Situación de la Industria del Gas Natural en Argentina

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 August 13, 2025

Commission file number: 1-13.396

Transportadora de Gas del Sur S.A.

Cecilia Grierson 355, Twenty sixth Floor

(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):

Imagen 2 Imagen 12

INDEX

01 | ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS FOR THE

SIX-MONTH PERIOD ENDED JUNE 30, 2025

02 | CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

Statements of comprehensive income

Statements of financial position

Statements of changes in equity

Statements of cash flows

Notes to the condensed interim consolidated financial statements

TRANSPORTADORA DE GAS DEL SUR S.A.

FINANCIAL STATEMENTS AS OF JUNE 30, 2025 AND 2024

ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS FOR THE SIX-MONTH PERIOD ENDED JUNE 30, 2025

The following discussion of the financial condition and results of operations of Transportadora de Gas del Sur S.A. (“tgs” or “the Company”) should be read in conjunction with the Company's Consolidated Financial Statements as of June 30, 2025 and December 31, 2024, and for the six-month periods ended June 30, 2025 and 2024. These Condensed Interim Consolidated Financial Statements have been prepared in accordance with the provisions of International Accounting Standard 34 “Interim Financial Reporting” (“IAS 34”), issued by the International Accounting Standards Board (“IASB”), as adopted by the Comisión Nacional de Valores ("CNV") through the provisions of the New Text 2013 -Title IV, Chapter I, Section I, Article 1 – B.1.

The condensed interim consolidated financial statements of the Company for the six-month periods ended June 30, 2025, 2024, 2023, 2022 and 2021 have been subject to a limited review performed jointly by Price Waterhouse & Co. S.R.L. and Pistrelli, Henry Martin and Asociados S.A.

Effects of inflation

On December 3, 2018, Law No. 27,468 was enacted, sanctioned on November 15, 2018 by the National Argentine Congress. Among other measures, this law abolishes Presidential Decree No. 1,269/02 —amended by Presidential Decree No. 664/2003 — through which the controlling entities (among them the CNV) had been instructed not to accept inflation adjusted financial statements. On December 26, 2018, the CNV issued Resolution No. 777/2018, by virtue of which it instructs companies that offer their shares to the public to apply the financial statements restatement method to a stable currency in line with the provisions of IAS 29 “Financial Reporting in Hyperinflationary Economies”.

In accordance with such standards, the restatement of financial statements was restarted as from July 1, 2018. In line with the restatement method, non-currency assets and liabilities are restated by an overall price index issued by the Argentine Federation of Professional Councils in Economic Sciences (“Argentine Federation”) since their acquisition date or last inflation adjustment (March 1, 2003).

Likewise, comparative information included in the financial statements has also been restated, but this fact has not modified the decisions based on the financial information corresponding to those fiscal years.

For further information, see “Note 4. Significant Accounting Policies – d) Restatement to constant currency – Comparative Information” to the consolidated financial statements as of December 31, 2024.

Rounding

Certain figures included in this press release have been rounded for ease of presentation. Percentage figures included in this press release have not, in all cases, been calculated on the basis of such rounded figures but on the basis of such amounts prior to rounding. For this reason, percentage amounts in this report may vary from those obtained by performing the same calculations using the figures in our Financial Statements. Certain numerical figures shown as totals in some tables may not be an arithmetic aggregation of the figures that preceded them due to rounding.

1.Analysis of consolidated results of operations

The following table presents a summary of the consolidated results of operations for the six-month periods ended June 30, 2025 (“6M2025”) and June 30, 2024 (“6M2024”):

Activities of the Company in 6M2025 and 6M2024

Revenues

Total revenues for 6M2025 increased by Ps. 4,735 million compared to 6M2024, mainly as a result of the increase in revenues from the Natural Gas Transportation segment, partially offset by the decline in revenues from the Liquids Production and Commercialization and Midstream segments.

