The 2010s have been somewhat unusual in that a simple passive investment in the S&P 500 index delivered higher risk-adjusted returns than almost any other asset class. Traditionally, the risk of stock drawdowns from all-time high levels has been mitigated by rebalancing some of the stock gains into bonds, with one rule of thumb being to maintain a portfolio of 60% stocks and 40% bonds. Rather than simply hoping that US stocks and bonds will continue their impressive past returns, this article aims to take a critical look at expected returns over the next 10