It may seem like a fairly safe bet. Withdraw no more than 4 percent from your retirement savings each year, and you'll have enough to last the rest of your life.
After all, many people's biggest fear in facing retirement is the possibility of outliving their money. To make sure retirees have enough money, many financial advisors have relied on a rule that a nest egg should hold out as long as they withdraw a maximum of 4 percent annually.
But some certified financial planners now say the so-called 4 percent rule could put your retirement savings at risk.
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"I don't think the 4 percent rule is as feasible today as it was in the past, and the reason for that is because the market returns haven't been as consistent as we've seen in the past," said Richard Coppa, managing director of Wealth Health.
The rule, calculated in the 1990s, was based on a model portfolio that contained a certain mix of stocks and bonds: 60 percent large-cap stocks and 40 percent intermediate-term government bonds.
Times have changed, though. And with historically low bond yields and a volatile stock market, the rule may no longer apply.
"In the last decade, we've seen a dot-com bubble, we've seen a real estate bubble, we've seen a financial crisis—and all of that impacts the types of returns we're getting on both stocks and bonds," Coppa said.
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To make sure clients don't outlive their savings, Coppa advises them to get a handle on their cash flow. Managing income and expenses in retirement is more important than relying on any rule, he said. Bottom line, knowing what you'll spend is the best way to determine what you'll be able to withdraw.
But Doug Lockwood, a certified financial planner with Harbor Lights Financial, said it is possible for retirees to withdraw 4 percent a year from savings and have the money last—as long as the mix of assets is well-diversified. A model portfolio of 60 percent stocks and 40 percent bonds could work, depending on the type of equities.