If you're already retired or approaching retirement and your portfolio is overweight U.S. stocks, these forecasts should cause some concern. According to Vanguard, the U.S. stock market is expected to deliver an annualized return of between 3.3% to 5.3% over the next 10 years. But it's the forecast about stocks that should raise alarm bells for many U.S. retirees. It's a real heavyweight in the American stock market (1). It's worth taking any future prediction of the stock market, even the ones from trillion-dollar fund managers, with a grain of salt.