Empower Women by Index Membership: Evidence from a Unique Experiment from Japan
6/17/23, 9:00 AM - 6/17/23, 9:30 AM


Yupana Wiwattanakantang
Associate Professor of Finance NUS Business School, SingaporeAssociate professor, Department of FinanceAssociate professor, Department of Finance


Takeo Hoshi

Professor of Economics at the University of Tokyo and research member at ECGI


Paper Authors: Vikas Mehrotra, Lukas Roth, Yusuke Tsujimoto, Yupana Wiwattanakantang

In 2017, Government Pension Investment Fund of Japan (GPIF), the world’s biggest sovereign fund, adopted the MSCI Empowering Women Index (WIN), created by Morgan Stanley. To qualify for the prestigious index membership, firms must meet certain criteria for the advancement of women in their workforce, particularly in the management cadres. Inclusion in the WIN index is structured loosely as a tournament—only the top 50% in each industry category of the MSCI IMI Top 700 firms (roughly corresponding to the S&P 500 in the U.S.) are included. Focusing on firms around the inclusion threshold allows us to employ a difference-in-differences methodology to test for real social effects of the WIN index creation. Firms around the threshold competing for index inclusion show significant improvements in not only women’s participation in the workforce but also in in the Csuite compared to firms farther away from the inclusion threshold. Interestingly, WIN Index firms also display an increase in paternity leaves suggesting a shift into a more women friendly corporate culture. WIN index firms also gain institutional ownership. Overall, the change in corporate social behaviour is not at the expense of lower operating profitability or valuation.

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