Natural Gas Transportation

During 6M2025 revenues from the Natural Gas Transportation business segment accounted for 45% of tgs total revenues (29% for 6M2024). Of the total revenues in this business segment, 80% (84% for 6M2024) corresponded to firm contracted capacity services.

On April 30, 2025, Resolution No. 256/2025 was published, establishing the framework for the Five-Year Tariff Review (“5YTR”) for the 2025–2030 period. It includes an initial tariff increase of 3.67% to be applied in 31 monthly installments, a regulated investment plan, and a new scheme for the periodic adjustment of tariffs.

Subsequently, in line with Decree No. 371/2025, the Secretariat of Energy introduced a monthly tariff update, replacing the previous semiannual scheme. This methodology was formalized by ENARGAS through Resolutions No. 350/2025 and No. 421/2025, which approved adjustments of 2.81% and 0.62%, respectively, also incorporating the increase corresponding to the 5YTR.

Thus, revenues from the Natural Gas Transportation segment during 6M2025 reached Ps. 312,439 million (Ps. 198,562 million in 6M2024). The increase of Ps. 113,877 million is due to the positive impact of transitional tariff increases received during 2024 and 2025 as well as those corresponding to the 5YTR framework.

It is worth noting that the operation of this business segment was partially affected by the climatic event that occurred at the Cerri Complex. However, there was no impact on revenues between March 7 and March 24, 2025. For further details, refer to Note 24 – Climatic Event at the General Cerri Complex in the Condensed Interim Consolidated Financial Statements.

On May 22, 2025, Energía Argentina S.A. (“ENARSA”) launched a national and international public tender for the expansion of the Perito Moreno Gas Pipeline (“GPM”), with the objective of increasing natural gas transportation capacity from Vaca Muerta by 14 MMm³/d. Bids were submitted on July 28, 2025, and the award is scheduled for October 13, 2025. Construction is expected to begin thereafter, with an estimated execution period of 18 months. This project was declared of national public interest

and falls under the private initiative regime, meaning that the awarded party will be responsible for the design, financing, construction, operation, and maintenance of the facilities.

On July 24, 2025, Decree No. 495/2025 was published in the Official Gazette, through which the National Executive Branch ordered the extension of the license granted to tgs by Decree No. 2458/1992, for an additional period of 20 years starting from December 28, 2027.

Liquids Production and Commercialization

During 6M2025, revenues for this business segment represented 34% of total revenues (52% for 6M2024).

Revenues from this business segment amounted to Ps. 238,415 million in 6M2025 (Ps. 119,520 million lower than in 6M2024). The negative effect was mainly due to the decrease in: (i) dispatched tons, (ii) the real exchange rate, and (iii) the international reference prices. These effects were partially offset by the positive variation in the prices of propane and butane sold in the domestic market.

Total volumes dispatched recorded a decrease of 21.9% or 118,490 tons compared to 6M2024.

The decrease in volumes sold was mainly due to the impact of the climatic event that occurred on March 7, 2025, when unprecedented heavy rainfall caused the overflow of the Saladillo García stream, which flooded the Cerri Complex and consequently halted the production of liquids and partially affected the natural gas transportation service.

Regarding the Liquids Production and Commercialization business segment, at the Cerri Complex, liquids production was interrupted from March 7, 2025, until the end of April. Operations gradually resumed thereafter, reaching normal production levels by early May. This process was made possible as infrastructure issues were resolved.

For more information see “Note 24 - Climatic Event at the General Cerri Complex" in the Condensed Interim Consolidated Financial Statements.

Midstream

Midstream revenues increased by Ps. 10,379 million in 6M2025 compared to the same period in 2024. This increase is due to higher natural gas transportation and conditioning services in Vaca Muerta, partially offset by the negative variation in the real exchange rate.

Net cost of sales and administrative and selling expenses

Net cost of sales, administrative and selling expenses corresponding to 6M2025 decreased by Ps. 11,300 million. This variation is mainly due to the decrease in the cost of natural gas processed at the Cerri Complex (primarily due to a decrease in price, measured in constant Argentine pesos, and the decline in RTP consumption). This effect was partially offset by the increase in depreciation, higher impairment of financial assets in the Natural Gas Transportation business segment, and repair and maintenance expenses.

