When it comes to saving for college, many families are attracted to the way they can put their investments on autopilot in an age-based 529 portfolio.

These popular college savings portfolios shift assets from riskier types of asset s, such as stocks, to more stable investments, such as bonds and T reasury notes, as the recipient nears college.

The idea is that investors plug in the age of the child or an expected high school graduation date, then “set it and forget it” — trusting that the portfolio will do its job of accruing money in the early years and maintaining a reliable balance when the money is needed for college.

“As you start approaching those years (near graduation), parents want to know how much money they have,” says Duy Nguyen, chief investment officer of Invesco Solutions, the investment manager for Rhode Island’s 529 plan. “They want to have a stable number that they can count on. They also want to know as college inflation increases, that this portfolio will perform commensurate with those increases.”

However, not all age-based portfolios are created equal, and the way they are structured can differ dramatically from plan to plan. Families should ask the following three questions when choosing an age-based plan .

[Discover the pros and cons of college savings plans.]

— Does it match my risk profile? Some 529 plans invest very conservatively when the student is near or in college, while others maintain a significant investment in stocks and longer-term bonds, according to a recently-updated study conducted by savingforcollege.com, a website that compares college savings plans.

“During the college years you have many plans that have 100 percent fixed income,” says Brian Boswell, the site’s vice president for research and development . “Then you’ll go to another plan and it’ll have 10 or 20 percent equity in it, the theory being that you need that additional return to afford the last few years of college.”

And while some plans offer a conservative, moderate and aggressive option, not all do. Some only offer a “one-size-fits-all” option, which may not match your risk tolerance, Boswell says.

If that’s the case, you have a few options, Boswell says. For one, families can choose a plan in another state. There’s no requirement to use your own state’s plan, although many states offer a tax perk for choosing an in-state portfolio.

Families may also want to consider opening more than one account. By mixing and matching, you could reap the rewards of your state’s tax benefit and another state’s preferred portfolio. Or you could put some savings into an age-based portfolio and some into a static portfolio.

Another strategy is to choose a different target graduation date. For instance, if you want a portfolio with less risk, choose an earlier graduation date, which will shift your assets into a more conservative portfolio more quickly.

[Explore ways to vary college savings strategies.]

— Do I like the underlying investments? Most 529 plan managers will take a broad asset allocation approach to age-based portfolios, but it’s still smart to know what asset classes are used in your plan.

“You do want to look at what you’re investing in,” Boswell says. “Some might have real estate or international stocks, or small-cap stocks. Others might have only domestic options. Just know every plan is a little different and it is important to understand what you are putting your money into.”

Investors can dig into the underlying investment by checking their plan’s website, or if the information isn’t readily available, by contacting the plan. It’s common for a small percentage to go toward more “exotic” assets, such as emerging markets, international stocks, small-cap stocks — those of companies with relatively small market capitalization — or real estate, but most plans won’t put huge stakes in them, Boswell says.

If an investor is turned off by a particular asset class, he or she could shop around for a plan that avoids it, he says, or build his or her own portfolio.

[Know when to shift age-based college savings.]

— Do I like the pace that the assets shift? Age-based portfolios for college savings are often compared with target-date retirement portfolios, with some key differences: College savers have much less time to save and a much shorter period of time when they will need the money.

Because of this shorter timeline, some portfolios abruptly shift asset allocation in a single day — sometimes by double-digit percentage points — as they shed stock holdings in favor of more stable asset classes. These single – day shifts can “court significant market risk,” according to a 529 report by the financial research firm Morningstar.

“Investors may want to think twice about the potential impact — psychological or otherwise — of a large portion of assets being sold at market lows due to an age-based portfolio’s large allocation step-down,” according to the Morningstar report.

Other portfolios use a more “progressive” age-based portfolio, divesting stock by a few percentage points per year, according to Morningstar. More plans are starting to use this smoother rebalancing process, according to Morningstar, although some argue it’s more expensive and the costs outweigh the benefits.

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3 Questions to Ask About Age-Based 529 Plan Investments originally appeared on usnews.com