As the head of the multi-billion-dollar Chesapeake Energy Corp., Aubrey McClendon was a big player in the U.S. natural gas market. On the side, McClendon also ran a $200 million hedge fund that traded in the same commodities that Chesapeake produces, according to a Reuters investigation. The expose relied in part on documents first made public by Sen. Bernie Sanders. McClendon held huge positions in natural-gas derivatives, according to the confidential trading data disclosed last year by Sanders. "Speculators, particularly CEOs of major energy companies, should not be allowed to make a fortune by jacking-up oil and gas prices in the energy futures market.  It is time for federal regulators to do their job, obey the law, and crack down on excessive energy speculation," he said.

Under pressure from shareholders, McClendon stepped down as chairman on Tuesday and on Wednesday he apologized to investors.

Read the Reuters article.