Sustainable investing is rapidly becoming part of the global investment mainstream. Many large institutional asset owners have embraced it, as have, to varying degrees, most of the world’s largest asset managers. As of September 2016, 1,055 asset managers had signed the UN-backed Principles for Responsible Investment, committing themselves to incorporating sustainability issues into their investment processes. Large numbers of investors, particularly two groups that are becoming more prominent—women and millennials—consistently indicate they are highly interested in sustainable investing. It is estimated that these emerging investor groups could soon control upwards of $30 trillion in assets in the United States alone.