Red alert: A $1 trillion stock bubble ready to pop By: CNBC.com News January 14, 2016 at 09:48 AM EST Hypergrowth in ETF Index funds is posing a big market risk, experts warn. It's time for investors to look at diversifying their holdings. Read More >> Related Stocks: Berkshire Bancorp Exxon Mobil General Electric JPMorgan Chase & Co Johnson & Johnson Microsoft PepsiCo Pfizer Procter & Gamble Wells Fargo