S&P 500: AI Play Vistra Joins Index; Bitcoin Miner Marathon Digital Rallies On Demotion

Vistra (VST) is set to join the S&P 500, replacing Pioneer Natural Resources, while its stock surged by 4.2% after the announcement, benefiting from increased demand in the AI sector. Meanwhile, Marathon Digital (MARA) will move to the S&P SmallCap 600, experiencing a stock rise of 4.85%, viewed positively due to broader fund tracking. Conversely, AAON will ascend to the S&P MidCap 400 but faces potential reductions in mandatory fund holdings, leading to a 3% drop in its stock.