Vistra Corp.

8. LOSS EVENTS AND INSURANCE RECOVERIES

Moss Landing 300 Incident

On January 16, 2025, we detected a fire at our Moss Landing 300 MW energy storage facility at the Moss Landing Power Plant site (the Moss Landing Incident) that resulted in ceasing operations at all facilities at the Moss Landing complex until the fire was contained. No injuries occurred due to the fire or the Company's response. The Moss Landing complex includestwo other battery facilities and a gas plant. The gas plant returned to service in February 2025. The Moss Landing 350 MW battery facility has a net book value of approximately $320 million as of December 31, 2025. We are working towards a return to service in mid-2026, but we will continue to evaluate our restart plans following completion of our investigation into the cause of the fire. After further consideration, management determined it would not return the Moss Landing 100 MW battery to service.

As a result of the damage caused by the Moss Landing Incident, during the three months ended March 31, 2025, we wrote-off the net book value of Moss Landing 300 of approximately $400 million to depreciation expense and moved the asset to the Asset Closure segment as we have no plans to return the Moss Landing 300 facility to operations (see Notes 7 and 21 for additional information).

As a result of the decision to not return the Moss Landing 100 MW battery to service, we performed an assessment of the recoverability of the facility's carrying value and, during the three months ended December 31, 2025, we recognized an impairment loss of approximately $155 million and moved the asset to the Asset Closure segment (see Notes 7 and 21 for additional information).

In July 2025, we entered into an Administrative Settlement Agreement and Order on Consent (ASAOC) with the EPA related to the Moss Landing 300 site. Under the ASAOC, we are required to perform specific battery removal and remediation activities, including battery removal and disposal, building demolition, and air and water monitoring. We estimate the total cost of these activities to be approximately $110 million. We have incurred expenses of approximately $49 million on ASAOC activities through December 31, 2025. As of December 31, 2025, our accrual for estimated future costs for the ASAOC activities is approximately $61 million, which is reflected inother current liabilities in the consolidated balance sheets. This estimate assumes the ASAOC activities will be completed by the end of 2026. Aside from battery removal and disposal, our estimate does not reflect costs associated with removal of other hazardous waste that could be identified as the demolition progresses as we are unable to estimate such costs until sampling of waste material is complete. We will account for any adjustments to the accrual as a change in estimate in the period new information becomes available.

Additional impacts from the Moss Landing Incident include loss of revenue from the facilities being offline and may include litigation costs, other negotiated settlements of contracts with counterparties, and additional non-cash impairment losses. See Note 18 for additional information.

We have filed insurance claims against applicable insurance policies with combined business interruption and property loss limits of $500 million, net of deductibles, of which approximately $500 million has been collected through February 2026. The initial insurance receivable asset related to expenses we believe were probable of recovery from property damage insurance was $425 million, recorded as offsets to the expenses incurred in other noncurrent assets in the consolidated balance sheets. See Insurance Recoveries for additional information. While we expect future revenues in the West segment to decrease relative to 2024 revenues with the Moss Landing 300 and 100 MW battery facilities not returning to service, given the uncertainty in the timing of the restart of the Moss Landing 350 MW battery facility and additional expenses that could be incurred related to the Moss Landing Incident, we cannot predict the full impact this event will have on our 2026 financial statements.

Martin Lake Unit 1 Incident

On November 27, 2024, we experienced a fire at Unit 1 of our Martin Lake facility in ERCOT (the Martin Lake Incident), an 815 MW unit. We wrote-off the unit's net book value of less than $1 million to depreciation expense in December 2024. The unit returned to service in February 2026. We estimate total cash capital expenditures required to restore the unit to service was approximately $384 million, of which approximately $271 million in cash capital expenditures have been incurred as of December 31, 2025.

We expect to recover a majority of the expenditures associated with the Martin Lake Incident through property damage insurance and to receive additional business interruption proceeds. During the year ended December 31, 2025, we recognized property damage insurance recoveries of $160 million, of which $40 million was recorded as an offset to operating costs incurred to restore the unit to service, and $120 million was recorded as a gain in other income, net in the consolidated statements of operations. During the year ended December 31, 2025, we recognized business interruption insurance proceeds of $47 million recorded in operating revenues. See Insurance Recoveries for additional information.

Insurance Recoveries

The following table summarizes the expenses recorded, net of property damage insurance recoveries, related to the Moss Landing Incident and Martin Lake Incident during the year ended December 31, 2025.

(a)Total estimated costs of ASAOC activities is expected to be approximately $110 million, of which $102 million was recorded in operating costs in the consolidated statements of operations. Amounts above exclude $8 million of estimated demolition and battery removal costs reclassified from the Moss Landing 300 ARO to other current liabilities during the three months ended March 31, 2025.

(b)Property damage insurance receivable is included in other noncurrent assets on the consolidated balance sheets.

The following table summarizes the business interruption insurance recoveries related to the Moss Landing Incident and Martin Lake Incident during the year ended December 31, 2025.

(a)Business interruption insurance proceeds are included in operating revenues in the consolidated statements of operations.

We expect to receive additional property damage and business interruption insurance proceeds related to the Martin Lake Incident and additional business interruption insurance proceeds related to the Moss Landing Incident which are not included in the property damage insurance receivable as of the year ended December 31, 2025. These additional proceeds will be recorded as income in the period they are realized.