NOTICE DATE: October 13, 2025

NOTICE TYPE: M-B101325-01 Operations

SHORT DESCRIPTION: Price Correction due to SCED Failure

INTENDED AUDIENCE: All Market Participants

DAYS AFFECTED: October 8, 2025

LONG DESCRIPTION: On Operating Day (OD) October 8, 2025, a software defect caused Security- Constrained Economic Dispatch (SCED) to fail to run for intervals 08:05 through 08:40. SCED subsequently ran successfully at 08:44. The root cause was determined to be a Market Management System (MMS) software defect that was triggered when a Resource's Three Part Offer) with NULL percentage values for Fuel Index Price (FIP) and Fuel Oil Price (FOP) was submitted after the Adjustment Period.

Upon completion of the impact analysis, ERCOT determined that the impact to prices met the significance criteria in ERCOT Protocols Section 6.3(5) to pursue a price correction for OD October 8, 2025. ERCOT corrected prices for OD October 8, 2025 before the deadline of October 10, 2025 at 4:00 PM.  Pursuant to ERCOT Protocols Section 6.5.9.2(2), in the process of correcting prices, prices were held for 15 minutes after the 08:44 SCED run.

Price correction files for OD October 8, 2025 have been posted on the Market Information System (MIS).

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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