The following table shows the main components of operating costs, administrative and selling expenses and their main variations for 6M2025 and 6M2024:

Other operating results, net

Other operating results, net experienced a loss of Ps. 32,426 million compared to Ps. 3,764 million in 6M2024. The negative variation is mainly due to the loss recorded for Ps. 33,573 million in expenses and provisions for impairment of materials and other PPE items related to the climatic event that occurred on March 7, 2025, at the General Cerri Complex.

Financial results

Financial results for 6M2025 experienced a negative effect of Ps. 95,520 million compared to the same period in 2024. The breakdown of the financial results is as follows:

This negative variation is mainly due to the lower positive financial results recorded by financial assets due to the decrease in yields obtained and the higher negative loss on net monetary position. These effects were partially offset by the higher net negative foreign exchange loss.

2. Liquidity

The Company’s primary sources and application of funds during 6M2025 and 6M2024 were the following:

During 6M2025, increase in cash and cash equivalents was negative by Ps. 42,869 million.

Cash Flows provided by operating activities amounted to Ps. 246,970 million. This cash flow is Ps. 29,740 million higher than that provided in 6M2024 due to the lower working capital, effect was partially offset by higher income tax paid.

Meanwhile, cash flow used in investing activities amounted to (Ps. 86,240) million, resulting in Ps. 47,262 million lower than the cash flow used in 6M2024 due to lower payments for the acquisition of PPE.

Finally, cash flow used in financing activities during 6M2025 amounted to (Ps. 203,599) million, while during 6M2024, cash flow used in financing activities amounted to Ps. 27,700 million. This increase was primarily due to the dividend payment approved on May 28, 2025, for Ps. 202,704 million. This effect was partially offset by the lower repayment, net of borrowings, of financial loans of Ps. 26,716 million.

3.Second Quarter 2025 (“2Q2025”) vs. Second quarter 2024 (“2Q2024”)

The following table presents a summary of the consolidated results of operations for the three-month periods ended June 30, 2025 (“2Q2025”) and June 30, 2024 (“2Q2024”):

During 2Q2025, the Company obtained comprehensive income of Ps. 40,278 million, compared to comprehensive income of Ps. 119,739 million obtained in the same period of 2024.

Total revenues for 2Q2025 decreased by Ps. 21,650 million compared to the same period of the previous year.

Revenues from the Natural Gas Transportation business segment in 2Q2025 decreased by Ps. 12,982 million, compared to 2Q2024. This negative variation resulted from the inability of the tariff increases granted to mitigate the adverse effects of inflation.

As for the Liquids Production and Commercialization business segment, revenues decreased by Ps. 25,216 million in 2Q2025, mainly due to the drop in (i) the the volumes dispatched, (ii) the exchange rate on sales denominated in US dollars and (iii) the international reference prices. These effects were partially offset by the increase in the price of ethane.

With respect to the total volumes dispatched from the Cerri Complex, which decreased by 15% or 38,523 tons, the table included below shows the volumes dispatched by market and product and revenues by market:

The Midstream business segment reported an increase of Ps. 16,548 million, mainly explained by greater natural gas transportation and conditioning services in Vaca Muerta. This effect was partially offset by the lower exchange rate measured in constant currency.

Cost of sales and administrative and selling expenses for 2Q2025 amounted to Ps. 207,080 million (compared to Ps. 189,635 million in 2Q2024), an increase of Ps. 17,445 million. This variation is mainly due to higher: (i) depreciations; (ii) impairment of financial assets related to a customer in the Natural Gas Transportation Segment, and (iii) labor costs. These effects were partially offset by the lower cost of natural gas processed at the Cerri Complex, mainly due to reduced consumption.

