Stitch Fix rises on better than expected 3rd-quarter results. Chico’s gets involved in an activist investor battle. Berkshire-Hathaway invests $500 million in Nubank, an online bank in Brazil. Jim Gillies analyzes those stories and shares why he believes we’re living in a golden age of “The Greater Fool” theory.   Want 50% off our Stock Advisor service? Just go to http://StockIdeas.fool.com.