NOTICE DATE: December 15, 2025

NOTICE TYPE: M-A121225-02 Settlements

SHORT DESCRIPTION: Software Issue Identified Impacting Ancillary Service Trades

INTENDED AUDIENCE: All Market Participants

DAYS AFFECTED: December 8, 2025

LONG DESCRIPTION:  This is an update to the Market Notice issued on December 12, 2025, regarding the software issue identified preventing Ancillary Service Trades from being applied to a database table for downstream applications. See Market Notice M-A121225-01.

ERCOT was able to gather the missing Ancillary Service Trade records and rerun the optimization process to correct the Reliability Unit Commitment (RUC) Capacity Short data for Operating Day December 8, 2025 on the Initial Settlement Statements.

CONTACT: If you have any questions, please contact your ERCOT Account Manager. You may also call the general ERCOT Client Services phone number at (512) 248-3900 or contact ERCOT Client Services via email at ClientServices@ercot.com.

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dg