The following table shows the main components of operating costs, administrative and selling expenses and their main variations for 2Q2025 and 2Q2024:

In 2Q2025, financial results recorded a negative variation of Ps. 76,660 million, compared to those registered in the 2024 period. This variation is mainly due to a lower positive result generated by financial assets and a higher negative exchange rate difference driven by the greater variation in the exchange rate during 2Q2025.

Other operating results, net recorded a negative variation of Ps. 15,265 million, mainly due to higher charges incurred as a result of the Weather Event.

4. Consolidated Financial Position Summary

Summary of the consolidated financial position information as of June 30, 2025 and December 31, 2024, 2023, 2022 and 2021:

5. Consolidated Comprehensive Income Summary

Summary of the consolidated comprehensive income information for the six-month periods ended June 30, 2025, 2024, 2023, 2022 and 2021:

6. Consolidated Cash Flow Summary

Summary of the consolidated cash flow information for the six-month periods ended June 30, 2025, 2024, 2023, 2022 and 2021:

7. Statistical Data (Physical units)

8. Comparative Ratios

9. tgs share market value in Buenos Aires Stock Exchange at closing of last business day (in Argentine Pesos per share)

	2025	2024	2023	2022	2021
January	6,750.00	3,798.35	830.00	225.00	151.65
February	6,060.00	2,779.95	834.55	232.60	138.85
March	6,950.00	3,279.35	824.75	262.80	139.10
April	6,040.00	3,862.20	1,037.90	262.35	139.35
May	6,750.00	4,900.00	1,201.15	282.15	152.20
June	6,260.00	5,164.75	1,414.60	260.50	156.65
July	7,820.00	4,550.00	1,362.95	349.65	159.05
August		4,995.00	1,980.00	393.50	193.25
September		4,550.00	1,700.00	462.50	192.00
October		5,300.00	1,751.70	536.75	217.30
November		6,600.00	2,410.00	650.00	184.55
December		7,020.00	2,956.15	812.90	181.10

10. Outlook

The future of natural gas as an essential fuel for the country's energy matrix is consolidated year after year, which will make Argentina a sustainable country with high growth. We have consolidated ourselves as an integrated service provider in the hydrocarbon industry.

Our strategy aims to position ourselves in a leading role, carrying out vital undertakings for the future of the country, thus consolidating the growth strategy with a leap of magnitude. With this objective,

we are adopting an innovative vision, seeking new business opportunities for our clients with a focus on Vaca Muerta.

Continuing our growth plan in the area, we expect to keep developing business opportunities that allow us to generate value for producers in the Vaca Muerta area and enhance Argentina's energy development.

In the Liquids Production and Commercialization Segment, the strategy will be aimed at optimizing the production mix that allows prioritizing those products and distribution channels that provide higher margins, and to maximizing access to the RTP at reasonable costs. For this, it will be very important to be efficient in the management of our assets, ensuring a coordinated, safe and efficient operation.

In financial terms, and given the aforementioned facts, we will continue to prudently manage our funds in order to preserve our shareholders´ value given the volatile macroeconomic context in which our activities will be carried out.

As regards their daily operations, tgs will remain committed to the continuous improvement of each of its processes in order to optimize resource utilization and thereby reduce operating costs. To this end, the Company aims to maintain the levels of operational reliability that represent a key commitment to its customers. Accordingly, the Company will continue implementing various initiatives, such as the standardization and systematization of risk management across pipelines, compressor plants, and processing facilities. Finally, we will deepen training initiatives for the staff for technical and management training resources.

Autonomous City of Buenos Aires, August 5, 2025.

