Bloom Energy Corp., Illumina Inc. and Everpure Inc. rallied in extended trading Friday after S&P Dow Jones Indices announced their addition to the S&P 500. Bloom Energy rose 7.5% after hours, while Illumina gained 2% and Everpure advanced 2.2%. The changes take effect before the opening bell on Monday, September 21, replacing Molson Coors Beverage Co., The Trade Desk Inc. and Builders FirstSource Inc.; Builders FirstSource fell 1.8% in post-market trading. Index-tracking funds are preparing to rebalance their portfolios, while Everpure and Illumina leave the S&P MidCap 400 and the three departing S&P 500 companies move to the S&P SmallCap 600. S&P Dow Jones Indices also announced broader changes, including adding Dell Technologies, Palo Alto Networks, Arista Networks and Sandisk to the S&P 100. HubSpot Inc. gained 4% after hours following its promotion to the S&P MidCap 400, alongside AGNC Investment Corp., Corcept Therapeutics and Brinker International.