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"The asset class does play a role. It's not just bad manager performance," said Joanna Pratt, vice president of financial markets at Nerd Wallet, a financial markets and investing information site. "You really can't know ahead of time what those bad asset classes are doing to be in the next five to 10 years, so it's really important to have a diversified portfolio."
Nerd Wallet listed what it considers to be the 12 worst-performing mutual funds based on fees and performance. They are (with five-year annualized returns and net expense ratios):
- Oppenheimer Commodity Strategy Total Return, -14.61 percent, 2.12 percent.
- Rydex Inverse Government Long Bond Strategy, -13.7 percent, 2.4 percent.
- Ivy Global Natural Resources Fund, -12.6 percent, 2.2 percent.
- Rydex Inverse S&P 500 Strategy, -12.06 percent, 2.42 percent.
- Federated Prudent Bear, -10.48 percent, 2.5 percent.
- DWS Gold & Precious Metals, -10.16 percent, 2.03 percent.
- ALPS/Red Rocks Listed Private Equity, -9.45 percent, 3.28 percent.
- Goldman Sachs Emerging Markets Equity, -8.84 percent, 2.51 percent.
- DWS Latin America Equity, -8.74 percent, 2.53 percent.
- Dreyfus Emerging Markets, -8.42 percent, 2.57 percent.
- Rydex Precious Metals, -8.27 percent, 2.26 percent.
- AllianceBernstein International Value, -8.07 percent, 2.17 percent.
Most of the funds on the list are not rated by Morningstar.
But the Goldman fund actually carries three stars, the AllianceBernstein and Oppenheimer funds have two stars, and the Ivy and ALPS funds each have one star.
So not everyone views performance the same way.
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Pratt said investors should take a hard look at expense ratios and consider that most active managers do not achieve basic market returns.
"Statistically, active managers tend to underperform the index," Pratt said. "Over the past 10 years, only 24 percent of actively managed funds outperformed the index, and they tend to charge higher fees. We would just caution investors when looking to pay higher expense ratios that the math just doesn't support that."
Mutual fund investing still dominates but has been on the decline over the past several years as exchange-traded funds have surged in popularity and now hold $1.5 trillion in assets under management.
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ETFs track indexes and are traded like stocks, making them more liquid than mutual funds. They carry much lower costs and have tax advantages as well.
While the ETFs carry dangers as well—because they can be traded, they also can be volatile—Pratt said passive management is deservedly gaining popularity over active.
"Every once in a while there's a Warren Buffett out there who outperforms year after year," she said. "But you really can't pick those in advance."
- By CNBC.com's Jeff Cox. Follow him on Twitter at @JeffCoxCNBCcom.