[SCHEDULE 13D/A] Tenaris S. A. SEC Filing

Rhea-AI Filing Summary

Tenaris S.A. (TS) – Schedule 13D/A Amendment No. 11 (dated 7 July 2025)

The filing updates the ownership position of the company’s long-standing controlling group – Rocca & Partners Stichting Administratiekantoor Aandelen San Faustin (RP STAK), San Faustin S.A. and Techint Holdings S.A r.l. – in Tenaris’s ordinary shares.

• Beneficial ownership: 713,605,187 ordinary shares, representing 67.5 % of the outstanding class based on 1,071,994,930 shares issued, net of 15,396,773 treasury shares as of 4 July 2025.
• Change vs. prior filing: Ownership percentage increased by 1.02 pp (from 66.52 % to 67.54 %). The shift is solely attributable to issuer share repurchases conducted between 24 Feb – 4 Mar 2025 (2024-25 buyback) and 9 Jun – 4 Jul 2025 (2025-26 buyback); the reporting persons executed no open-market transactions.
• Voting & dispositive power: RP STAK and San Faustin report shared voting/dispositive power over the full stake, whereas Techint Holdings reports sole power.
• Organisational structure: RP STAK (Dutch foundation) controls San Faustin (Luxembourg S.A.), which wholly owns Techint Holdings (Luxembourg S.à r.l.).
• Governance update: Filing notes “certain changes in the composition of the board of directors or management” of the reporting entities; specifics are not provided here but referenced in Exhibit 99.1.
• Recent activity: No criminal or civil proceedings involving the reporting persons or their principals over the past five years.

Investment take-away: The controlling group’s stake crossed the 67 % threshold without deploying additional capital, further entrenching its majority position and influence over corporate actions requiring a super-majority vote. The increase stems from Tenaris’s ongoing buyback programmes rather than insider accumulation.

Positive

• Ownership clarity: Filing confirms controlling shareholders now hold 67.5 % of outstanding shares, reinforcing governance stability.
• Non-dilutive increase: Percentage gain achieved through Tenaris’s share buybacks rather than insider purchases, implying no additional cash outlay by control group.
• No adverse legal matters: Reporting persons disclose no criminal or civil proceedings within the last five years.

Negative

• None.

Insights

Equity Governance Analyst

TL;DR: Control group up to 67.5 % via buybacks; no insider buying—impact modestly positive for governance clarity.

The amendment confirms that the Rocca/San Faustin/Techint consortium now controls 67.5 % of Tenaris, 1.02 pp higher than February 2025. The mechanics matter: ownership rose purely because Tenaris shrank its float through two disclosed buyback tranches. No shares were purchased by the reporting parties, meaning cash deployment came from the issuer, not insiders.
For investors, the filing reinforces: (1) entrenched majority control—any shareholder resolutions will pass with the group’s backing; (2) continued capital-return policy by Tenaris; (3) no dilution or sale by the controlling block, signalling commitment. Governance risk for minorities is unchanged, but the clarity is directionally positive. The absence of legal proceedings or recent insider trades removes immediate red flags.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 11)

Tenaris SA

(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
35227209600

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

07/07/2025

(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)

67.5 %

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. 11 are calculated based on 1,071,994,930 issued Ordinary Shares (as defined below), of which 15,396,773 were held by Tenaris S.A. as treasury stock as of July 4, 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)

67.5 %

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. 11 are calculated based on 1,071,994,930 issued Ordinary Shares (as defined below), of which 15,396,773 were held by Tenaris S.A. as treasury stock as of July 4, 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)

