[SCHEDULE 13D/A] TENARIS SA SEC Filing

Rhea-AI Filing Summary

Amendment No. 12 to the Schedule 13D for Tenaris S.A. reports that the Reporting Persons collectively hold 713,605,187 Ordinary Shares, representing 68.45% of issued shares following Tenaris S.A.'s open-market repurchases made under its 2025-2026 buyback program. The amendment notes that SAN FAUSTIN's board authorized TECHINT HOLDINGS to sell some of its shares for portfolio-management purposes, provided TECHINT HOLDINGS' ownership does not fall below 67% of outstanding Ordinary Shares. The filing confirms no transactions by the Reporting Persons in the last 60 days and otherwise incorporates prior Schedule 13D disclosures by reference.

Insights

Financial Analyst

TL;DR: Controlling holders' stake rose to 68.45% due to buybacks; limited authorization to sell maintains a 67% ownership floor.

The increment in reported beneficial ownership to 68.45% is a passive effect of Tenaris' open-market repurchases and signals consolidated control by the Reporting Persons. Authorizing TECHINT HOLDINGS to sell while preserving a minimum 67% stake provides liquidity flexibility without relinquishing control. The absence of transactions in the prior 60 days suggests no immediate disposition. For investors, this preserves governance stability while allowing limited portfolio adjustments by the controlling group.

Corporate Governance Expert

TL;DR: Governance control remains firmly with the Reporting Persons; the sale authorization includes an explicit ownership floor.

The Reporting Persons continue to exercise dominant voting power with shared or sole voting/dispositive power over 713,605,187 shares (68.45%). The board-level authorization that permits sales but caps downward movement at 67% balances fiduciary flexibility and control preservation. The amendment updates prior disclosures without indicating material governance changes beyond this limited sale authorization.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 12)

Tenaris S.A.

(Name of Issuer)

Ordinary Shares, $1.00 par value per share

(Title of Class of Securities)

88031M109

(CUSIP Number)

Fernando J. Mantilla
26, Boulevard Royal, Ground Floor,,
Grand-Duchy of Luxembourg, N4, L-2449
352 27209600

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

09/17/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 88031M109

1

Name of reporting person

ROCCA & PARTNERS STICHTING ADMINISTRATIEKANTOOR AANDELEN SAN FAUSTIN

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

NETHERLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 713,605,187.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 713,605,187.00

11

Aggregate amount beneficially owned by each reporting person

713,605,187.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

68.5 %

14

Type of Reporting Person (See Instructions)

HC

Comment for Type of Reporting Person:

Note to Row 4 (Source of funds): please refer to "Item 1 Comment" below. Note to Row 13 (Percent of class represented by amount in Row (11)): The percent of class figures set forth in this Amendment No. 12 are calculated based on 1,071,994,930 issued Ordinary Shares (as defined below), of which 29,499,198 were held by Tenaris S.A. as treasury stock as of September 12, 2025, as published on the website of Tenaris S.A.

SCHEDULE 13D

CUSIP No. 88031M109

1

Name of reporting person

SAN FAUSTIN S.A.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

LUXEMBOURG

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 713,605,187.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 713,605,187.00

11

Aggregate amount beneficially owned by each reporting person

713,605,187.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

68.5 %

14

Type of Reporting Person (See Instructions)

CO

Comment for Type of Reporting Person:

Note to Row 4 (Source of funds): please refer to "Item 1 Comment" below. Note to Row 13 (Percent of class represented by amount in Row (11)): The percent of class figures set forth in this Amendment No. 12 are calculated based on 1,071,994,930 issued Ordinary Shares (as defined below), of which 29,499,198 were held by Tenaris S.A. as treasury stock as of September 12, 2025, as published on the website of Tenaris S.A.

SCHEDULE 13D

CUSIP No. 88031M109

1

Name of reporting person

TECHINT HOLDINGS S.A R.L.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

LUXEMBOURG

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 713,605,187.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 713,605,187.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

713,605,187.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

68.5 %

14

Type of Reporting Person (See Instructions)

CO

Comment for Type of Reporting Person:

Note to Row 4 (Source of funds): please refer to "Item 1 Comment" below. Note to Row 13 (Percent of class represented by amount in Row (11)): The percent of class figures set forth in this Amendment No. 12 are calculated based on 1,071,994,930 issued Ordinary Shares (as defined below), of which 29,499,198 were held by Tenaris S.A. as treasury stock as of September 12, 2025, as published on the website of Tenaris S.A.

