Investors can change the behavior of companies. But for that, they need information. This week, Bloomberg launched an index that scores financial-service companies on how well they treat women and whether they are promoting gender equality. The index, called the Bloomberg Financial Services Gender-Equality Index (BFGEI), rates companies not only based on programs like parental leave and flexible work arrangements—which together make up 70 percent of the score—but also whether a company has product offerings geared toward women and community engagement.