This surprising investment strategy could boost your retirement nest egg—but proceed with caution

Increasing your stock exposure as you go through retirement can be risky, but it can also be fruitful.
Increasing your stock exposure as you go through retirement can be risky, but it can also be fruitful. - Getty Images

With the S&P 500 SPX up about 20% on the year and bonds lagging, it can be tempting to forget about safety and try to catch the upward wave.

If you’re trying to decide on the best portfolio ratio for right now — whether you’re 25, 40 or even 60 — this isn’t the most consequential decision you can make with your investments, because you still have a long time ahead to make adjustments. But if you’re already retired, it’s one of the most important things you have to decide, and even more so if you’re newly retired. The liftoff of your retirement path is extremely important, and then you have to keep track of where you go from there.

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This glide path, as the experts call it, traditionally gets more conservative as you age. This is how most target-date funds work in workplace retirement accounts, and how most professional advisers arrange portfolios for clients. You might start with a high ratio of stock versus bond investments — maybe as high as 80% — and over time get that down to 30% or less by the time you’re in your late 70s or 80s.

There’s also a theory that reverses that: One where you start out more cautious in the early years of retirement when your returns matter most, and then get more aggressive as you age. The theory is that as your nest egg gets smaller, you have to work it harder. It’s an all-in scenario, one that is still attracting adherents as market conditions swing toward high equity returns and still-low interest rates on fixed income.  It also works for wealthier retirees who are investing funds they intend to pass on to heirs or charity.

“I still think the idea holds up,” said Wade Pfau, one of the retirement experts, along with Michael Kitces, who have published research on what they called “rising equity glide paths.

Why not go all in?

Retirement expert David Blanchett tested more than 6,000 scenarios to see which glide path was best nearly 10 years ago for a research paper. The differences among the different options weren’t staggering, but significant enough to declare a clear winner: the traditional declining equity glide path.