***** EXTERNAL email. Please be cautious and evaluate before you click on links, open attachments, or provide credentials. ***** NOTICE DATE: June 1, 2018 NOTICE TYPE: W-B060118-01 Operations SHORT DESCRIPTION: Issue with the implementation of ITCM-104810 to improve the accuracy of indicative Locational Marginal Prices (LMPs) INTENDED AUDIENCE: ERCOT Market Participants DAY AFFECTED: May 31 through June 1, 2018 LONG DESCRIPTION: On May 31, 2018 12:00 am, ERCOT as part of Release 3 made two updates to the methodology for calculating indicative LMPs in Real-Time. One of the updates, specifically the new methodology for determining the Generation-to-be-Dispatched (GTBD) that is input for future intervals in the indicative pricing executions, was found to have an issue. This results in an underestimation of the magnitude of system-wide Load changes in future GTBD values. ERCOT has developed a fix for the issue and will be migrating it into production systems and available starting from 15:40 Indicative pricing run execution. Values posted prior to this fix will not be republished. 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 [log in to unmask]<mailto:[log in to unmask]>. If you are receiving email from a public ERCOT distribution list that you no longer wish to receive, please follow this link in order to unsubscribe from this list: http://lists.ercot.com. mm