The Fashionable Investing Trend You Should Avoid

Value investing, the art of finding gems among beaten-down stocks, is a time-honored strategy. But recently a simple approach to value has become fashionable: Instead of hunting for bargains, buy all the stocks in the market, but "tilt" so that you own more of those with low prices relative to earnings or underlying business value. Academic research says it earns some extra return, and now lots of mutual funds and ETFs offer such statistical value plays.

So it might surprise you to learn that from 1991 to 2013, investors in value funds underper-formed the S&P 500 by close to a percentage point a year, according to an analysis of fund data by Research Affiliates.

Does this mean the value premium is overhyped?

No, it's just misunderstood. The same study showed that value funds beat the market by nearly half a percentage point annually over this stretch. But, on average, investors in those funds didn't capture that edge, because they traded at the wrong times, piling in when the style was hot and selling only after the funds had underperformed. So before you go after the so-called value effect, keep two things in mind.

Value Isn't a Short-Term Play

Although there's evidence that value works in the long run, "you can go decades where value is either in or out of favor," says Gregg Fisher, chief investment officer for Gerstein Fisher. Indeed, growth stocks—the high-priced antithesis to value shares—largely outpaced the broad market from 1988 to 2000.

"The worst thing you can do is try to time value," says Jason Hsu, vice chairman at Research Affiliates. If you wait to snap up such stocks until after they've done well, you lose part of their advantage—the low prices.

Tilt Lightly (Especially Now)

The investment community has lately gone on a tilting spree. Rick Ferri, founder of Portfolio Solutions, warns that there's "an awful lot of money going into a small group of securities." And there's evidence that the market has changed as a result: The stocks with the lowest price/earnings ratios are now only 15% cheaper than those with the highest P/Es. The value discount has been closer to 35% in the past.

Ferri recommends keeping the majority of your stock portfolio in an index fund or something else that's in line with the broad market, devoting no more than 25% to value or other kinds of tilts. And don't do it at all unless you expect to be invested for a long time. Says Ferri: "With all this recent attention, it might take 20 or 30 years before you see the true benefits."