Controlling group in Tenaris (TS) cuts stake to 68.55% after share sales

Rhea-AI Filing Summary

Tenaris S.A.’s controlling shareholder group has modestly reduced its stake through open-market sales while retaining clear control. RP STAK, San Faustin and Techint Holdings now beneficially own 692,085,486 ordinary shares, representing 68.55% of Tenaris’s outstanding ordinary shares, excluding treasury stock.

The ownership percentage fell from 69.66% to 68.55% after Techint Holdings sold 18,919,701 ordinary shares in the open market between December 15, 2025 and February 6, 2026 under a non‑discretionary accelerated share disposal agreement. This decrease was partially offset by Tenaris’s open‑market repurchase of 11,065,751 ordinary shares over a similar period.

Insights

Equity ownership and governance analyst

Controlling group trims Tenaris stake slightly but remains firmly in control.

The reporting group (RP STAK, San Faustin and Techint Holdings) discloses beneficial ownership of 692,085,486 Tenaris ordinary shares, or 68.55% of the class. This still represents a strong controlling position over shareholder votes and strategic decisions.

The stake declined from 69.66% to 68.55% after Techint Holdings sold 18,919,701 shares via an accelerated disposal agreement, partly offset by Tenaris repurchasing 11,065,751 shares. The change is relatively small in percentage terms, so governance dynamics appear largely unchanged based on this information.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 14)

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)

02/06/2026

(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 692,085,486.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 692,085,486.00

11

Aggregate amount beneficially owned by each reporting person

692,085,486.00

12

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

13

Percent of class represented by amount in Row (11)

68.6 %

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. 14 are calculated based on 1,071,994,930 issued Ordinary Shares (as defined below), of which 62,328,172 were held by Tenaris S.A. as treasury stock as of January 2, 2026, 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 692,085,486.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 692,085,486.00

11

Aggregate amount beneficially owned by each reporting person

692,085,486.00

12

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

13

Percent of class represented by amount in Row (11)

68.6 %

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. 14 are calculated based on 1,071,994,930 issued Ordinary Shares (as defined below), of which 62,328,172 were held by Tenaris S.A. as treasury stock as of January 2, 2026, 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 692,085,486.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 692,085,486.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

692,085,486.00

12

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

13

Percent of class represented by amount in Row (11)

68.6 %

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. 14 are calculated based on 1,071,994,930 issued Ordinary Shares (as defined below), of which 62,328,172 were held by Tenaris S.A. as treasury stock as of January 2, 2026, 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. 14 amends and supplements the Schedule 13D originally filed on February 14, 2011 (this "Amendment No. 14"), as further amended by Amendments No. 1 to No. 13, 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. 14 reflects a net decrease by 1.11% of the percent of class represented by the Ordinary Shares held by such Reporting Persons, from 69.66% to 68.55%, as reported on Rows 13 of the cover pages of the Schedule 13D, as a result of the sale of a total of 18,919,701 Ordinary Shares by TECHINT HOLDINGS in the open market in the period from December 15, 2025 to February 6, 2026, under the non-discretionary accelerated share disposal agreement entered into by TECHINT HOLDINGS with an European financial institution reported in Item 4 of Amendment No. 13 to the Schedule 13D, which decrease was partially offset by the effect of the repurchase of a total of 11,065,751 Ordinary Shares made by Tenaris S.A. in the open market in the period from December 15, 2025 to January 2, 2026 under the second tranche of the share buyback program publicly announced on November 2, 2025. Except as specifically provided herein, this Amendment No. 14 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 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)	In the period from December 15, 2025 to February 6, 2026, TECHINT HOLDINGS effected the following sales of Ordinary Shares pursuant to a non-discretionary accelerated share disposal agreement entered into with an European financial institution regulated in the European Union: Range of Prices Trade Date Number of Ordinary Weighted Average Min Daily price Max Daily price Shares Sold Sale Price (+) (USD) (+) (USD) (+) 12/15/25 340.000 20,2440 20,0741 20,3327 12/16/25 340.000 19,9753 19,7130 20,1841 12/17/25 358.884 19,8353 19,6871 19,9919 12/18/25 340.000 19,5568 19,1195 19,8813 12/19/25 340.000 19,0721 18,8622 19,2370 12/22/25 309.822 19,1899 19,0974 19,2853 12/23/25 30.585 19,2886 19,0815 19,3998 12/29/25 10.000 19,2609 19,1845 19,3668 12/30/25 150.000 19,3747 19,3403 19,4226 01/02/26 300.000 19,3218 19,1521 19,3983 01/05/26 695.000 19,9610 19,7063 20,2254 01/06/26 1.247.563 20,4786 20,1829 20,6570 01/07/26 39.850 19,9890 19,9329 20,1082 01/08/26 666.433 19,8369 19,6841 19,9292 01/09/26 714.646 20,1155 19,8962 20,4259 01/12/26 663.268 20,1900 19,9758 20,3207 01/13/26 515.382 20,5316 20,1381 20,8257 01/14/26 762.119 20,8836 20,6980 21,0708 01/15/26 843.820 21,0390 20,8941 21,1324 01/16/26 292.584 20,8172 20,6202 20,9048 01/19/26 455.953 20,8225 20,7497 20,8893 01/20/26 480.933 21,0436 20,8289 21,2101 01/21/26 443.221 21,7492 21,4472 21,9695 01/22/26 893.668 22,0625 21,8668 22,3526 01/23/26 678.580 22,4073 22,1043 22,6679 01/26/26 856.644 22,1810 21,9617 22,3819 01/27/26 714.859 22,2186 22,0567 22,3907 01/28/26 801.346 22,2761 22,1519 22,4093 01/29/26 644.778 22,6451 22,2964 22,9127 01/30/26 697.655 22,2488 22,0859 22,3481 02/02/26 578.422 22,0486 21,5547 22,2474 02/03/26 692.610 22,5759 22,3098 22,9293 02/04/26 671.026 23,1213 22,9131 23,3681 02/05/26 645.913 22,9515 22,7347 23,2303 02/06/26 704.137 23,0932 22,8568 23,2932 (+) For the purposes of this report, all euro prices were converted into U.S. dollars at the European Central Bank (ECB) reference exchange rate for the euro against the U.S. dollar (EUR/USD) for the relevant trade date, as reported in Bloomberg. All sales reported above were made on a regulated stock market in the European Union. During the period above referred, no other transactions in Ordinary Shares were 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. 14.

