Preparing the consolidated financial statements requires that the Company make future judgments and estimates, apply significant accounting judgments and make assumptions that affect the application of accounting policies and the figures for assets and liabilities, revenue and expenses.

The estimates and judgments used in preparing the consolidated financial statements are constantly evaluated and are based on the historical experience and other factors considered to be fair in accordance with current circumstances. Future profit (loss) may differ from the estimates and evaluations made as of the date of preparation of these consolidated financial statements.

Below are the significant judgments other than those involving estimates (Note 3.2) that Management made and that have a material impact on the figures recognized in the consolidated financial statements.

The Company is subject to several claims, trials and other legal proceedings that arose during the ordinary course of business. The Company’s liabilities with respect to such claims, trials and other legal proceedings cannot be estimated with an absolute certainty. Therefore, the Company periodically reviews each contingency status and assesses the potential liability, employing the criteria mentioned in Note 22.3; hence, Management makes estimates mainly with the legal counsel’s assistance.

Contingencies include pending lawsuits for potential damage or third-party claims in the Company’s ordinary course of business and claims from disputes related to the interpretation of applicable legislation.

The costs incurred in limiting, neutralizing or preventing environmental pollution are capitalized only if at least one of the following conditions is met: (i) these costs are related to security improvements; (ii) environmental pollution risk is prevented or limited; or (iii) the costs incurred in preparing assets for sale and the carrying amount (which considers these costs) of these assets does not exceed the related recovery value.

The liabilities related to future remediation costs are booked when, based on environmental assessments, the likelihood of occurrence of these liabilities is high and costs may be reasonably estimated. The actual recognition and amount of these provisions is generally based on the commitments acquired by the Company to realize them, such as an approved remediation plan or the sale or disposal of an asset. The provision is recognized on the basis that the future remediation commitment will be required.

The Company measures liabilities based on the best estimate of the present value of future costs using the information currently available and by applying current environmental laws and regulations and the Company’s existing environmental policies.

The Company determines that it has acquired a business when the acquired set of activities and assets include an input and a substantive process that together significantly contribute to the ability to create an output. The acquired process is considered substantive if it is critical to the ability to continue producing outputs, and the inputs acquired include an organized workforce with necessary skills, knowledge or experience to perform that processes or else it significantly contributes to the ability to produce outputs and is considered unique or scarce or cannot be replaced without significant cost, effort or delay in the ability to continue producing outputs. In cases where an oil and gas property acquisition transaction does not compliance the above conditions, the Company considers that it must be recognized as an asset acquisition.

When the Company determines that it has acquired a business, to determine the fair value of identifiable assets, the Company uses the valuation approach that is most representative for each asset. These methods are the (i) income approach through indirect cash flows (net present value of expected future cash flows) or through the multi-period excess earnings method; (ii) cost approach (replacement value of the asset adjusted by loss due to physical impairment, functional and economic obsolescence); and (iii) market approach through a comparable transaction method.

Also, to determine the fair value of liabilities assumed, the Company considers the likelihood of cash outflows that will be required for each contingency and calculates the estimates with the legal counsel’s assistance based on available information and the litigation and resolution/settlement strategy.

Management significant judgment is required to choose the approach to be used and estimate future cash flows. Actual cash flows and values may differ significantly from expected future cash flows and the related values obtained through the aforementioned valuation techniques.

As detailed in Note 1.2.2 and 32, during the year ended December 31, 2025 the Company recognized the acquisition of Vista Lach as a business combination (“Business Combination”).

The Company assesses whether it has joint control on an arrangement, analyzing the activities and decisions about these relevant activities that require unanimous consent. The Company determined that the relevant activities for joint arrangements are those related to operating decisions, including the approval of the annual budget and the approval of service suppliers. The considerations made to assess joint control are the same as those needed to determine control on investments as established in Note 2.3.1.

The functional currency of the Company and its subsidiaries is the USD (Note 2.4.5.1), the currency of the primary economic context in entity operates. To determine the functional currency, the Company makes judgments. The Company reconsiders the functional currency in the event of a change in conditions that may determine the primary economic context.

Goodwill is reviewed annually for impairment or more frequently if there are events or changes in circumstances showing that the recoverable amount of the CGU related to goodwill should be analyzed. Whether goodwill is impaired is assessed by considering the rec

erable amount of the CGUs to which it is allocated. Impairment is recognized when the recoverable amount of the CGU is lower than its carrying amount (including goodwill).

The assessment of whether goodwill of a CGU or group of CGUs is impaired involves Management estimates on highly uncertain matters, including the assessment of the appropriate group of CGUs for goodwill impairment testing. The Company supervises goodwill for internal management purposes based on its only business segment.

To assess whether a CGU may be impaired, internal and external sources of information are analyzed, which could indicate thar that the book value of an asset or CGU may not be recovered. If any indication of impairment exists, the Company estimates the recoverable amount of the asset or CGU.

