GAS TRANSPORTER OF THE SOUTH INC

Foreign Filer Report • Dec 11, 2025

6-K 1 tgs.htm MATERIAL FACT Produced by EDGARsuite software, Advanced Computer Innovations, Inc., Copyright (C) 2008-2025 [PPXVPY40XJV0VA2H80ZZ]. www.edgarsuite.com

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

_______

FORM 6-K

Report of Foreign Issuer

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

the Securities and Exchange Act of 1934

For December 11, 2025

Commission file number: 1-13.396

Transportadora de Gas del Sur S.A.

Cecilia Grierson 355, piso 26

(1107), Capital Federal

Argentina

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

Form 20-F X Form 40-F

Indicate by check mark if registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): __

Indicate by check mark if registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): __

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to the Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes No X

If "Yes" is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b):

City of Buenos Aires, December 11, 2025.

E-NOTA-20251211-60901

Messrs.

Comisión Nacional de Valores (Argentine Securities and Exchange Commission)

Bolsas y Mercados Argentinos S.A. (Argentine Stock Exchanges and Markets)

Bolsa de Comercio de Buenos Aires (Buenos Aires Stock Exchange)

Gerencia Técnica y de Valores Negociables (Technical and Negotiable Securities Management)

A3 Mercados S.A. ( A3 Markets )

Re: Material Fact. Regular Transaction with Related Parties. Section 72 Act no. 26,831.

Dear Sirs,

I am writing to you in my capacity as Head of Market Relations of Transportadora de Gas del Sur S.A. (“tgs” or the “Company”), in order to report that in its meeting held today, the Board of Directors approved (i) the gas reference prices for SPOT purchases for Plant Thermal Reduction with Related Parties for the 2026 summer and winter periods (the “Reference Prices”) and (ii) the extension of the “Policy for LPG and Natural Gasoline/Raw Gasoline sale and resale operations” (the “Policy”), valid from January 1, 2026 until December 31, 2026.

Prior to approval of the Reference Prices and the Policy, tgs Audit Committee was asked to issue two reports in compliance with section 72 of Capital Markets Act no. 26,831.

On December 11, 2025, the Audit Committee concluded and informed the Board of Directors that the transactions with Related Parties carried out pursuant to and under the terms of the Reference Prices and the Policy can be deemed to be reasonably entered into on an arm’s length basis.

The Audit Committee’s reports are available for consultation by accredited shareholders if so desired, upon request via email at: direcciondelegales@tgs.com.ar .

Hernán Diego Flores Gómez

Head of Market Relations

SIGNATURES

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.

Transportadora de Gas del Sur S.A.

By:	/s/Alejandro M. Basso
Name:	Alejandro M. Basso
Title:	Chief Financial Officer and Services Vice President

By:	/s/Hernán D. Flores Gómez
Name:	Hernán Diego Flores Gómez
Title:	Legal Affairs Vice President

Date: December 11, 2025.