Past studies have shown companies with more female directors tend to outperform. Fortune 500 companies with three or more women as directors had an average return on equity of 15.3 percent for the five years ended 2008, according to a 2011 report by Catalyst. That compares with 10.5 percent for companies with no female board members.

“Companies with the best record of promoting women outperformed their competitors by revenue, equity and assets,” said Miyuki Kashima, head of Japanese equity investment at BNY Mellon Asset Management Japan Ltd. “I would expect a similar trend going forward in Japan.”

Companies with at least one female director in Japan delivered a total cumulative return of 108 percent in the three years through Feb. 28, data compiled by Bloomberg show. For firms with all-male boards, the total return was 99 percent.

David Fuller's view

This is such an obvious point and a key to Japan’s long-term future.  When I was last in Japan, a couple of ambitious young women at my seminar told me that they wanted to work for western rather than Japanese companies.  Moreover, they had prepared themselves for this by learning to speak English very competently, which was certainly a sign of their ability and ambition.  OK, that was in 1989 but change has been slow subsequently, although Abe is trying to improve this situation. 

Any western company planning to expand with an office in Japan should hire mostly women, not least in the leading positions.  They will be brighter and better qualified than the remaining men available, and also more loyal.  That is what I discovered when developing a research department in London’s financial district in the 1970s.