Birgit Rausing (Sweden) $13 billion

86. Widowed, 3 children

She and her three children inherited packaging giant Tetra Laval after her husband Gad Rausing died in 2000. The firm revolutionized the storing of liquids, such as juices and milk, by developing lightweight packaging that preserves the nutritional value and taste of products. Birgit is retired in Switzerland. Leaves family business to her children, all three of whom sit on board; Jorn, the youngest, also heads company's mergers and acquisitions division.