Esther Grether

Inherited a beauty and health care products company from her late husband in 1975. Also has a 7.5% stake in watchmaker Swatch, now worth over $900 million. Biggest part of her fortune comes from her collection of 20th century art, which reportedly includes over 600 pieces by such artists as Pablo Picasso, Paul Cezanne, Salvador Dali, Francis Bacon and Alberto Giacometti. Keeps the works in a converted printing factory where she also lives.