Rebalancing the assets in your portfolio back to a target weight is an often-cited common sense tenet of investing. But legendary Vanguard Founder Jack Bogle says you might want to think twice about doing so.

Boggle tells Money magazine that “If you can ignore market fluctuations along the way, it’s better not to rebalance, since you’re likely to get higher returns.” In a recent study, he looked at how a portfolio with 70% in stocks and 30% in bonds performed when rebalanced annually vs. when left alone. “Over the 187 25-year periods ending between 1826 and 2012, the rebalanced portfolio earned a sliver less on average,” Money reports.  “In 55% of the periods, rebalancing beat doing nothing, by an annualized 0.23%, adjusted for inflation. When rebalancing hurt returns, the penalty was larger — 0.43%.”

The problem, however, is that most investors don’t have the stomach to sit tight. So Bogle does support a modest rebalancing plan. “For behavioral reasons,” he says, “most investors are happier if they rebalance, and that’s worth something too.”