Dittmer TomTom Dittmer was raised in Sioux City, Iowa, and is a graduate of the University of Iowa. Dittmer is a retired commodities brokerage executive. He retired as chairman of Refco Group in 1999, a firm he cofounded. Under his leadership, Refco was ne of the first US futures firms to build an international presence. In 2006, Dittmer was inducted into the Futures Industry Association Futures Hall of Fame. He lives with his wife in Los Olivos, California. Read More Read Less