Houghton Mifflin Harcourt officially filed for pre-packaged bankruptcy Monday morning, citing debts and liabilities of over $1 billion. The filing is part of a restructuring of its finances that will cut its debt by $3.1 billion largely by having its lenders exchange debt for equity.

The first publicly available filings provide little financial details, other than listing its largest unsecured creditors that include Donnelley, owed $20.3 million, while Donnelley Asia Printing Solutions is owed $5,6 million. Williams Lea, a business processing outsourcing firm, is owed just under $21 million. Other large unsecured creditors include Marshall Cavendish ($6.7 million), Kue Digital Inc. ($4.5 million), and the Bulkley Dunton Publishing Group ($4.1 million. to pursue growth opportunities.

As it said when it first announced plans for the prepackaged filing, HMH issued a statement today that said it “will maintain normal day-to-day business operations throughout the restructuring process, and we expect no disruptions to our relationships with our customers, agents, authors, employees, business partners and suppliers. Additionally, our plan provides for our suppliers and vendors to be paid in full during and after this process and for our employees to continue receiving their usual pay and benefits.

HMH said it still expects to complete the restructuring by the end of June 2012.