The recoverable amount of a CGU is the highest of (i) its fair value less costs of disposal, and (ii) its value in use. When the carrying amount of a CGU exceeds its recoverable amount, the CGU is deemed impaired, and it is reduced to its recoverable amount. Due to the nature of the Company’s activities, the information on the fair value less costs of disposal of an asset or CGU is usually difficult to obtain unless negotiations are underway with potential buyers or similar transactions. Consequently, unless otherwise stated, the recoverable amount used in impairment testing is the value in use.

As the initial step in drafting these plans, the Company establishes different assumptions which consider existing prices, the balance between global supply and demand of crude oil and natural gas. Upon assessing the value in use, estimated future cash flows are adjusted to consider the specific risks of the CGUs and are discounted at present value using a discount rate that reflects the current market assessments of the time value of money.

The Company assesses whether there is an indication that previously recognized impairment losses have reversed or decreased as of each reporting date. A previously recognized impairment loss is reversed only if here has been a change in the estimates used in determining the recoverable amount of the asset.

The assessment of whether an asset is impaired and to which extent involves Company estimates highly uncertain issues such discount rates, reserves and resources and commodity future prices. Actual cash flows and values may differ significantly from expected future cash flows and related amounts obtained using discount techniques, which could create major changes in the accounting values of the Group’s assets.

However, as of December 31, 2025, the Company identified trigger events related to the CGU in Mexico, as a consequence of the event described in Note 1.1 regarding of irrevocable relinquishment of the entire

CS-01

Area. Therefore, the Company recorded an impairment for the total assets of 38,252, which includes 38,229 related to “Property, plant and equipment” and 23 related to “Other intangible assets” (Note 12 and 13).

However, as of December 31, 2024, the Company identified reversal of trigger events related to the CGU in Mexico, mainly resulting from the recovery of the local price of natural gas. Therefore, the Company performed an impairment test and recorded a reversal of impairment of 4,207 (Note 12).

As of December 31, 2023, the Company identified trigger events related to the decline in the international price of crude oil in Mexico and local price of natural gas in Argentina. Therefore, the Company performed an impairment testing and recorded an impairment of 22,906 related to the CGU in Mexico and 1,679 related to the CGU in Argentina.

(i)

Discount rates:

Discount rates represent the present market value of the Company’s specific risks considering the time value of money and the individual risks of the underlying assets that have not been considered in cash flow estimates. The discount rate is calculated based on the Company’s specific circumstances and is derived from the weighted average cost of capital (“WACC”) with the proper adjustments to reflect risks and determine the rate before taxes. The income tax rate used is the tax rate effective in Argentina and Mexico standing at 35% and 30%, respectively. The WACC considers the cost of debt and cost of capital and considered public market data of certain companies deemed comparable (“comparable companies”) based on the industry, region and main activity.

The Company considered discounts for crude oil prices based on the quality of the crude oil produced in each CGU. The dynamics of the domestic crude oil and liquid fuels markets in Argentina and Mexico are also considered. The changes in Brent and Maya prices was estimated using the average market analysis forecasts.

To forecast the local price of natural gas used the average price received from gas sales in each CGU. Natural gas prices are adjusted by the calorific value of gas produced in each CGU.

(iii)

Production and reserve volumes

: the production level and the reserves is based on the reports certificated by external consultants and different risk factors were also applied to determine the expected value of each type of reserve (Note 33).

Regarding the assessment of the value in use as of December 31, 2025, and 2024, the Company considers that there are no reasonably possible changes in any of the abovementioned main assumptions that may cause the carrying amount of any CGU to decrease its recoverable amount, except for the following:

The aforementioned sensitivity analysis may not be representative of the actual change in the carrying amount because it is unlikely that the change in the assumptions would occur in isolation as some assumptions may be correlated.

As of December 31, 2025, and 2024, the net carrying amount of property, plant and equipment, other intangible assets and

right-of-use

assets is disclosed in Notes 12, 13 and 14, respectively.

The Company recognizes a current income tax liability as of every

year-end,

calculated according to effective laws enacted by the related tax authorities and, if necessary, provisions are recognized based on the amounts payable to tax authorities. However, there are some transactions and calculations which tax assessment is uncertain as sometimes tax regulations are subject to Company interpretation.

When tax treatments are uncertain and it is probable that a tax authority will accept the tax treatment afforded by the Company, income tax is recognized according to their calculations and interpretations. If it is not considered likely, the uncertainty is shown using the most likely amount method or the expected value method depending on the method that best predicts the resolution to the uncertainty.

Deferred tax assets are reviewed as of each reporting date and are amended according to the probability that the tax base allow the total or partial recovery of these assets. Upon assessing the recognition of deferred tax assets, the Company considers whether it is probable that some or all assets are not realized, which depends on the generation of future taxable profit in the periods in which these temporary differences become deductible. To this end, the Company considers the expected reversal of deferred tax liabilities, future taxable profit projections and tax planning strategies.

The assumptions on the generation of future taxable profit depend on the Company estimates of future cash flows, which are affected by sales and production volumes; crude oil and natural gas prices; operating costs; well plugging and abandonment costs; capital expenses; and the judgment on the application of tax laws effective in each jurisdiction.

