Kindred Health Care, the largest provider of post-acute care services in the U.S., has paid a $3 million penalty for failing to comply with a corporate integrity agreement (CIA) with HHS’s Office of the Inspector General (OIG).

It’s the largest fine ever for a CIA violation, which OIG said was due to the company’s failure to correct improper billing practices in the fourth year of a five-year agreement.

“This penalty should send a signal to providers that failure to implement these requirements will have serious consequences," said HHS Inspector General Daniel Levinson. “We will continue to closely monitor Kindred's compliance with the CIA.”

The specific violation in this case involved Kindred billing Medicare for hospice care for patients who weren’t eligible for such services at the highest level and most highly paid category. OIG said due to these findings, Kindred closed 18 sites it labeled as “underperforming” since March 2015.

The overpayment issues were uncovered by audits required by Kindred’s CIA in 2013, 2014 and 2015. For 2016, OIG said the company “took significant corrective actions, including upgrading internal audits and investigations and tracking resolutions of identified issues.”