SunEdison, once the fastest-growing U.S. renewable energy company, filed for Chapter 11 bankruptcy protection on Thursday as years of debt-fueled acquisitions proved unsustainable. This story is developing. Please check back for further updates.

In its bankruptcy filing, the company said it had assets of $20.7 billion and liabilities of $16.1 billion as of Sept. 30. The company said its two publicly traded subsidiaries, TerraForm Power and TerraForm Global, were not part of the bankruptcy. The company said it secured up to $300 million in new financing from its first-lien and second-lien lenders, which is subject to court approval. The money will be used to support SunEdison's operations during its bankruptcy, such as paying wages and vendors, and proceeding with ongoing projects. "Our decision to initiate a court-supervised restructuring was a difficult but important step to address our immediate liquidity issues," said Ahmad Chatila, SunEdison chief executive officer.



He said the company planned to use Chapter 11 to reduce debt, shed non-core operations and take steps to get the most value out of its technology and intellectual property.

Although solar project developers continue to benefit from robust demand, their shares have been hit by investor concerns that demand could fall in tandem with weak oil prices. Shares of SunEdison were halted, and last traded at about 34 cents on the New York Stock Exchange. The company's stock traded as high as $33.44 in July 2015. Shares of First Solar were up slightly and shares of SolarCity were last up more than 5 percent. An index of solar shares gained 1 percent. Major SunEdison shareholders include OppenheimerFunds with a 11.9 percent stake, BlackRock Inc with a 6.5 percent stake, The Vanguard Group with a 6.4 percent stake and Adage Capital Partners with a 5.4 percent stake, according to court documents. Shareholders generally lose their investment in a bankruptcy.

SunEdison has struggled with a list of problems. Breakneck expansion during 2014 and 2015 left the company saddled with huge debt. Investors began to lose confidence when SunEdison last year launched its biggest deal for Vivint Solar, worth $2.2 billion at the time it was announced. In March, Vivint terminated the cash-and-stock deal after SunEdison failed to close on the planned acquisition. Vivint shares were up more than 6 percent on Thursday. The Vivint deal touched off litigation involving its yieldcos, the listed subsidiaries that own and operate renewable energy assets, some of which were acquired from SunEdison. Billionaire David Tepper's Appaloosa Management sued to prevent TerraForm Power from buying some Vivint assets as part of SunEdison's proposed purchase of the company. Appaloosa is also seeking to overhaul TerraForm Power's Conflicts Committee, claiming the company's controlling shareholder, SunEdison, breached its fiduciary duties.