Elaine Tettemer Marshall

70-year-old Dallas resident controls almost 15 percent of Koch Industries Inc., the second-largest closely held company in the U.S. Her stake in the Wichita, Kansas-based industrial conglomerate, which generates annual sales of $110 billion, is worth more than $12.7 billion, according to the Bloomberg Billionaires Index, which has expanded to 100 names. Marshall, who gained control of the Koch stake following the death of her husband, E. Pierce Marshall, in 2006, has never appeared on an international wealth ranking, although her estate has been at the center of two U.S. Supreme Court cases involving her much younger mother-in-law, Anna Nicole Smith. Marshall's ability to stay out of the limelight stands in contrast to her father-in-law, J. Howard Marshall, who had been a Koch shareholder for more than two decades and created a spectacle with his 1994 marriage to Smith, then a 26-year-old Playboy model, whom he wed at age 89. Since then, the Marshall fortune has been in a near-constant state of turmoil. Marshall succumbed to an infection in 2006 at age 67; Smith died of a drug overdose at age 39 in a Florida hotel in 2007. The partnership between the Koch and Marshall families began in 1959, when Koch Industries founder Fred C. Koch acquired a 35 percent stake in Great Northern Oil Co., a Minnesota-based refinery co-founded by Howard Marshall, for about $5 million in cash. In 1974, at the wedding reception of his oldest son, J. Howard Marshall III, the elder Marshall gave each of his two sons 4 percent of Koch Industries voting stock. Pierce Marshall transferred his Koch stake, held by a company called Trof Inc., into a Grantor Retained Annuity Trust (GRAT) named Staurolite. Marshall owned all of Trof, according to the 2002 District Court ruling. Trof held 14.6 percent of Koch Industries, according to a 2001 application to the Federal Communications Commission, which was submitted by a company in which a Koch subsidiary held an interest. Marshall is one of nine Koch Industries board members. She is credited with the family's Koch stake because of her control over the EPM Marital Income Trust.