Dynegy Inc.'s affiliate Illinois Power Generating Co. on Dec. 9 filed a prepackaged plan of reorganization under Chapter 11 of the federal bankruptcy code.

Illinois Power Generating, or Genco, filed for Chapter 11 in the U.S. Bankruptcy Court for the Southern District of Texas after receiving enough votes from bondholders in favor of the prepackaged bankruptcy reorganization plan. The bankruptcy filing was expected following Dynegy and Genco's Nov. 7 launch of a restructuring transaction that consisted of an out-of-court offer to exchange $825 million of unsecured debt, support for which was being solicited from bondholders along with the prepackaged Genco reorganization plan.

But the exchange offer was terminated, according to a Dec. 9 filing by Dynegy, "because the requisite participation threshold of 97% of the outstanding principal amount of Genco Notes was not satisfied."

On Oct. 3, Dynegy announced a tentative agreement with a group of Genco bondholders that involves a $615 million reduction in debt at Dynegy in exchange for a cash payment. That payment would be funded by the company's ring-fenced Illinois Power Holdings LLC subsidiary and would not come from Dynegy's balance sheet.

Dynegy subsidiaries Illinois Power Marketing Co. and Dynegy Energy Services LLC are not part of the filing. Genco's Coffeen and Newton plants will continue to run during the bankruptcy proceeding, Dynegy said.