A federal appeals court has cleared Mayer Brown of a proposed class action accusing the firm of negligence and malpractice over a mistake made in 2008 in connection with a $1.5 billion loan extended by JPMorgan & Co. to General Motors Corp.

Ruling on Wednesday, the U.S. Court of Appeals for the Seventh Circuit found that Mayer Brown couldn't be held liable for putative class claims brought against the firm by a group of pension funds that participated in the GM loan as syndicate lenders.

“This appeal began with a $1.5 billion (with a “b”) mistake in documenting a commercial transaction. The central question is who might be held legally responsible for that mistake,” Judge David Hamilton wrote in the opening of his opinion for a three-judge panel. “We agree … that Mayer Brown did not owe a duty to plaintiffs.”