67.5 %

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. 11 are calculated based on 1,071,994,930 issued Ordinary Shares (as defined below), of which 15,396,773 were held by Tenaris S.A. as treasury stock as of July 4, 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 SA
(c)	Address of Issuer's Principal Executive Offices: 26, BOULEVARD ROYAL, 4TH FLOOR, LUXEMBOURG, LUXEMBOURG , L-2449.
Item 1 Comment: This Amendment No. 11 amends and supplements the Schedule 13D originally filed on February 14, 2011 (this "Amendment No. 11"), as further amended by Amendments No. 1, No. 2, No. 3, No. 4, No. 5, No. 6, No. 7, No. 8, No. 9 and No. 10, on behalf of RP STAK, SAN FAUSTIN and TECHINT HOLDINGS (as defined thereunder), relating to the Ordinary Shares, par value $1 per share of Tenaris S.A. (the "Ordinary Shares"). This Amendment No. 11 reflects (i) an increase by 1.02% of the percent of class represented by the Ordinary Shares held by such Reporting Persons, from 66.52% to 67.54%, 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 February 24, 2025 to March 4, 2025, under Tenaris S.A.'s 2024-2025 share buyback program publicly announced on November 10, 2024 and then in the period from June 9 until July 4, 2025, under Tenaris S.A.'s 2025-2026 share buyback program publicly announced on May 27, 2025; and (ii) certain changes in the composition of the board of directors or management of certain Reporting Persons. Except as specifically provided herein, this Amendment No. 11 does not modify any of the information previously reported on the Schedule 13D and its amendments.
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. RP STAK is a private foundation (stichting) organized under the laws of The Netherlands. No person or group of persons controls RP STAK.
(b)	SAN FAUSTIN S.A. ("SAN FAUSTIN") 26, Boulevard Royal, Ground Floor, L-2449 Luxembourg. 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).
(c)	TECHINT HOLDINGS S.A R.L. ("TECHINT HOLDINGS") 26, Boulevard Royal, Ground Floor, L-2449 Luxembourg. 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. 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 hereto and is incorporated into this Item 2 by reference. 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 hereto, has (i) been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors) or (ii) 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 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)	There have been no transactions in Ordinary Shares effected by the Reporting Persons or, to the best of the Reporting Person's knowledge, any person or entity identified on Exhibit 99.1 hereto, during the last 60 days.
(d)	Not applicable.
(e)	Not applicable.
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.* D Exhibit 99.1 - Directors and Execetive Officers of Reporting Persons *Previously filed as an exhibit to the Amendement No. 5 to the Schedule 13D of Tenaris S.A. dated November 2, 2023 and incorporated by reference in this Amendment No. 11.

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:	/s/ Fernando J. Mantilla
Name/Title:	Fernando J. Mantilla/Attorney-in-fact
Date:	07/07/2025

SAN FAUSTIN S.A.

Signature:	/s/ Fernando J. Mantilla
Name/Title:	Fernando J. Mantilla/Attorney-in-fact
Date:	07/07/2025

TECHINT HOLDINGS S.A R.L.

Signature:	/s/ Fernando J. Mantilla
Name/Title:	Fernando J. Mantilla/Attorney-in-fact
Date:	07/07/2025

FAQ

How many Tenaris (TS) shares do the reporting persons own according to the July 2025 Schedule 13D/A?

They beneficially own 713,605,187 ordinary shares, equal to 67.5 % of the class.

Did the controlling shareholders buy additional TS shares to raise their ownership?

No. The 1.02 pp increase stems from Tenaris’s open-market share repurchases, not insider buying.

Which entities make up the controlling group disclosed in this filing?

Rocca & Partners Stichting Administratiekantoor Aandelen San Faustin, San Faustin S.A., and Techint Holdings S.A r.l.

What voting power do the reporting persons hold over Tenaris shares?

RP STAK and San Faustin report shared voting/dispositive power; Techint Holdings reports sole voting/dispositive power over the same stake.

Were there any insider transactions by the reporting group in the last 60 days?

The filing states no transactions in Tenaris ordinary shares by the reporting persons during that period.

Why did Tenaris’s share count decrease?

Tenaris executed buybacks under its 2024-25 and 2025-26 share repurchase programmes, reducing the float and increasing the control group’s percentage interest.