CNBC's Bob Pisani spoke with Burton Malkiel, professor emeritus of economics at Princeton University and author of “A Random Walk Down Wall Street,” and Dave Nadig, chief investment officer and director of research at ETF Trends. They discussed the evolution of retail trading, ESG, the market sell off and what investors should expect going into the end of the year. In the 'markets 102' portion of the podcast Bob will continue his exclusive interview with investing legend Burton Malkiel.