Sunnova Energy International Inc., one of the largest US rooftop solar companies, filed for bankruptcy in Texas following struggles with mounting debt and diminishing sales prospects.

Sunnova shares sank 15% in overnight trading.

The company listed $10 billion to $50 billion of both liabilities and assets, according to a court filing.

Sunnova had been negotiating with creditors to fix its capital structure since March, when it issued a going concern warning and cited “stubbornly high interest rates, along with regulatory and political uncertainties” making consumers and capital providers more cautious.

Sunnova also recently terminated most of its $3 billion partial loan guarantee with the US Energy Department, which was intended to help provide panels to low-income customers. In early June, it said it was firing about 55% of its workforce, following the bankruptcy filing of a subsidiary.

The US residential solar industry is reeling from a torrent of headwinds, including high interest rates, rising tariffs on imported equipment and reduced state incentives in California, the nation’s biggest rooftop market. Republicans in the US House have advanced a tax and spending bill that would would end tax credits for companies that lease rooftop systems as well as homeonwers who buy them. If those provisions become law, it would devastate the sector, analysts say.

Sunnova became the second major publicly traded rooftop company to file for bankruptcy in the past year, following SunPower Corp. in August 2024.