WASHINGTON -- Two economists at the St. Louis Federal Reserve have published findings that indicate that Wall Street speculation is responsible for 15 percent of the increase in oil prices over the past decade, a finding with significant implications for the recent sharp rise in gas prices.

While politicians have little ability to alter the price swings of commodities like oil, regulators have both the authority and policy tools to do so. The Commodity Futures Trading Commission is responsible for overseeing the financial market for oil. The 2010 Wall Street reform bill gave the CFTC new power to limit excessive speculation, but the rule will not go into effect until later this year.

According to St. Louis Fed economists Luciana Juvenal and Ivan Petrella, speculation in oil markets was the second-biggest factor behind the past decade's price run-up, behind increased global demand for oil, which accounted for 40 percent of the increase.

"Speculation was the second-largest contributor to oil prices and accounted for about 15 percent of the rise," the economists wrote. "The effect that speculation had on oil prices over this period coincides closely with the dramatic rise in commodity index trading -- resulting in concerns voiced by policymakers."

Commodity indexes allow speculators to bet on the price of several commodities at once, and have become very popular investment tools for both Wall Street investment companies and pension funds. Between 2004 and 2008, the total volume of trading activity in commodity indexes jumped from $13 billion to about $260 billion, according to research by Michael Masters, founder of Masters Capital Markets and the financial reform nonprofit Better Markets.

Masters and others have noted that speculation can exaggerate price swings otherwise dictated by fundamental supply-and-demand dynamics, and can also force prices to move contrary to supply-and-demand predictions. During 2008, when oil prices soared to their highest level on record, they did so during a period in which global demand was low and global supply was high -- what should have been a recipe for lower prices.

The most recent Fed study concludes that economic fundamentals are still the primary determinant, saying only that speculation can "exacerbate" price swings.

"Global demand remained the primary driver of oil prices from 2000 to 2009," Juvenal and Petrella wrote. "That said, one cannot completely dismiss a role for speculation in the run-up of oil prices of the past decade. Speculative demand can and did exacerbate the boom-bust cycle in commodity prices. Ultimately, however, fundamentals continue to account for the long-run trend in oil prices."

Fuel prices are currently at the highest level on record for the month of March, a phenomenon upon which presidential candidates are seizing to attack President Barack Obama on the issue at campaign stops. The financial reform bill Obama signed into law in 2010 allowed the CFTC to write its new rule, designed to curb price movements influenced by excessive speculation. The rule limits the size of the bets that individual traders can make on any given commodity.