing Date: 2025-12-18
Form Type: 6-K
Source: 0001171843-25-007991
Chunk: 0

Company: TENARIS SA
Filing Date: 2025-12-18
Form: 6-K
Chunk 0
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<div align='center'>FORM 6 - K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Report of Foreign Private Issuer

Pursuant to Rule 13a - 16 or 15d - 16 of

the Securities Exchange Act of 1934</div>

As of December 17, 2025

<div align='center'>TENARIS, S.A.

(Translation of Registrant's name into English)

26, Boulevard Royal, 4th floor

L-2449 Luxembourg

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or 40-F.

Form 20-F Ö Form 40-F ___</div>

The attached material is being furnished to the Securities and Exchange Commission pursuant to Rule 13a-16 and Form 6-K under the Securities Exchange Act of 1934, as amended. This report contains Tenaris’s Press Release announcing Repurchased own ordinary shares reached 5% of Tenaris’s voting rights; Tenaris’s controlling shareholder files amendment to Schedule 13D.

<div align='center'>SIGNATURE</div>

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: December 17, 2025

<div align='center'>Tenaris, S.A.</div>

By: /s/ Giovanni Sardagna

Giovanni Sardagna

Investor Relations Officer

Giovanni Sardagna

Tenaris

1-888-300-5432

www.tenaris.com

Repurchased own ordinary shares reached 5% of Tenaris’s voting rights; Tenaris’s controlling shareholder files amendment to Schedule 13D

Luxembourg, December 17, 2025. -Pursuant to applicable Luxembourg Transparency Law requirements, Tenaris S.A. (NYSE and Mexico: TS and EXM Italy: TEN) (“Tenaris” or the “Company”) announces that on December 17, 2025, the proportion of own ordinary shares acquired under its share buyback program and currently held in treasury has reached 5.07% of Tenaris’s voting rights. Ordinary shares repurchased under such program are being held in treasury (with their voting rights suspended) and will be cancelled in due course. Reporting of share buyback transactions in