Goldman Sachs' new rule: At least 1 woman on the board or you can't go public

"From a governance perspective, diversity on boards is a very, very important issue," Solomon said in an interview with CNBC at the World Economic Forum in Davos, Switzerland.

Goldman's push for diversity will be focused primarily on women: Over the past four years, initial public offerings of companies in the United States with at least one female director on their boards performed "significantly better" compared to those without, the CEO said.

The initiative will kick off on July 1 in the United States and Europe. By 2021, the bank will look for two diverse board members, Solomon said.

Goldman Sachs itself has four women on its board of directors, out of 11 total members.

The bank did not respond to requests for comment at the time of publishing.