Federal regulators said that they would place stricter limits on foreign exchanges that trade American oil as concerns continue to grow about the role of speculation in rising fuel prices.

The escalating hostility in Washington toward financial speculators is starting to worry people with knowledge about how commodity markets work.

The escalating hostility in Washington toward financial speculators is starting to worry people with knowledge about how commodity markets work.

The escalating hostility in Washington toward financial speculators is starting to worry people with knowledge about how commodity markets work.

The regulators will look more closely at investors to determine whether they are evading market limits on speculation and artificially driving up world food prices.

The regulators will look more closely at investors to determine whether they are evading market limits on speculation and artificially driving up world food prices.

Upcoming changes set by the chief regulator of the nation’s commodity markets are meant to address concerns that market malfunctions may be contributing to rising food and energy prices.

Federal regulators said that they have been investigating oil and derivative markets for six months to look into potential price manipulation.

Members of Congress have joined the antispeculation bandwagon blaming speculators for high oil prices and have proposed legislation to curb energy trading.

The legislation would be aimed at speculators and other investors who use commodities like oil as a way to hedge against swings in other investment instruments.