Insofar as future cash flows and taxable profit substantially differ from the Group’s estimates, the Group’s capacity to realize net deferred tax assets booked at reporting date may be affected. Moreover, future changes in the tax laws in the jurisdictions in which the Group operates may hinder its capacity to obtain tax deductions in future periods.

Well plugging and abandonment at the end of the exploitation concession term requires that Company Management calculate the number of wells, the long-term costs of abandonment and the remaining time until abandonment. The technological, cost, policy, environment and safety issues change constantly and may give rise to differences between actual costs and future estimates.

Oil and gas items of property, plant and equipment are depreciated using the UDP method over total proved reserves (developed and not developed as applicable). Proved oil and gas reserves are those quantities which by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be economically producible from a given date forward, from known reservoirs, and under existing economic conditions, operating methods, and government regulations.

The useful life of each property, plant and equipment asset is assessed at least annually considering the physical limitations of the goods and the assessments of the economically recoverable reserves in the field in which the asset is located.

There are several uncertainties in the estimate of proved reserves and future production plans, development costs and prices, including several factors that are beyond the Company’s control. In estimating reserves involves a certain degree of uncertainty and depend on the quality of the engineering and geological data available as of the estimate date and their interpretation and judgment.

Reserve estimates are adjusted by changes in the assessment criteria or at least annually. These reserves are based on internal estimates of reserves engineers, certified annually by independent reserve engineering consultant.

The Company uses the information obtained from the reserve calculation in determining the depreciation of assets used in oil and gas areas, and in assessing their recoverability (Note 3.2.1, 3.2.2, 12 and 33).

The fair value measurement is complex due to the use of work performed by independent reserve engineers, the adoption of a discounted cash flow method, the assessment of the key assumptions applied, including discount rates, production profiles, reserves, and future commodity prices. These judgments are based on information available at the acquisition date and may involve a significant degree of estimation (see Note 1.2.2, 2.4.18 and 32).

The fair value estimate of share-based payments requires the determination of the most appropriate valuation model, which depends on the terms and conditions of the award. This estimate also requires the assessment of the most appropriate input for the valuation model, including the remaining life of stock options, and the shares volatility.

To measure the fair value of share-based payments at grant date, the Company employs the Black & Scholes model. The carrying amount, hypotheses and models used in estimating the fair value of transactions involving share-based payments are disclosed in Note 31.

On February 23, 2023, the Company through its subsidiary Vista Energy Argentina S.A.U. (“Vista Argentina”), entered into an agreement with Tango for the following concessions of the Neuquina Basin, Argentina (the “Initial Transaction”): (i) the Entre Lomas upstream concession located in the Province of Neuquén; (ii) Entre Lomas, Jarilla Quemada, Charco del Palenque, Jagüel de los Machos and 25 de Mayo-Medanito S.E upstream concessions located in the Province of Río Negro (jointly, the “Exploitation Concessions”); (iii) the Entre Lomas and Jarilla Quemada gas transportation concession located in the Province of Río Negro, and (iv) the 25 de Mayo-Medanito S.E. Crude oil transportation concession located in the Province of Río Negro (jointly with the Exploitation concessions the “Concessions”).

Under the terms of the Initial transaction, during the Operating Period, Vista Argentina maintains the ownership of the Concessions, and Tango: (i) pays 26,468 in cash (10,000 on February 15, 2023, (“Signature Date”) and 10,734 and 5,734 in March 2024 and 2025, respectively); (ii) will operate the Concessions on an

as is where is

basis, and (iii) pays 100% of Vista’s share capex and all operating cost, including royalties and taxes related.

Vista Argentina maintains the right to explore and develop the Vaca Muerta formation in the exploitation concessions, and that it may obtain one or more independent and separate unconventional concessions to develop such resources.

In addition, the Parties signed Natural gas processing and sales agreements whereby Tango undertakes to provide Vista Argentina with certain additional volumes of Natural gas, and to process and deliver the Natural gas applicable to Vista Argentina.

This initial consideration is related to the committed funds and the initial credit recognized, which is equivalent to the discounted value of the agreed-upon volumes of crude oil, natural gas and LPG to be received during the Operating Period. For the valuation of receivables, the Company has estimated the terms and costs of supplying these volumes and the discount rate applicable.

On August 28, 2025, the Parties agreed to certain amendments to the Initial Transaction, including an adjustment to the crude oil production percentage retained by Vista, which was revised to 20%, and an extension to the schedule, with the Final Closing Date set for February 28, 2029, and the Long-Stop Date for March 31, 2029.

For the years ended December 31, 2025, 2024 and 2023, the Company recognized 29,016, 33,570 and 27,539 in the consolidated statement of profit or loss under “Other

non-cash

costs related to the transfer of conventional assets”, mainly related to the cost related for supplying the volumes of crude oil, natural gas and LPG by Tango under the agreement, which were discounted from the initial credit recognized for the transaction.

Likewise, for the year ended December 31, 2023, as a consequence of the Initial Transaction, the Company recognized a gain of 89,659 in “Other operating income” under “Gain related to transfer of conventional assets” (Note 9.1) resulting from the difference between the initial consideration and the residual value deletion of net assets included in the Transaction.