Note 33. Supplementary information on oil and gas activities (unaudited)

The following information on crude oil and natural gas activities was prepared according to the method established in ASC 932 “Extractive Activities – Oil & gas”, amended by ASU 2010 - 03 “Oil and Gas Reserve Estimation and Disclosure,” published by the Financial Accounting Standard Board (“FASB”) in January 2010 to align current estimation and disclosure requirements with the requirements in the final rules and interpretations issued by the Security and Exchange Commission (“SEC”), published on December 31, 2008. This information includes the Company’s Crude oil and Natural gas production activities in Argentina and Mexico.

Costs incurred

The following table shows capitalized costs and expenses incurred in the years ended December 31, 2025, 2024 and 2023, based on the following considerations:

 

 

 

 

 

 

 

Capitalized cost

The following table shows capitalized costs during the years ended December 31, 2025, 2024, and 2023, for proved and unproved crude oil and natural gas reserves, and accumulated depreciation:

 

 

Results of operations

The following breakdown of results of operations summarizes income and expenses directly related to crude oil and natural gas production for the years ended December 31, 2025, 2024 and 2023. Income tax for these periods was calculated using statutory tax rates.

 

Estimated crude oil and natural gas reserves

Proved reserves as of December 31, 2025 and 2024, are net reserves attributable to Vista certificated by DeGolyer and MacNaughton for the assets located in Argentina, and Mexico.

Proved crude oil and natural gas reserves are the quantities of crude oil and natural gas 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 prior to the time at which contracts providing the right to operate expire, unless evidence indicates that renewal is reasonably certain, regardless of whether deterministic or probabilistic methods are used for the estimation. The project to extract the hydrocarbons must have commenced or the operator must be reasonably certain that it will commence the project within a reasonable time. In some cases, substantial investments may be required in related wells and facilities to recover proved reserves.

 

The Company considers that its remaining estimated volumes of crude oil and natural gas proved recoverable reserves are fair and that these estimates were prepared according to SEC regulations and ASC 932, as amended. Consequently, crude oil prices used in determining proved reserves were the average price during the 12 months prior to the end date of December 31, 2025, and 2024, respectively, determined as an unweighted average of the first day of the month for each month within these periods. Moreover, since there are no natural gas prices available in the benchmark market in Argentina, VISTA used the average natural gas prices for the year to determine natural gas reserves. In addition, for certain natural gas volumes, Vista will obtain an incentive price subsidized by the Argentine government through “Gas Plan IV”. A weighted average price is estimated for certain areas per subsidized and unsubsidized volume. The independent certificators carried out by DeGolyer and MacNaughton as of December 31, 2025 and 2024 in Argentina and Mexico, covered all the estimated reserves located in the areas operated and not operated by the Company.

4-10

S-X

The volumes of liquid hydrocarbons represent crude oil, condensate, gasoline and LPG to be recovered in field separation and plant processing and are reported in million barrels (“MMBbl”) The volumes of Natural gas represent expected gas sales and the use of fuel in the field and are reported in billion cubic feet (“Bcf”) (10) in standard conditions of 14.7 psia and 60°F. Gas volumes arise from the separation and processing in the field, which are reduced by injection, venting and shrinkage, and include the volume of natural gas consumed in the field for production. Natural gas reserves were converted into liquid equivalent using the conversion factor of 5.615 cubic feet of Natural gas per 1 barrel of liquid equivalent.

The following tables show proved oil reserves, net (including crude oil, condensate oil and LPG) and natural gas reserves, net, as of December 31, 2025, 2024, 2023 and 2022 according to VISTA’s interest percentage in the related concessions:

Proved reserves as of December 31, 2025

 

 

 

Proved reserves as of December 31, 2024

 

Proved reserves as of December 31, 2023

 

Proved reserves as of December 31, 2022

 

 

 

 

The following table shows the reconciliation of the Company’s reserve data between December 31, 2024, and December 31, 2025:

 

 

-13.72

(-0.14

-5.23

(-0.63

-3.09

BPE-conventional

(-0.02

-0.70

(-0.20

-0.29

 

(a) in connection with the proved developed reserves: (i) the acquisition of Trafigura’s working interest in Bajada del Palo Oeste resulted in additions of (+5.27 MMbbl and +4.63 Bcf); (ii) the acquisition of LACh’s working interest resulted in additions of (+61.6 MMbbl and +29.71 Bcf) (Note 1.2).

(b) in connection with the undeveloped reserves: (i) the acquisition of LACh’s working interest resulted in additions of (+65.0 MMbbl and +40.58 Bcf) (Note 1.2.2).

 

(a) in connection with the proved developed reserves: the increase is related to the successful drilling activities in the Vaca Muerta formation in: (i) LACh resulting in the addition of 45 gross wells (10 pads) (+26.10 MMbbl and +19.15 Bcf); (ii) BPE resulting in the addition of 9 wells (2 pads) (+10.10 MMbbl and +1.76 Bcf); and (iii) Bajada del Palo Oeste resulting in the addition of 17 wells (4 pads) (+11.69 MMbbl and +7.17 Bcf).

(b) in connection with the Proved undeveloped reserves enabled by drilling operations in the Vaca Muerta formation: (i) Aguada Federal resulting in the addition (+4.97 MMbbl y +2.16 Bcf); Bajada del Palo Este resulting in the addition (+19.30 MMbbl y +8.47 Bcf); and Bajada del Palo Oeste resulting in the addition (+41.62 MMbbl y +30.24 Bcf).

