Wall Street is starting to worry about a 'lost decade' for US stocks

Wall Street forecasters are starting to get nervous about the 10-year outlook for US stocks. Some see a "lost decade" in which the S&P 500 remains flat or lags behind the rest of the world. Returns could be held back due to high valuations and the market's record-breaking run in recent years. A dark thought is starting to circulate around Wall Street. What if, after years of stellar gains, the US stock market is basically flat for the next decade? That feels like an unbelievable idea given the cu ...