To commemorate International Women’s Day on March 8, and celebrate the one-year anniversary of its Gender Diversity Index ETF, State Street Global Advisors is calling upon more than 3,500 companies it invests in “to take intentional steps to increase the number of women on their corporate boards.”

Companies that SSGA, the asset management business of State Street Corporation, invests in on behalf of clients represent more than $30 trillion in market capitalization. As part of the campaign, it commissioned a statue of a young girl, representing the future, installed on Wall Street to face off against its famous bull statue.

“We believe good corporate governance is a function of strong, effective and independent board leadership," said Ron O’Hanley, president and chief executive officer of SSGA, said in a statement. “A key contributor to effective independent board leadership is diversity of thought, which requires directors with different skills, backgrounds and expertise. We are calling on companies to take concrete steps to increase gender diversity on their boards and have issued clear guidance to help them begin to take action.”

O’Hanley detailed the guidance during a keynote speech at the Corporate Governance Symposium, hosted by the University of Delaware’s Weinberg Center for Corporate Governance.

According to a recent study by MSCI, a leading provider of investment decision support tools, companies with strong female leadership generated a return on equity of 10.1 percent per year versus 7.4 percent for those without a critical mass of women at the top, a 36.4 percent increase of average return on equity.

Although there has been some progress made on the inclusion of women on corporate boards, one out of every four Russell 3000 companies do not have even one woman on their board; nearly 60 percent have fewer than 15 percent of their boards comprising women directors.

To accompany its gender equality objectives, SSGA issued guidelines “to drive greater board gender diversity through active dialogue and engagement with company and board leadership.” In the event that a company fails to take action to increase the number of women on its board, SSGA will use proxy voting power to influence change. Among the potential strategies: voting against the chair of the board’s nominating and/or governance committee if necessary.

“As part of our review of boards’ gender diversity, we analyzed and compared the level of diversity in three markets: Australia, the UK and the U.S.,” says Rakhi Kumar, head of corporate governance at SSGA. “Most large cap company boards in these markets have at least one female director but have yet to fully embrace gender equality in their ranks. We believe boards have an important role to play in increasing gender diversity and believe our guidance can help directors take action now.”