Commodity Futures Trading Commission discloses investigation of crude oil contracts

Federal regulators are six months into a wide-ranging investigation of U.S. oil markets, with a focus on possible price manipulation.

The Commodity Futures Trading Commission on Thursday said it started the probe in December and took the unusual step of publicizing it "because of today's unprecedented market conditions."

Crude prices have risen more than 42 percent since early December, even after a decline of more than $4 to $126.62 a barrel on the New York Mercantile Exchange. Gasoline prices are nearing a national average of $4 a gallon (3.8…