John Grace believes the stock market won't keep returning the kinds of yearly gains investors have gotten used to. "Our expectations around U.S. equity markets is for about a 5 percent median, annualized return," says the fund group's CIO. The stock market won't keep returning the kinds of yearly gains investors have gotten used to since the financial crisis bottom in 2009, Vanguard's chief investment officer, Greg Davis, said. "If we look forward for the next 10 years, our expectations around U.S. equity markets is for about a 5 percent median annualized return," he told CNBC. This means investor expectations will have to come more in line with reality.