Luis Fallo

Chairman

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

1.BUSINESS DESCRIPTION

Business Overview

Transportadora de Gas del Sur S.A. (“tgs” or the “Company”) is one of the companies created as a result of the privatization of Gas del Estado S.E. (“GdE”). tgs commenced operations on December 28, 1992 and it is mainly engaged in the Transportation of Natural Gas, and Production and Commercialization of natural gas Liquids (“Liquids”). TGS’s pipeline system connects major natural gas fields in southern and western Argentina with natural gas distributors and industries in those areas and in the greater Buenos Aires area. The natural gas transportation license to operate this system was exclusively granted to tgs for a period of thirty-five years (“the License”). tgs is entitled to a one-time extension of ten years provided that it has essentially met the obligations imposed by the License and by Ente Nacional Regulador del Gas (National Gas Regulatory Body or “ENARGAS”). The General Cerri Gas Processing Complex (the “Cerri Complex”), where TGS processes natural gas to obtain liquids, was transferred from GdE along with the gas transmission assets. tgs also provides midstream services, which mainly consist of gas treatment, removal of impurities from the natural gas stream, gas compression, wellhead gas gathering and pipeline construction, operation and maintenance services. In addition, telecommunications services are provided through the subsidiary Telcosur S.A. (“Telcosur”). These services consist of data transmission services through a network of terrestrial and digital radio relay.

Subsequently, the corporate purpose of the Company was modified to incorporate the development of complementary activities, incidental, linked and / or derived from natural gas transportation, such as the generation and commercialization of electric power and the provision of other services for the hydrocarbon sector in general.

Major Shareholders

As of December 31, 2024, tgs´ controlling shareholder Compañía de Inversiones de Energía S.A. (“CIESA”), held 51% of the common stock of the company, the National Social Security Administration (“ANSES”) held 24% and the remaining 25% was held by the investing public on the Bolsa de Comercio de Buenos Aires and the New York Stock Exchange (“NYSE”) (tgs had 5.25% of the shares in the portfolio).

On April 30, 2025, the Ordinary, Extraordinary and Special General Shareholders' Meeting approved the reduction of the Company's share capital, in accordance with the provisions of Note 20 – Common stock and Dividends. Following this decision, the Company´s share capital was structured as follows: CIESA holds 53.83%, ANSES holds 25.33% and public offering hold the remaining 20.84%.

CIESA is under joint control of Pampa Energía S.A. (“Pampa Energía”) with 50% and Grupo Inversor Petroquímica S.L. (“GIP”) and PCT L.L.C. with the remaining 50%.

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

The following table shows the organizational structure, shareholders and related parties of tgs as of June 30, 2025:

Dedicated Branch 1

On May 22, 2025, Energía Argentina S.A. (“ENARSA”) launched a national and international public bidding process for the expansion of the Perito Moreno Gas Pipeline (“GPM”), with the objective of increasing the natural gas transportation capacity from Vaca Muerta by 14 MMm³/d. Bids were submitted on July 28, 2025, with tgs being the sole bidder, and the contract award is scheduled for October 13, 2025. Construction work is expected to begin later and has an estimated execution period of 18 months. This project was declared to be of national public interest and falls under the private initiative regime, which means that the successful bidder will be responsible for the design, financing, construction, operation, and maintenance of the facilities.

Detailed data reflecting subsidiary control as of June 30, 2025, is as follows:

For consolidation purposes for the six-month period ended June 30, 2025, the financial statements of Telcosur have been used at those dates.

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

Economic context

The Company operates in a complex economic environment whose main variables have recently had strong volatility as a result of political and economic events at the national level.

During the first semester of 2025, the Argentine economy showed signs of recovery in a context of consolidation of economic policies aimed at stabilization and structural reforms.

The accumulated inflation as of June 30, 2025 was 15.1%, with a monthly deceleration compared to the early months of the year. In terms of economic activity, Gross Domestic Product (GDP) grew by 5.8% in the first quarter, with projections indicating an acceleration in the second quarter.

On the international front, the Government reached an extended facilities agreement with the International Monetary Fund (IMF) for US$ 20 billion, with a 48-month term. This agreement, along with additional financing from multilateral organizations totaling USD 3.1 billion, supports the next phase of the economic program, focused on stabilization and structural reforms.

