In addition, investors are becoming more wary of investment fees, and the lower fees in passively managed products have helped draw greater investment interest. [Investors Like ETFs’ Low Fees as Active Managers Lag Benchmarks]

“The cloudy economic outlook suggests that this trend may continue,” Leonberger said in the article. “Whether it is a short term uncertainty such as the fiscal cliff or a longer-term matter about the future of a regional currency (Europe), it is conceivable that the market will remain a risk on / risk off trade over the next few years. Therefore, we may see continued flows into passively managed funds in the equity markets.”

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Max Chen contributed to this article.