According to a regulatory filing Friday, the fund, led by billionaire David Tepper, upped its stake in the SunEdison’s spinoff, TerraForm Power to 10.88% from 9.5%, sending shares of TerraForm up 13%.

The filing comes in conjunction with an ongoing lawsuit from the hedge fund, which started in January as an attempt to block SunEdison (SUNE) from using TerraForm to acquire parts of solar company, Vivint Solar (VSLR) . Appaloosa, which owns a controlling interest in TerraForm, claims that SunEdison had breached fiduciary duties.

On Wednesday, Appaloosa filed an amendment to the lawsuit, calling for the removal of Terraform’s conflicts committee, which judges potential conflicts of interest between TerraForm Power and affiliates such as SunEdison, according to Reuters. The fund is also seeking a new board member to represent shareholder’s interest, as well as “additional related relief.”

After the deal with Vivint Solar fell through in early March, SunEdison rode out several rounds of bad news, including warnings of a possible bankruptcy issued by TerraForm. TerraForm Power’s CEO, Brian Wuebbels, stepped down Thursday, just before Tepper called for his resignation.

SunEdison also revealed Thursday that it had received subpoena from the Justice Department regarding its attempted purchase of Vivint Solar.

Shares of TerraForm have slid 22% year to date, while shares of SunEdison have dropped 91% year to date.

Appaloosa declined Fortune’s request for comment.