As Goldman Sachs Group Inc. moves to increase diversity on corporate boards, the investment bank isn't extending the initiative to a particularly challenged region: Asia.

Chief Executive Officer David Solomon revealed last week that starting in July the bank won't handle initial public offerings for companies that lack either a female or diverse director.

But the rule applies only to IPOs in the U.S. and Europe. Asia's exclusion is striking, given how common all-male boards are in the region. Other bastions of male dominance, including Latin America and the Middle East, also went unmentioned.