NOTICE DATE: January 2, 2026

NOTICE TYPE: M-A121225-03 Operations

SHORT DESCRIPTION: Update: Software Issue Identified Impacting Ancillary Service Trades

INTENDED AUDIENCE: All Market Participants

DAYS AFFECTED: December 5, 2025 to December 10, 2025

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

ERCOT has reviewed the impact to the Real-Time Market (RTM) for Operating Days (OD) December 5, 2025 through OD December 10, 2025, and determined that it is not able to perform a price correction as accurate prices can not be determined, pursuant to Nodal Protocol Section 6.3(4). The RTM impacts for these ODs are specific to the validation of Ancillary Service self-provision resulting from the software issue, as further described in the previous Market Notice. 

ERCOT staff expects to share further details on this issue and be available for questions at the next Real-Time Co-optimization plus Batteries Task Force (RTCBTF) meeting, currently scheduled for January 20, 2026.

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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