This phase, announced on April 11, mainly includes: (i) the flexibilization of the exchange rate regime where the dollar exchange rate in the Free Exchange Market (MLC) can fluctuate within a moving band between $1,000 and $1,400, with the limits expanding at a rate of 1% per month, (ii) the elimination of the blend dollar scheme, (iii) the removal of exchange restrictions for individuals, (iv) authorization of the distribution of profits to foreign shareholders starting from the fiscal years beginning in 2025 (i.e., payments allowed from 2026 onward), and (v) the deadlines for the payment of foreign trade operations are relaxed.

The relaxations for the payment of foreign trade operations include:

·The 30-day waiting period from the customs entry of goods is eliminated.

·The deadline for the payment of services in cash from their provision is eliminated.

·The payment of services to related companies is allowed starting from 90 days after their provision.

·Small and medium-sized enterprises can pay from the dispatch of goods at the port of origin.

·Payments for the importation of capital goods are relaxed, now allowing a 30% advance payment.

Additionally, on April 30, 2025, the BCRA approved a new issue of Bonds for the Reconstruction of a Free Argentina (BOPREAL) for up to USD 3 billion, intended to regularize private sector liabilities for unpaid dividends. The bonds, denominated in dollars, accrue an annual rate of 3% and mature in October 2028.

Regarding monetary policy, the nominal anchor is reinforced by perfecting the monetary policy framework in which there is no issuance of pesos by the BCRA for financing the fiscal deficit or for the remuneration of its monetary liabilities.

Furthermore, on the international front, the United States government has taken a series of economic measures that marked a significant shift in trade and fiscal policy. Specifically, on April 2, 2025, President Trump announced that the United States would impose a 10% tariff on all countries, effective from April 5, 2025, as well as a higher and customized reciprocal tariff for those countries with which the United States maintains the largest trade deficits. Although certain energy products have been excluded, the effect of these measures on economic growth and global trade remains uncertain and could disrupt international trade flows and increase operational costs for companies that rely on international supply chains.

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

Likewise, the Company's management permanently monitors the evolution of the variables that affect its business, to define its course of action and identify the potential impacts on its equity and financial situation. The reforms proposed by the new government began their legislative discussion process. It is not possible to predict at this time its evolution or new measures that could be announced. Likewise, the Company cannot guarantee that the aforementioned macroeconomic difficulties or the adoption of new measures by the Argentine Government to control inflation may affect its operations and financial situation.

2.CONSOLIDATED FINANCIAL STATEMENTS

tgs presents its Condensed Interim Consolidated Financial Statements for the six-month periods ended June 30, 2025 and 2024 preceding its Interim Condensed Separate Financial Statements in accordance with Title IV, Chapter I, Section I, article 1.b.1 of CNV´s regulations requiring the use of International Accounting Standard 34 (“IAS 34”) issued by the International Accounting Standards Board (“IASB”) adopted by the CNV through NT 2013 (the “Rules”).

References in these financial statements to "tgs" or the "Company" refer to Transportadora de Gas del Sur S.A. and its consolidated subsidiary Telcosur.

These Condensed Interim Consolidated Financial Statements, which were approved and authorized for issuance by the Board of Directors on August 5, 2025, do not include all the information and disclosures required for annual Financial Statements, and should be read in conjunction with tgs’ annual Financial Statements as of December 31, 2024, issued on February 27, 2025.

3.BASIS OF PRESENTATION

The Comisión Nacional de Valores (“CNV”), as set forth by the Title IV, Chapter III, Article 1 of the Rules has provided that listed companies must submit their condensed consolidated financial statements by applying Technical Resolution No. 26 of the Argentine Federation of Professional Councils of Economic Sciences ("FACPCE"), and its amendments, which adopts the International Financial Reporting Standards ("IFRS Accounting Standards") issued by the IASB, its amendments and circulars for the adoption of IFRS Accounting Standards that the FACPCE dictates in accordance with the provisions of that Technical Resolution.

In light of the matters discussed in the preceding paragraph, the Company has prepared these Condensed Interim Consolidated Financial Statements in accordance with the accounting framework established by the CNV, which is based on the application of IFRS Accounting Standards, specifically International Accounting Standard No. 34 'Interim Financial Reporting' (IAS 34)."

