Ranking number 93 on the Forbes 400 with an estimated fortune of $4.9 billion, Rowling is the co-founder of TRT Holdings, which owns Gold's Gym and Omni Hotels. Father founded Tana Oil & Gas 1980. Robert practiced tax law for one year; defected to father's firm 1981. Duo merged Tana's production properties with Texaco (now Chevron) 1989; received $480 million in cash and stock. Bought Omni Hotels for $500 million in 1996. Three years later sold rest of Tana to Unocal. Last year traded in half of his Chevron shares for cash and oil and gas fields. Stake in Omni Hotels still largest piece of fortune. Other holdings: Gold's Gym, Mexican retailer Waldo's. In July paid $140 million for 14% stake in Nashville hotel and concert company Gaylord Entertainment.