(Bloomberg) -- Women account for about a quarter of the top executives at S&P 500 companies and they only control about 1% of the value of shares held among their fellow corporate leaders, new research shows.

The disparity means male executives held about $770 billion worth of shares in S&P 500 companies in 2020, compared with about $9 billion for female executives, said Andreas Hoepner, a professor of operational risk, banking and finance at the Smurfit Graduate School of Business at the University of Dublin. The study, conducted with Swedish gender data company ExecuShe, found the ratio was skewed even after removing company founders and outliers like Tesla Inc. Chief Executive Officer Elon Musk, the wealthiest executive in the index, he said.

“We found a giant gender power gap,” Hoepner said in an interview. 

The emergences of the #MeToo movement has resulted in heightened scrutiny and an increase in corporate pledges to mitigate gender pay imbalances and other inequalities in the executive ranks. It remains a work in progress. Women in the U.S. typically make about 83 cents for every dollar a man earns (and that’s just base salary).

As more women get promoted to c-suite jobs, a larger share of their overall compensation comes from equity or stock options, and the disparity with male peers grows. In 2020, women in the top ranks of S&P 500 leadership earned only 75% of male executives, the widest gap in nine years, mostly because of the imbalance in stock ownership, according to analysts at Morningstar Inc. The differences only increase for women of color.

Another reason why women earn less is they tend to have executive roles in departments such as human resources and marketing, where equity ownership levels tend to be lower than for positions such as chief technology officer, Hoepner  said. The reality is there also are far fewer women CEOs, he said.

The study was based on regulatory filings and company Web pages, and the research shows how equity disparities have grown exponentially over time, Hoepner said.

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