The subsidiary that reflects tgs's corporate group as of June 30, 2025 is Telcosur.

For consolidation purposes for the six-month periods ended June 30, 2025 and 2024, Telcosur's financial statements have been used at those dates.

The Condensed Interim Consolidated Financial Statements for the six-month periods ended June 30, 2025 and 2024 have not been audited. The Management of the Company estimates that they include all the necessary adjustments to reasonably present the results of each period in accordance with the accounting framework applied. The results of the six-month periods ended June 30, 2025 and 2024, do not necessarily reflect the proportion of the results of the Company for the full fiscal year.

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

Functional and presentation currency

The Condensed Interim Consolidated Financial Statements are stated in thousands of Argentine pesos (“Ps.”), the functional currency of the Company and its subsidiary.

Restatement to current currency

The Condensed Interim Consolidated Financial Statements as of June 30, 2025, including comparative figures, have been restated to take into account changes in the general purchasing power of the Company's functional currency in accordance with IAS 29 "Financial information in hyperinflationary economies” ("IAS 29") and in General Resolution No. 777/2018 of the CNV, using the BCRA's Market Expectations Survey for the last month of the period, since, at the date of closing the Company's accounting books, the INDEC index was not yet available. As a result, the financial statements are expressed in the unit of measurement current at the end of the reporting period.

The variation in the consumer price index (“CPI”) for the restatement of these Condensed Interim Consolidated Financial Statements was estimated at 15.36% and 79.81% for the six-month periods ended June 30, 2025 and 2024, respectively.

Information comparability

The balances as of December 31, 2024 and June 30, 2024 that are disclosed for comparative purposes were restated in accordance with IAS 29, as mentioned above.

4.SIGNIFICANT ACCOUNTING POLICIES

The accounting policies applied to these Condensed Interim Consolidated Financial Statements are consistent with those used in the financial statements for the last financial year prepared under IFRS Accounting Standards, which ended on December 31, 2024.

New accounting policies, amendments and interpretations issued by the IASB that have been adopted by the Company.

The Company has applied the following standards and/or amendments for the first time as of January 1, 2025:

·Amendments to IAS 21 – Lack of Exchangeability of Currencies.

The new accounting standards, amendments and interpretations issued by the IASB that became effective as of January 1, 2025, have not had an impact on the Company's condensed interim consolidated financial statements.

New standards, amendments, and interpretations issued but not yet effective for annual periods beginning on or after January 1, 2025, and not early adopted:

The CNV, through RG 972/2023, amended its Consolidated Text, establishing that early applications of IFRSs and/or their amendments are not admissible, except when specifically allowed at the time of adoption.

·IFRS Accounting Standard 18 – Presentation and Disclosure in Financial Statements

·IFRS Accounting Standard 19 – Subsidiaries without Public Accountability

·Amendments to IFRS Accounting Standards 9 and 7 – Classification and measurement of financial instruments

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

·Annual improvements to IFRS Accounting Standards – Volume 11 (includes IFRS Accounting Standards 1, 7, 9 and 10, and IAS 7)

5.FINANCIAL RISK MANAGEMENT

The Company’s activities and the market in which it operates expose it to a series of financial risks: market risk (including foreign exchange risk, interest rate risk, and commodity price risk), credit risk and liquidity risk.

There were no significant changes since the last annual closing in the risk management policies.

Due to the main impacts of the described situation detailed in Note 1 to these condensed interim consolidated financial statements, the Company has implemented a series of measures that will mitigate its impact. In this sense, the Company's Management constantly monitors the evolution of the situations that affect its business, to determine the possible actions to be taken and to identify the possible impacts on its equity and financial position. The Company's Condensed Interim Consolidated Financial Statements should be read under the light of these circumstances.

6.CRITICAL ACCOUNTING ESTIMATES

The preparation of financial statements in conformity with professional accounting standards requires the Company to make accounting estimates that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period.

