Five senators sent a letter to the head of the Commodity Futures Trading Commission (CTFC) today, calling on him to restrict the trade of oil futures, citing rising gas prices as reason to limit investment.

Sens. Dianne FeinsteinDianne Emiel FeinsteinDems call for action against Cassidy-Graham ObamaCare repeal Feinstein pushes back on Trump’s N. Korea policy Feinstein on reelection bid: ‘We will see’ MORE (D-Calif.), Maria CantwellMaria Elaine CantwellSenate energy bill is misguided gift to Trump’s dirty fossil fuel agenda Help states solve their housing problems with the Affordable Housing Credit Improvement Act Time to pass the U.S. OUTDOOR Act to support American jobs and consumers MORE (D-Wash.), Ron WydenRonald (Ron) Lee WydenSenate Dems hold floor talk-a-thon against latest ObamaCare repeal bill Overnight Defense: Senate passes 0B defense bill | 3,000 US troops heading to Afghanistan | Two more Navy officials fired over ship collisions Finance to hold hearing on ObamaCare repeal bill MORE (D-Ore.), Ted Stevens (R-Alaska), and Olympia Snowe (R-Maine) called on CFTC Chairman Walter Lukken to use emergency powers to prevent futures traders from increasing the size of their investments, and to reduce the holdings of institutional investors, such as banks and investment funds, whose investments exceed certain levels.

The senators wrote that the increasing price of oil futures is driving up the price of gasoline. Futures trading centers on the purchase and sale of oil at future prices, and investors essentially bet on how the price of oil will fluctuate. Over 99 percent of new investors are betting that the price of oil will go up, the senators wrote, resulting in a speculation bubble that has driven up the price of oil.