Some in the U.S. government are going after those who scheme to artificially drive up the price of oil and oil futures.

Several congressional proposals aimed at limiting trading of oil futures, which analysts say have increased the cost of diesel and other fuel as much as 50 percent. Elected officials have introduced a flurry of bills aimed at closing the “Enron loophole,” which allowed overseas trading of U.S. oil and preceded huge increases in oil speculation during the past five years.

Congress should be doing all it “possibly can to address oil and energy prices,” said Rod Nofziger, OOIDA’s director of government affairs from the Association’s Washington, DC, office.

“There is plenty of evidence to indicate that excessive speculation in the energy futures market has, at least to some extent, contributed to major increases in oil prices over the last few years,” Nofziger said. “While there is always the risk of going too far with good intentions and making the market worse for oil prices, I think the latest proposals to rein in speculation make a lot of sense.”

Congress isn’t the only government branch concerned by oil futures manipulation.

In late July, the U.S. Commodity Futures Trading Commission filed a civil suit against Optiver Holding, alleging that the company manipulated the prices of crude oil and gasoline during 11 days in 2007 by “bullying” the price of oil upward to sell it at or near the close of the day’s trade.

“The Defendants’ intent is well documented by their own e-mails and phone recordings which discuss their efforts to ‘hammer,’ ‘influence,’ ‘push,’ ‘move,’ ‘whack,’ and ‘bully’ the prices of futures contracts in crude oil, heating oil and New York Harbor Gasoline,” the suit states.

Optiver Holding, an Amsterdam-based proprietary trading fund with offices in the U.S., made more than $1 million by such manipulation, according to court documents.

The civil suit names Optiver US, based in Chicago, Optiver VOF of Amsterdam and three corporate officers, including Bastiaan van Kempen, CEO of Optiver US.

In 2000, Congress approved the so-called “Enron loophole,” which allowed for energy commodity trading to be done in markets without government regulation, such as overseas trading.

Oil futures trading doesn’t require traders to ever own any of the actual commodity, and investors often need to possess only 5 percent of the amount they’re trading, as opposed to 50 percent required in general stock trading.

The Commodity Futures Trading Commission, which is charged with regulating futures trading, asked the court to help them regulate the industry.

“Unless restrained and enjoined by this court, there is a reasonable likelihood that defendants will continue to engage in the acts and practices alleged in this complaint or similar acts and practices,” the suit states.