[pessimizer]

I would argue that the age of the company isn't what's important, but the age of the CEO. If a 150 year-old company has a 45 year old CEO, what does the age of the company have to do with it - unless you are arguing for long lasting traditions of discrimination that are invariant for a company.

[ps4fanboy]

Large companies tend to have a fair amount of nepotism in the top ranking positions. You would have to control for this as well.

[pessimizer]

Women would benefit from nepotism.

[ps4fanboy]

would? You mean they do? http://en.wikipedia.org/wiki/Gina_Rinehart