Fresenius Medical Care AG, the world’s biggest provider of kidney dialysis, was ordered by U.S. District Judge William J. Haynes to pay treble damages of $38.9 million to settle charges brought by two whistleblowers that the company had overbilled Medicare. The lawsuit claimed two Fresenius-owned companies, Renal Care Group and Renal Care Group Supply Co., overbilled Medicare for home support dialysis supplies between 1999 and 2005, allegedly falsely overbilling 3,979 patients during this period.

Haynes first ordered Fresenius to pay $19.4 million in March 2010. After the company’s appeal was overturned, the government asked the judge to impose treble damages.