LDK Solar Co., the Chinese solar-cell maker that defaulted on its bonds this year, filed for bankruptcy in the U.S. to help carry out restructurings already under way in Hong Kong and the Cayman Islands, Bloomberg News reported yesterday. Xinyu, China-based LDK filed for chapter 15 protection yesterday in Wilmington, Del., listing about $1.13 billion in debt and $510 million in assets as of May 31. Affiliates in the U.S., including LDK Solar Systems Inc., sought protection under chapter 11. “Since 2011, the group’s financial performance has significantly deteriorated,” in part due to overcapacity in the solar-cell market, Tammy Fu, a provisional liquidator for the company in Grand Cayman, said in a court filing. LDK is at least the fourth Chinese solar company in little more than a year that has sought bankruptcy or been forced to restructure its debt. Suntech Power Holdings Co., once the world’s largest solar-panel maker, and Zhejiang Topoint Photovoltaic Co. both filed under chapter 15 this year.