Those who stick to the convention of annually spending no more than 4% of their initial retirement savings—adjusted each year for inflation—can "use the tax code to make their portfolios last up to seven years longer," says Baylor University Prof. William Reichenstein, a principal at Retiree Inc., a Leawood, Kan., company that helps retirees plan tax-efficient withdrawals.
How It Works
For simultaneous withdrawals to work, retirees should have at least two of the following three types of accounts: regular tax-deferred IRAs and 401(k)s; tax-free Roth IRAs and 401(k)s; and regular taxable accounts.
The first step, he says, is to put off claiming Social Security. A delay will increase their future benefit and reduce the amount of those benefits subject to tax.
In the interim, Mr. Barber says, the couple should withdraw the $70,000 from the taxable account. At that rate, the $300,000 account will support them for about four years.
To see why, consider what will happen in four years, when the couple drains the $300,000 taxable account. At 66, they will qualify for a combined $44,000 in Social Security—or 33% more than they would have received at 62, says Mr. Barber.
From a tax perspective, a bigger Social Security benefit is good news. Why? The formula that determines how much of an individual's Social Security is taxable counts only half of a person's Social Security income. So, in contrast with income from a regular IRA, "you can receive twice as much Social Security income before you ever trigger a tax" on your benefits, says Mr. Mahaney of Prudential.
The couple is also likely to reap future tax benefits. Thanks to the Roth conversions, their tax-deferred IRAs will be smaller. Thus, when required distributions from those IRAs begin at 70½, the withdrawals—and the taxable income they create—will be lower. And tax-free Roth withdrawals can supplement income in years in which tapping other accounts would push them into a higher tax bracket.
The math is sticky, but the benefits can be large.