It's not just that there is a 'moral case' for greater diversity in business. Capitalising on women's potential makes economic sense. Having more women on corporate boards has been shown to increase both the share price and the return on equity. It doesn't surprise me that the 2013 list of the world's most valuable brands showed companies with a greater than average proportion of female board members outperforms those with an all-male board. So why are women undervalued across the business spectrum?