For Retirement Portfolios, a Smarter Glidepath

retirement-exit-2My Comments: I’ve talked in earlier blog posts about the rate used to withdraw money from your retirement accounts. There is a prevailing sentiment that it should be 4% or less. I think that’s too low. On the other hand if I’m wrong, and 30 years later you discover you have run out of money, it’s unlikely I’ll be here to take your blame.

Having said that, I think a 6% extraction rate is more realistic. Only how much more money that actually gives you is hard to imagine. That’s because it’s a function of how fast the money left in your accounts actually grows.

My experience, though thick and thin, meaning good years and bad years, is that you should be able to grow your money at 7 to 8% per year. I’m now using programs that when backtested over the past dozen years, which includes the crash of 2008-09, have grown at 10%.

The argument against that is that as we all know, past performance is no guarantee of future performance. But it is a clue, and with advances in technology and tactical approaches to investing, a higher number is far more realistic, in my opinion.

by Michael Kitces / AUG 25, 2014

One of the core functions of financial planning is setting up clients’ portfolios in retirement so that resources are adequate to sustain the journey — no small feat, given the uncertainties involved and the need to balance stability and safety against the risk of inflation, as well as the need for growth over the potentially long time horizon.

Conventional wisdom suggests that retirees should manage this challenge by having a moderate exposure to stocks at the start of retirement — to help their portfolio grow and be able to keep up with inflation over the long run — and then reduce equity exposure slowly over time as they age and their time horizon shrinks.

But recent research has suggested that the optimal approach might actually be the opposite — start with less equity exposure early in retirement, when the portfolio is largest and most vulnerable to a significant market decline, and then slightly increase the equity exposure each year throughout retirement.

And as it turns out, an even better approach may be to accelerate the pace of equity increases a bit further in the earlier years (from an initially conservative base). After all, a slight equity increase in the last year of retirement isn’t really likely to matter.

For instance, a glidepath might aim to increase equities in just the first half of retirement, until the target threshold is reached, and then level off. Instead of gliding to 60% equities from 30% over 30 years, glide up to 60% over 15 years — then maintain that 60% equity exposure for the rest of retirement (assuming the 60% target is consistent with client risk tolerance in the first place).

Accelerating the glidepath reduces the time when the portfolio is bond heavy — a particular concern in today’s low interest-rate environment. And it may be even more effective to simply take interest-rate risk off the table altogether by owning short-term bonds instead. Such an approach leads to less wealth on average, but in low-return environments, rising-equity glidepaths that use stocks and Treasury bills can actually be superior to traditional portfolios using stocks and longer-duration bonds (say, 10-year Treasuries) — even though Treasury bills provide lower yields.

FASTER GLIDEPATH

In the original research that American College professor Wade Pfau and I collaborated on, showing the benefits of a rising-equity glidepath, we simply assumed that any retiree using a glidepath would make adjustments in a straight line throughout retirement. For instance, gliding equities to 45% from 30% during a 30-year retirement time horizon would require a shift of 0.5% per year.

Gliding to 60% from 30% in the same time horizon would involve shifting 1% per year.
Yet the reality in such situations is that, for someone who is spending down assets, the last 1% change in equity exposure (to 60% from 59%) in the 30th year is not going to impact the outcome. At that point, the retiree has either made it or not.

So we launched a follow-up study, testing the impact of an accelerated glidepath. In this case, instead of moving to 60% equities from 30% over 30 years, the retiree moves there in only 15 years (at 2% per year), and then plateaus.

To test the alternatives, we looked at how they would have performed historically compared with each other with a 4% initial withdrawal rate over rolling 30-year periods in the U.S., starting each year since 1871, assuming a combination of large-cap U.S. stocks and 10-year Treasury bonds that are annually rebalanced.

The results, shown in the “How Fast a Glidepath?” chart below, reveal that the accelerated glidepath over 15 years is superior to the 30-year glidepath. In most years, the difference is fairly small — an improvement of the safe withdrawal rate of 0.1 to 0.2 percentage points — but in the best years, the improvement was as much as roughly half a percentage point.

The accelerated glidepath is ultimately better in all historical scenarios and improves outcomes in both high-return and low-return eras. It’s only a question of how much.

INTEREST-RATE RISK

A commonly voiced concern about our original rising-equity glidepath research was the fact that being more conservative with equities in the early years also means owning more in bonds. That’s not necessarily appealing in light of today’s low interest rates and the fear that rates will rise at some point in the coming years.

Accordingly, in our follow-up research we also tested the impact of taking interest-rate risk off the table, by using portfolios of stocks and Treasury bills, instead of stocks and 10-year Treasury bonds. The benefit of using Treasury bills is that, because they mature in a year or less, they are reinvested annually, avoiding any risk that the retiree will need to liquidate bonds at a loss because of rising rates. The downside, of course, is that shorter-term Treasury bills generally have lower yields over time (at least in any normal, upward-sloping yield curve environment).

As shown in the “Bills vs. Bonds” chart below, there are times when Treasury bills help, and times when they hurt. The difference in outcomes between using Treasury bills and bonds is as much as a half-percentage point improvement in safe withdrawal rate, and as bad as a 2-point decrease. ( No chart here. Please continue reading by clicking HERE )

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