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Ordinary Shares, $1.00 par value per share
(b)	Name of Issuer: Tenaris S.A.
(c)	Address of Issuer's Principal Executive Offices: 26, BOULEVARD ROYAL, 4TH FLOOR, LUXEMBOURG, LUXEMBOURG , L-2449.
Item 1 Comment: This Amendment No. 12 amends and supplements the Schedule 13D originally filed on February 14, 2011 (this "Amendment No. 12"), as further amended by Amendments No. 1, No. 2, No. 3, No. 4, No. 5, No. 6, No. 7, No. 8, No. 9, No. 10 and No. 11, on behalf of RP STAK, SAN FAUSTIN and TECHINT HOLDINGS (each as defined under Item 2 below) (collectively, the "Reporting Persons"), relating to the Ordinary Shares, par value $1 per share of Tenaris S.A. (the "Ordinary Shares"). This Amendment No. 12 reflects (i) the authorization given by SAN FAUSTIN's board of directors to TECHINT HOLDINGS to sell a number of its Ordinary Shares, provided that TECHINT HOLDINGS' ownership stake in Tenaris S.A. should not fall below 67 percent of the total outstanding Ordinary Shares (see Item 4 below) and (ii) an increase by 0.91% of the percent of class represented by the Ordinary Shares held by such Reporting Persons, from 67.54% to 68.45%, as reported on Rows 13 of the cover pages of this Schedule 13D, as a result of repurchases of Ordinary Shares made by Tenaris S.A. in the open market in the period from July 7, 2025 to September 12, 2025, under Tenaris S.A.'s 2025-2026 share buyback program publicly announced on May 27, 2025. Except as specifically provided herein, this Amendment No. 12 does not modify any of the information previously reported on the Schedule 13D and its amendments. This Schedule 13D is being jointly filed by each of the Reporting Persons pursuant to Rule 13d-1(k).
Item 2.	Identity and Background
(a)	ROCCA & PARTNERS STICHTING ADMINISTRATIEKANTOOR AANDELEN SAN FAUSTIN ("RP STAK"). Fascinatio Boulevard 764, 2909 VA Capelle aan den IJssel, The Netherlands. SAN FAUSTIN S.A. ("SAN FAUSTIN") 26, Boulevard Royal, Ground Floor, L-2449 Luxembourg. TECHINT HOLDINGS S.A R.L. ("TECHINT HOLDINGS") 26, Boulevard Royal, Ground Floor, L-2449 Luxembourg.
(b)	RP STAK is a private foundation (stichting) organized under the laws of The Netherlands. No person or group of persons controls RP STAK SAN FAUSTIN is a societe anonyme (public limited liability company) organized under the laws of the Grand-Duchy of Luxembourg. RP STAK continues to control SAN FAUSTIN (i.e. it continues to have the ability to influence matters affecting, or submitted to a vote of the shareholders of SAN FAUSTIN, including the election of directors and the approval of certain corporate transactions and other matters concerning SAN FAUSTIN's policies). TECHINT HOLDINGS is a societe a responsabilite limitee (private limited liability company) organized under the laws of the Grand-Duchy of Luxembourg. All of the shares of TECHINT HOLDINGS are held by SAN FAUSTIN.
(c)	The name, residence or business address, present principal occupation or employment (and the name, principal business and address of any corporation or other organization in which such employment is conducted) and citizenship of each voting committee member, executive officer or director, as applicable, of each Reporting Person are set forth in Exhibit 99.1 to the Amendment No. 11 to the Schedule 13D of Tenaris S.A., filed on July 8, 2025, and is incorporated into this Item 2 by reference.
(d)	During the last five years, none of the Reporting Persons, nor, to the knowledge of the Reporting Persons, none of the persons listed on Exhibit 99.1 to the Amendment No. 11 to the Schedule 13D of Tenaris S.A., filed on July 8, 2025, has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors). Information with respect to each of the Reporting Persons is given solely by such Reporting Person, and no Reporting Person assumes responsibility for the accuracy or completeness of information given by another Reporting Person.
(e)	During the last five years, none of the Reporting Persons, nor, to the knowledge of the Reporting Persons, none of the persons listed on Exhibit 99.1 to the Amendment No. 11 to the Schedule 13D of Tenaris S.A., filed on July 8, 2025, has been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to federal or state securities laws or finding any violation with respect to such laws. Information with respect to each of the Reporting Persons is given solely by such Reporting Person, and no Reporting Person assumes responsibility for the accuracy or completeness of information given by another Reporting Person.
Item 4.	Purpose of Transaction
	The last disclosure paragraph of the response set forth in Item 4 of the Schedule 13D originally filed on February 14, 2011, is hereby deleted in its entirety and replaced with the following: For portfolio-management purposes and in response to Tenaris S.A.'s ongoing share repurchase program causing SAN FAUSTIN's beneficial ownership interest in Tenaris S.A. to passively increase, on September 17, 2025, the board of directors of SAN FAUSTIN authorized TECHINT HOLDINGS to sell a number of its Ordinary Shares, provided that TECHINT HOLDINGS' ownership stake in Tenaris S.A. should not fall below 67 percent of the total outstanding Ordinary Shares. The precise timing, amount and manner of any such sales will depend upon market conditions and other factors, and there is no assurance that any sales will be completed or the timing thereof. Although the Reporting Persons do not currently intend to purchase Ordinary Shares or to reduce their beneficial ownership below 67 percent of the total outstanding Ordinary Shares, they may from time to time, depending on market conditions and other factors, purchase or sell additional Ordinary Shares. Except as described in this Schedule 13D, the Reporting Persons do not have any present plans or proposals that relate to or would result in any of the actions described in subparagraphs (a) through (j) of Item 4 of Schedule 13D.
Item 5.	Interest in Securities of the Issuer
(a)	RP STAK. See items (7) through (11) and (13) on page 2 SAN FAUSTIN. See items (7) through (11) and (13) on page 3 TECHINT HOLDINGS. See items (7) through (11) and (13) on page 4
(b)	RP STAK. See items (7) through (11) and (13) on page 2 SAN FAUSTIN. See items (7) through (11) and (13) on page 3 TECHINT HOLDINGS. See items (7) through (11) and (13) on page 4
(c)	During the last 60 days, there have been no transactions in Ordinary Shares effected by the Reporting Persons or, to the best of the Reporting Person's knowledge, any of the persons listed on Exhibit 99.1 to the Amendment No. 11 to the Schedule 13D of Tenaris S.A., filed on July 8, 2025.
(d)	N/A
(e)	N/A
Item 7.	Material to be Filed as Exhibits.
	A Power of Attorney of ROCCA & PARTNERS STICHTING ADMINISTRATIEKANTOOR AANDELEN SAN FAUSTIN dated October 31st, 2023.* B Power of Attorney of SAN FAUSTIN S.A., dated September 28, 2023.* C Power of Attorney of TECHINT HOLDINGS S.a r.l., dated September 28, 2023.* *Previously filed as an exhibit to the Amendment No. 5 to the Schedule 13D of Tenaris S.A. filed on November 3, 2023 and incorporated by reference in this Amendment No. 12.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

