Vistra Corp.

15. ASSET RETIREMENT OBLIGATIONS

Our AROs primarily relate to nuclear generation plant decommissioning, land reclamation related to lignite mining, remediation or closure of coal ash basins, and generation plant disposal costs. AROs are based on legal obligations associated with enacted law, regulatory, or contractual retirement requirements for which decommissioning timing and cost estimates are reasonably estimable.

The following table summarizes the changes to our current and noncurrent ARO liabilities for the nine months ended September 30, 2026 and 2025:

(a)For the nine months ended September 30, 2026 and 2025, nuclear plant decommissioning accretion includes $75 million and $70 million, respectively, of accretion expense recognized in operating costs in the condensed consolidated statements of operations and $48 million and $44 million, respectively, reflected as a change in regulatory liability in the condensed consolidated balance sheets.

(b)There is a corresponding non-cash change in property, plant, and equipment related to land, reclamation, coal ash, and other ARO adjustments of $(7) million and $(14) million for the nine months ended September 30, 2026 and 2025, respectively.

Nuclear Decommissioning AROs

AROs for nuclear generation decommissioning relate to the Comanche Peak plant in ERCOT and the PJM nuclear facilities. To estimate our nuclear decommissioning obligations we use a discounted cash flow model which, on a unit-by-unit basis, considers multiple decommissioning methods and is based on decommissioning cost studies, cost escalation rates, probabilistic cash flow models, and discount rates.

As of September 30, 2026 and December 31, 2025, the carrying value of our ARO related to our Comanche Peak nuclear generation facility decommissioning totaled $1.885 billion and $1.838 billion, respectively, which is lower than the fair value of the assets contained in the Comanche Peak NDT of $2.688 billion and $2.589 billion, respectively. As of September 30, 2026 and December 31, 2025, the difference between the carrying value of the ARO and the NDT represents a regulatory liability of $803 million and $751 million, respectively, recorded to the condensed consolidated balance sheets in other noncurrent liabilities and deferred credits since any excess funds in the NDT after decommissioning our Comanche Peak plant would be refunded to Oncor.

The carrying value of our ARO for our PJM nuclear facilities was recorded at fair value on the date of the closing of our merger with Energy Harbor in March 2024. ARO accretion expense attributable to the PJM nuclear facilities is reflected in operating costs in the condensed consolidated statements of operations. ARO estimates for the PJM nuclear facilities will be evaluated on an individual unit basis at least every five years unless triggering events warrant a more frequent review. Any changes in ARO estimates are recorded as an increase or decrease in ARO liability along with a corresponding change to asset retirement cost asset within property, plant, and equipment in the condensed consolidated balance sheets; however, if the ARO estimate decreases by more than the remaining ARO asset, the balance of the change is recorded as a reduction to operating costs in the condensed consolidated statement of operations.