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:	02/10/2026

SAN FAUSTIN S.A.

Signature:	SAN FAUSTIN S.A.
Name/Title:	/s/ Fernando J. Mantilla / Attorney-in-fact
Date:	02/10/2026

TECHINT HOLDINGS S.A R.L.

Signature:	TECHINT HOLDINGS S.A R.L.
Name/Title:	/s/ Fernando J. Mantilla / Attorney-in-fact
Date:	02/10/2026

Comments accompanying signature:

Pursuant to Rule 13d-1(k)(1), the undersigned joins in the filing of this Amendment No. 14 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. 14 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. 14 on his own behalf and on behalf of ROCCA & PARTNERS STICHTING ADMINISTRATIEKANTOOR AANDELEN SAN FAUSTIN and SAN FAUSTIN S.A.

FAQ

How many Tenaris (TS) shares does the reporting group currently own?

The reporting group beneficially owns 692,085,486 Tenaris ordinary shares. This holding represents 68.55% of the company’s outstanding ordinary shares, excluding treasury stock, giving the group significant influence over shareholder votes and key corporate decisions.

How did the controlling stake in Tenaris (TS) change in this Schedule 13D amendment?

The group’s beneficial ownership in Tenaris decreased from 69.66% to 68.55%. This change reflects market sales of ordinary shares by Techint Holdings, partly offset by Tenaris’s own share repurchases during the same period, slightly reducing the group’s ownership percentage.

How many Tenaris (TS) shares did Techint Holdings sell and over what period?

Techint Holdings sold a total of 18,919,701 Tenaris ordinary shares. These open‑market sales occurred between December 15, 2025 and February 6, 2026 under a non‑discretionary accelerated share disposal agreement with a European financial institution.

What share repurchases did Tenaris (TS) complete that affect this ownership calculation?

Tenaris repurchased 11,065,751 ordinary shares in the open market from December 15, 2025 to January 2, 2026. These buybacks were executed under the second tranche of a share buyback program publicly announced on November 2, 2025, partially offsetting the shareholder group’s sales.

Who are the reporting persons in this Tenaris (TS) Schedule 13D/A filing?

The reporting persons are Rocca & Partners Stichting Administratiekantoor Aandelen San Faustin (RP STAK), San Faustin S.A., and Techint Holdings S.A r.l.. RP STAK controls San Faustin, and San Faustin holds all shares of Techint Holdings, forming a coordinated ownership structure.

What percentage of Tenaris (TS) shares was used to calculate the ownership figures?

The percentages are based on 1,071,994,930 issued Tenaris ordinary shares, of which 62,328,172 shares were held as treasury stock as of January 2, 2026. This share count underlies the calculation of the reporting group’s 68.55% ownership stake.