ROCCA & PARTNERS STICHTING ADMINISTRATIEKANTOOR AANDELEN SAN FAUSTIN

Signature:	ROCCA & PARTNERS STICHTING ADMINISTRATIEKANTOOR AANDELEN SAN FAUSTIN
Name/Title:	/s/ Fernando J. Mantilla / Attorney-in-fact
Date:	09/19/2025

SAN FAUSTIN S.A.

Signature:	SAN FAUSTIN S.A.
Name/Title:	/s/ Fernando J. Mantilla / Attorney-in-fact
Date:	09/19/2025

TECHINT HOLDINGS S.A R.L.

Signature:	TECHINT HOLDINGS S.A R.L.
Name/Title:	/s/ Fernando J. Mantilla / Attorney-in-fact
Date:	09/19/2025

Comments accompanying signature:

Pursuant to Rule 13d-1(k)(1), the undersigned joins in the filing of this Amendment No. 12 on his own behalf and on behalf of SAN FAUSTIN S.A. and TECHINT HOLDINGS S.A R.L. Pursuant to Rule 13d-1(k)(1), the undersigned joins in the filing of this Amendment No. 12 on his own behalf and on behalf of ROCCA & PARTNERS STICHTING ADMINISTRATIEKANTOOR AANDELEN SAN FAUSTIN and TECHINT HOLDINGS S.A R.L. Pursuant to Rule 13d-1(k)(1), the undersigned joins in the filing of this Amendment No. 12 on his own behalf and on behalf of ROCCA & PARTNERS STICHTING ADMINISTRATIEKANTOOR AANDELEN SAN FAUSTIN and SAN FAUSTIN S.A.