US solar energy firm SunEdison has filed for bankruptcy protection after years of rapid-fire acquisitions.
The company's strategy of buying smaller firms to grow its market-share left it with large amounts of debt.
SunEdison is also facing investigations by US regulators.
"Our decision to initiate a court-supervised restructuring was a difficult but important step to address our immediate liquidity issues," said chief executive Ahmad Chatila.
"The court process will allow us to right-size our balance sheet and reduce our debt, providing the opportunity to support the business going forward while focusing on our core strengths," he said.
The company had $18bn (£12.6bn) in liabilities on 31 December according to papers it filed with the US bankruptcy court.
It said it has secured $300m of new financing to use during the bankruptcy process.
Meanwhile, renewable energy firm Ecotricity said it had bought SunEdison's UK rooftop solar business.
Investors have filed legal claims alleging SunEdison misled them about its financial viability. The company has delayed releasing its annual reports twice.
SunEdison is also facing investigations by the US Department of Justice (DoJ) and Securities and Exchange Commission (SEC) over its failed deal to buy Vivint Solar.
The $2.2bn cash-and-stock deal fell through in March, after SunEdison failed to close on the acquisition.