Check out the companies making headlines before the bell. Robinhood , AppLovin — The stock trading app and advertising technology company both surged 8% after S & P Global said the two will join the S & P 500 index , effective before trading opens Sept. 22. Passive index funds must buy shares of companies added to benchmark indexes in order to mirror their performance. Robinhood will replace Caesars Entertainment , while AppLovin replaces MarketAxess Holdings . Nutanix , TransUnion — Cloud software stock Nutanix climbed 3% after S & P Global added it to the S & P MidCapp 400 index, replacing Acadia Healthcare in the S & P MidCap 400. Consumer credit reporting agency TransUnion gained 2% after being added to the Midcap 400 to replace ManpowerGroup . Summit Therapeutics — The biopharmaceutical company plunged 21% after results from a Phase 3 trial showed Summit’s lung cancer drug, ivonescimab, resulted in fewer improvements in European and North American patients compared to their Chinese counterparts. Gold miners — Gold miners rose after the Financial Times reported that Tether, the world’s largest stablecoin company, held talks to invest in gold mining. The FT said Tether is eyeing investing in the entire gold supply chain, citing four people familiar with recent talks. Harmony Gold Mining added 5%, Hecla Mining and Gold Fields climbed 4%, Anglogold Ashanti rose 3% and Coeur Mining advanced 2%. Tesla — The electric vehicle maker edged up 1% in the wake of CEO El …
