William Koch sells carbon, another ingredient to steel.

Litigious brother of Charles and David Koch - he is David's twin - William Koch formed his own carbon company after selling his stake in Koch Industries for $470 million in 1983. More recent setback: In 2015, a judge in Texas ordered him to pay $1.8 million for breeding valuable Japanese Akaushi cattle into the herd at his Wild West-themed Colorado ranch (although that was considerably less than the $23 million jury verdict in the case). Elsewhere in the state, he's got his Castle Creek ranch in Aspen on the market for $80 million.