Company: TNRSF
Filing Date: 2025-09-19
Form Type: 6-K
Source: 0001171843-25-005985
Chunk: 0

Company: TENARIS SA
Filing Date: 2025-09-19
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 September 19, 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 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 Tenaris’s controlling shareholder files an amendment to Schedule 13D in response to Tenaris’s ongoing share buyback
program.

.

<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: September 19, 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

Tenaris’s controlling shareholder files an amendment to Schedule 13D in response to Tenaris’s ongoing share buyback program

Luxembourg, September 19, 2025. - Tenaris S.A. (NYSE and Mexico:
TS and EXM Italy: TEN) (“Tenaris”, or the “Company”) announced that its indirect controlling shareholder San Faustin
S.A. and its direct controlling shareholder Techint Holdings S.à r.l. (the “Reporting Persons”) filed earlier today
with the SEC an amendment to their Schedule 13D, reporting that, for portfolio-management purposes and in response to Tenaris’s
ongoing share repurchase program causing San Faustin’s beneficial ownership interest in Tenaris to passively increase, on September