“Mixed gender teams are beneficial,” said Leah Bennett, vice president of Westwood Trust Houston, which manages $22 billion. “But companies haven’t necessarily been aware of that because there aren’t many women in the field. There’s a lack of knowledge about what mixed-gender teams can do,” said Bennett, who contributed to the research.

Related: New gender pay gap studies are challenging conventional wisdom

It’s not just investors who are unaware of the potential of men and women running money together. In a poll of more than 5,000 members worldwide, CFA Institute found that just 43 percent of male chartered financial analysts said diverse management teams lead to better performance, while 70 percent of similarly qualified women thought it did.

"This difference is interesting since it is more than likely that the women respondents have been in gender diverse groups and have witnessed the benefits firsthand," the report said.

While only 30 percent of investors thought diversity brought better returns, another quarter of investors preferred mixed teams for the sake of fairness. The remaining investors, almost half, thought combining men and women didn’t matter when managing money.

A small but growing minority of clients, particularly public pension funds, are asking their investment managers to disclose diversity statistics, the report says. CalSTRS, the California State Teachers Retirement System, also invested $250 million in an exchange-traded fund created this year to invest in companies with more women at senior levels. Other states and cities, including New York, have programs aimed at developing asset management firms led by women and minorities.

While women make up about 48 percent of business school graduates in the U.S., they account for only about 28 percent of those taking the CFA exam and 16 percent of current CFAs, the report said.

“A lot of women have been self-selecting out of the industry,” says Bennett, citing films such as “The Big Short” and “The Wolf of Wall Street” for giving young women a negative impression of the industry. In fact, she says, areas such as wealth investment and impact investing have a lot of opportunities for women.

“We are asking all of our members to join us in addressing the chronic issue of gender disparity,” said Paul Smith, chief executive officer of the CFA Institute. “The time to end the woeful under-representation of women in the investment management industry is now.”

Women are better represented in many Asian countries, particularly China, where they make up half of those taking the CFA exam, and Vietnam, where they are more than 40 percent.

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