Michigan firm sues Chesapeake Energy and Encana Corp.

Filed Friday in U.S. District Court in Michigan, the suit alleges that Chesapeake and Encana competed against each other, driving up prices at a different auction in May 2010, but that the two companies then illegally worked together to divide up the acreage NorthStar sold in an auction one month later, ensuring that both companies received leaseholds for substantially lower prices.

Chesapeake and Encana “conspired to restrain trade and depress prices, willfully violating federal and state antitrust laws, with the primary goal of avoiding and/or preventing competition and thereby artificially lowering the price for or eliminating NorthStar's ability to sell its acreage,” NorthStar said in the lawsuit.

Chesapeake and Encana both have conducted internal investigations into the claims, and each company cleared itself of wrongdoing.

Encana on Monday said it planned to “vigorously defend any lawsuit” related to collusion claims. Chesapeake spokesman Michael Kehs declined to comment Monday.