A lawsuit has been filed by a large shareholder of Louisville-based Kindred Healthcare that seeks to block the sale of the company to Humana and two private equity firms.

WDRB reports that the suit was filed Thursday in a Delaware state court by New York-based Brigade Capital Management. The company’s funds control about 5.7 percent of Kindred’s stock, according to a U.S Securities and Exchange Commission filing.

It says in the filing that Kindred’s board is breaching its fiduciary duties in approving the sale. Brigade contends the acquisition undervalues the company.

Kindred’s shareholders are scheduled to vote later this month on the deal, worth more than $700 million.

In a statement to WDRB, Kindred said that the lawsuit is without merit and that the sale remains on track to be completed this summer.

This story has been updated. 

Rick Howlett is host of WFPL's weekly talk show, "In Conversation."