Vistra is trading 10.72% lower at $120.84, with no company-specific announcement identified; broader energy-sector weakness may be contributing. - Oil-price declines and election-related uncertainty are weighing on energy-market sentiment, but do not establish the cause of the unusually sharp drop; major U.S. indices are higher. - Vistra is scheduled to report third-quarter results on November 6; recent analyst price-target cuts were reported in late October.