After decades of debate on whether indexes outperform portfolio managers, professional investors still embrace active management, especially in times of market uncertainty, according to a new study.

Almost two-thirds of professional investors, or 63 percent, expect an increase in market volatility over the next year—and the same number believe actively managed strategies work best in falling markets, according to the 2015 MFS Active Management Sentiment Study.

"At some point, we will see additional volatility and that creates opportunity for active managers to identify risks and generate alpha," said Joe Flaherty, chief investment risk officer at MFS Investment Management in a prepared statement. "Downside risk management is part of the value proposition that active managers can deliver through research and security selection."

What’s more, respondents in the study are putting their clients’ money where their mouth is, allocating 77 percent of their assets under management to active investment strategies. Over the past 25 years, the top quartile of active managers has added 7.6 percent in excess returns in falling markets, said MFS, citing Morningstar data.

Most respondents, 60 percent, report that actively managed strategies will continue to play “a significant role” in their portfolios in the future, and 68 percent said they will continue to allocate the majority of their assets to active strategies over the next five years, according to the survey.

Just 38 percent of professional investors surveyed are highly confident in passive management, while 52 percent said the same about active management.

The survey found that 70 percent of professional investors list protecting capital in down markets one of the most important attributes when considering an active manager.

The study was conducted between April and June, surveying 1,083 financial advisors, institutional investors and professional buyers globally, including 575 in the U.S.

The survey also found that:

  • Sixty percent of respondents believe passive investments have no ability to adapt in volatile markets.
  • Active risk management was listed as the most important trait of a skilled active manager by 83 percent of respondents. Other important traits included active security selection (67 percent) and robust investment research platform (64 percent).
  • Sixty-eight percent of the professional investors surveyed believe investors are too focused on short-term returns.
  • Eighty-two percent said they would pay more for outperformance over five years, and 68 percent said they would pay more for outperformance over a decade.