In Japan, income, authority, and prestige are unequally distributed between men and women, even if they share the same occupational level. These inequalities are perceived as an ethical issue because they go against the principle of equal treatment at work. Nowadays, Japanese companies are under growing political and regulatory pressure to increase the hiring, promotion, and empowerment of female employees. In this context, the first equity index that tracks the financial performance of the best Japanese companies in terms of gender (...) diversity performance—the MSCI Japan Empowering Women Index —was launched in 2010. It aims to satisfy the growing demand of investors who want to reduce gender discrimination in Japanese workplaces. This paper compares the financial performance of the WIN stock index to the conventional parent index over the period 2010–2018, offering a unique setting to assess the effects of gender diversity screens on portfolio risk-adjusted performance. Our results are robust to a battery of risk-adjusted performance indicators and clearly indicate that investing in the WIN equity index does not come at a cost compared to investing in its conventional peer. This evidence is expected to reinforce confidence of investors who have an appetite for justice in increasing their investment in financial products that support the participation and the advancement of women in the Japanese workforce. (shrink)