NOTICE DATE: December 3, 2025

NOTICE TYPE: R-A120325-01 Testing

SHORT DESCRIPTION: Retail Market Qualification Testing (Flight 0226) begins February 3, 2026, application processing deadline of January 14, 2026, and a registration deadline of January 28, 2026

INTENDED AUDIENCE: Existing and potential new Competitive Retailers (CRs) and Transmission Distribution Service Providers (TDSPs)

DAYS AFFECTED: January 14, 2026 - March 6, 2026

LONG DESCRIPTION: ERCOT and the Texas Standard Electronic Transaction (TX SET) Working Group announce preparations are underway for the next round of Retail Market Qualification Testing, Flight 0226. Flight 0226 tests for TX SET Version 5.0 and is scheduled to begin February 3, 2026.

Registration for this Flight will be completed in the FlighTrak system.

Testing is required for:

• new Market Participants (CRs and TDSPs) entering the Texas Retail Market,
• existing Market Participants
• entering new service territories,
• testing additional business functionality,
• changing service providers,
• changing banking information, or
• adding another entity to their business umbrella.

Participation in Out of Flight Testing is limited to existing Market Participants (CRs and TDSPs) that did not make the deadline for the actual Flight Test and is subject to Flight Administrator and TDSP approval. Out of Flight testing includes testing for changing service providers to an existing service provider and changing banking information.

ACTION REQUIRED: Please see the "Approved 2026 Test Flight Schedule" on Texas Retail Market Testing page and the Retail Market Test Flight Information page of ERCOT.com for all registration and deadline information for Flight 0226.

Deadlines are:

• The Application Processing Deadline for New CRs and DUNS+4 entities to enter Flight 0226 is January 14, 2026 at 17:00 CPT.
• The Registration Deadline for participating in Flight 0226 - Retail Market Testing is January 28, 2026 at 17:00 CPT.

New CRs participating in Flight 0226 are requested to have their banking information established prior to the Flight deadline, January 28, 2026 at 17:00 CPT.

ADDITIONAL INFORMATION: Available documents for Texas SET Version 5.0 are on ERCOT.com.

"Retail Market Testing Orientation information" is found on the Texas Retail Market Testing page of ERCOT.com.

The Flight Testing information is found in the "Texas Market Test Plan 120119" on the Texas Standard Electronic Transaction Working Group page on ERCOT.com.

The "FlighTrak Users Guide" is found on the Texas Retail Market Testing page of ERCOT.com.

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