Hortensia Herrero

Hortensia Herrero owns nearly 28% of Mercadona, the Spanish supermarket chain she helped build with her husband Juan Roig (also a billionaire).

Herrero, who serves as vice president, was part of the group that bought the company from Roig's father back in 1981, when it had 8 small stores.

Herrero and Roig's four daughters are board members of Mercadona; Roig's brother Fernando is also a shareholder and billionaire.

Mercadona, which is privately owned, has about 1,700 stores, mostly in Spain, and employs 110,000 people.

The company shares 25% of its pretax profit with employees.