Company: VIST
Filing Date: 2025-04-16
Form Type: 6-K
Source: 0001193125-25-082223
Chunk: 66

Company: Vista Energy, S.A.B. de C.V.
Filing Date: 2025-04-16
Form: 6-K
Chunk 66
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 and for obtaining sufficient and adequate evidence as to whether:

| • |     | The related proforma adjustments give appropriate effect to those criteria; and |

| • |     | Pro forma financial information reflects the proper application of those adjustments to unadjusted financial 
 information.                                                                                                 |

The proceedings were conducted based on our judgment, taking into account the independent public accountant’s understanding of the nature of Vista Energy, S.A.B. de C.V., the event or transaction, with respect to which the pro forma financial information has been collected, and other circumstances relevant to our work. Our work also involves evaluating the overall presentation of the consolidated pro forma financial information as a whole. We consider that the evidence we have obtained is sufficient and adequate to provide a basis for our opinion. 3

Opinion In our opinion, Vista Energy, S.A.B. de C.V.’s proforma financial information has been reasonably compiled in all material respects, in accordance with the requirements of the Circular Única de Emisoras and is consistent with the Company’s accounting policies and based on the assumptions included in the proforma financial statements. Other Matters The unaudited pro forma consolidated financial information included in the pro forma financial statements was prepared based on the information available to the acquiree and on assumptions that Vista Energy, S.A.B. de C.V., management believed to be reasonable as of the date of the acquisition.

| Mancera, S.C.                              |
| Integrante de Ernst & Young Global Limited |
| /s/ Arturo Figueroa Carmona                |
| C.P.C. Arturo Figueroa Carmona             |
| Mexico City, Mexico                        |
| April 15, 2025                             |

4

VISTA ENERGY, S.A.B. DE C.V. Unaudited pro forma consolidated statement of profit or loss and other comprehensive income for the year ended December 31, 2024 (Amounts expressed in thousands of US Dollars)

|                                                                                          |     |     | Notes |     |     |   Year ended 
 December 31, 
         2024 |   |     |     |   Pro forma 
 adjustments 
        2024 |   |     |     |   Year ended 
 December 31, 
         2024 
    Pro forma |   |
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