The making of such estimates involves tgs using assumptions and presumptions that are based on a number of factors, including past trends, events known at the date of issuance of these financial statements, and expectations of future events and their outcomes.

In the Natural Gas Transportation segment, as mentioned in Note 19 to these Condensed Interim Consolidated Financial Statements, the Company concluded the Five-Year Tariff Review process (“5YTR”) after ENARGAS issued Resolution No. 256/2025 (the “Resolution 256”). This resolution not only defined the initial tariff increase but also the investment and expenditure plan for the period 2025-2030.

In this regard, the Company considered scenarios taking into account the current tariff regime and new estimates of macroeconomic variables. Likewise, the Company updated its assessment of impairment indicators in accordance with IAS 36 as of June 30, 2025.

Additionally, as mentioned in "Note 24 – Climate Event at Cerri Complex", following the occurrence of the weather event mentioned therein, the Management of the Company evaluated the existence of impairment indicators.

The conclusion of these evaluations was that no new factors were identified that negatively affect the premises underlying the recoverable value of the assets included within PPE, compared to the last evaluation carried out as of December 31, 2024.

Based on the above, the Company did not identify the need to record any impairment of the PPE amounts, other than what is disclosed in Note 24.

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

7.SUPPLEMENTAL CASH FLOW INFORMATION

For purposes of the consolidated statement of cash flows, the Company considers all highly liquid temporary investments with an original maturity of three months or less at the time of purchase to be cash equivalents. The Cash Flow Statement has been prepared using the indirect method, which requires a series of adjustments to reconcile net income for the period to net cash flows from operating activities.

Non-cash investing and financing activities for the six-month periods ended June 30, 2025 and 2024 are presented below:

Note 14 to these Condensed Interim Consolidated Financial Statements includes a reconciliation between the opening and closing balance of the financial liabilities arising from financing activities.

8.CONSOLIDATED BUSINESS SEGMENT INFORMATION

IFRS Accounting standard 8 “Operating Segments” requires an entity to report financial and descriptive information about its reportable segments, which are operating segments or aggregations of operating segments that meet specified criteria. The business segments are reported in a manner consistent with the information reviewed by the Company's Board of Directors, which is the decision-making body of the Company.

For management purposes, tgs is organized into four business segments based on the products and services it offers: (i) Natural Gas Transportation Services, subject to ENARGAS regulations, (ii) Liquids Production and Commercialization, (iii) Midstream and (iv) Telecommunications. These last three business segments are not regulated by ENARGAS. The production and commercialization of Liquefied Petroleum Gas (“LPG”) are subject to regulations established by the Secretariat of Energy.

Detailed information on each business segment for the six-month periods ended June 30, 2025 and 2024 is disclosed below:

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

The breakdown of revenues from sales of goods and services by market and opportunity for the six-month periods ended June 30, 2025 and 2024 is as follows:

9.DETAIL OF SIGNIFICANT STATEMENT OF FINANCIAL POSITION AND STATEMENT OF COMPREHENSIVE INCOME CAPTIONS

a) Other receivables

b) Trade receivables

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

The movement of the impairment of financial assets is as follows:

c) Cash and cash equivalents

d) Contract liabilities

e) Other payables

f) Taxes payables

English translation of the original prepared in Spanish for publication in Argentina

TRANSPORTADORA DE GAS DEL SUR S.A.

NOTES TO THE CONDENSED INTERIM CONSOLIDATED FINANCIAL STATEMENTS

AS OF JUNE 30, 2025 AND COMPARATIVE INFORMATION

(Stated in thousands of pesos as described in Note 3, unless otherwise stated)

_____________________________________________________________________________________________________

g) Trade payables

h) Revenues

i) Net cost of sales

Amount in US$	24,000,000
Interest rate	1.5% annual
Amortization date	July 28, 2025
Interest payment frequency	To the expiration
Guarantee	Fixed term in foreign currency⁽¹⁾

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