A North American unit of France's Total SA (NYSE: TOT) and a trader agreed to pay $3.6 million to settle charges of attempted manipulation of the U.S. natural gas market, the U.S. Commodity Futures Trading Commission (CFTC) said on Dec. 7.

Total Gas & Power North America Inc. and Therese Tran, formerly known as Therese Nguyen, settled charges of attempted manipulation of monthly index settlement prices at four major trading hubs in Texas and elsewhere in the southwest during monthly settlement periods, the CFTC said.

In addition to the CFTC, the U.S. Federal Energy Regulatory Commission (FERC) said in September that it was investigating similar allegations against Total.

The cases are the latest in which federal regulators have focused on so-called "loss leader" or leveraged trading strategies, where traders seek to lose money in one market to benefit larger positions in a benchmark or other financial index.

In recent years, FERC has alleged similar violations by JPMorgan Chase & Co., which paid $285 million in fines in 2013, as well as Barclays Plc and BP Plc (NYSE: BP), which are still fighting the FERC allegations against them.