Perhaps this excerpt from a Wiki article (Houghton Mifflin - Wikipedia, the free encyclopedia
) might explain most of that debt (on the assumption that the company borrowed heavily to find the money to buy those ex-Reed Elsevier divisions and that those divisions already had debt of their own):
On December 22, 2006, it was announced that Riverdeep PLC had completed its acquisition of Houghton Mifflin. The new joint enterprise would be called the Houghton Mifflin Riverdeep Group. Riverdeep paid $1.75 billion in cash and assumed $1.61 billion in debt from the private investment firms Thomas H. Lee Partners, Bain Capital Partners and The Blackstone Group. