NOTICE DATE: March 18, 2026

NOTICE TYPE: R-A031826-01 Testing

SHORT DESCRIPTION: Retail Market Qualification Testing (Flight 0626) begins May 12, 2026, application processing deadline of April 15, 2026, and a registration deadline of May 6, 2026.

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

DAYS AFFECTED: April 15, 2026 - June 22, 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 0626. Flight 0626 tests for TX SET Version 5.0 and is scheduled to begin May 12, 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 (new DUNS+4) 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 0626.

Deadlines are:

• The Application Processing Deadline for New CRs and DUNS+4 entities to enter Flight 0626 is April 15, 2026 at 17:00 CPT.
• The Registration Deadline for participating in Flight 0626 - Retail Market Testing is May 6, 2026 at 17:00 CPT.

New CRs participating in Flight 0625 are requested to have their banking information established prior to the Flight deadline, May 6, 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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dsl