Susan Klatten may have been a billionaire for a little longer than most of our list, but she's still not at retirement age, and so she qualifies! Almost every woman we've seen so far has received their money from one specific source or industry; Klatten's cash comes from two.
Klatten's parents owned the chemical giant Altana AG. When they passed away, she and her brother inherited fifty percent each of the business. She must have enjoyed doing business with her brother because the two also own nearly half of the luxury car company BMW. Under her leadership, Altana has become a private company, and she's bought out her brother to take complete control of the firm and add to her $20bn net worth. All that money means she has a lot of spare cash to invest with, and so she's taken on shares in green power companies and graphite production. She's a busy woman!