 

 

 

 

 

 

The following table shows the reconciliation of the Company’s reserve data between December 31, 2023, and December 31, 2024:

 

(-0.21

(-

(-

(-

(-

-

(-

3.02

1.63

0.59

(-

(-

(-

(-3.59

(-

(-

0.73

2.07

1.91

3.42

2.57

(-

(-

 

(a) in connection with the developed reserve: the increase are related: (i) the drilling success in Vaca Muerta formation of Aguada Federal with a 1 pad (3 wells) incorporating (+ MMbbl y + Bcf); (ii) Bajada del Este with a 2 pad (8 wells) (+ MMbbl y + Bcf); (iii) a 4 pad (13 wells) in Bajada del Palo Oeste incorporating (+ MMbbl y + Bcf).

Also, there is a neutral effect from the conversion of proved undeveloped reserves to proved developed reserves generated by: (i) the drilling success in Vaca Muerta formation of 5 pads (21 wells) in Bajada del Palo Oeste adding (+ MMbbl y + Bcf); (ii) the addition of 2 pads (5 wells) in Bajada del Palo Este incorporating (+ MMbbl y + Bcf); as well as (iii) the recategorizations in Bajada del Palo Oeste (Farmout Agreement I and II) adding (+ MMbbl y + Bcf ).

(b) in connection with the undeveloped reserve enable by the activity of drilling in Vaca Muerta formation of: (i) Aguada Federal adding (+ MMbbl y + Bcf), Bajada del Palo Este totaling (+ MMbbl y +Bcf), and Bajada del Palo Oeste, totaling (+ MMbbl y + Bcf).

 

 

 

 

V-1051

V-1052

V-1001,

V-1002,

V-1004

V-1006;

(-0.39

(-0.22

-2.05

 

(a) in connection with the developed reserve: (i) results of well tests for Aguada Federal MMbbl); (ii) Bajada del Palo Este 0.71 MMbbl); (iii) Bajada del Palo Oeste MMbbl); (iv) Bajada del Palo Oeste (Farmout Agreement II) MMbbl) especially in wells targeting the organic horizon; (v) CAN MMbbl) and the negative revision due to the retroactive adjustment of LPG plant in Entre Lomas Río Negro MMbbl); (vi) positive results in Bajada del Palo Este (+0.38 MMbbl); Bajada del Palo Oeste (+0.33 MMbbl); Bajada del Palo Oeste (Farmout Agreement II) (+0.77 MMbbl); (vii) combined effect of other fields MMbbl); and (viii) due to price changes MMbbl) effect.

(b) in connection with the undeveloped reserve: (i) they are related to an adjustment in Aguada Federal due to the latest well results MMbbl); (ii) the potential combined effect of other fields and rounding (+0.73 MMbbl), which includes the revision of reserves associated with the extension of the economic life of proved developed reserves in unconventional Bajada del Palo Oeste (Farmout Agreement I and II).

The changes from prior-estimate revisions of proved developed and undeveloped Natural gas reserves Bcf) are mainly related to:

(a) in connection with the developed reserve: (i) they are associated with the lower performance and adjustment of the GOR in the wells of Aguada Federal 4.3 Bcf), Bajada del Palo Este Bcf), Bajada del Palo Oeste Bcf), Bajada del Palo Oeste NOC Bcf), Bajada del Palo Oeste (Farmout Agreement I) Bcf), and Bajada del Palo Oeste (Farmout Agreement II) Bcf); (ii) for price changes, the variation was Bcf); and (iii) the rest due to the effect of other fields Bcf).

(b) in connection with the undeveloped reserve: (i) they are related to an update in Aguada Federal due to the latest well results Bcf); (ii) the potential combined effect of other fields and rounding (+0.70 Bcf), which includes the revision of reserves associated with the extension of the economic life of proved developed reserves in conventional Bajada del Palo Oeste, Bajada del Oeste, Bajada del Oeste (Farmout Agreement I), and Bajada del Oeste (Farmout Agreement II).

(a) in connection with the developed reserve: (i) due to the extension of (+0.2 MMbbl) from the successful drilling of two new Vernet-1051 and 1052 blocks; and (ii) the rounding effect MMbbl).

(a) in connection with the developed reserve: (i) The lower performance and price decrease Bcf); and (ii) due to the extension of (+3.3 Bcf) from the successful drilling of two new Vernet-1051 and 1052 blocks.

Standardized measure of future discounted cash flow (net)

This standardized measure is not intended to be, and should not be, interpreted as an estimate of the market value of the Company’s reserves. The purpose of this information is to provide standardized data to help the users of the financial statements to compare different companies and make certain projections. This information does not include, among others, the effect of future changes in price costs and tax rates, which past experience shows that they are likely to occur, and the effect of the future cash flows of reserves that have not been classified as proved reserves yet, of a discount factor that best represents the value of money over time and of the risks inherent in crude oil and natural gas production. These future changes may have a major impact on future net cash flows disclosed below. Therefore, this information does not necessarily show the Company’s perception on future discounted cash flow, net, of the hydrocarbon reserve.

 

 

 

 

Changes in the standardized measure of future discounted cash flow (net)

The following table shows the changes in the standardized measure of future discounted cash flow, net, for the years ended December 31, 2025, 2024 and 2023: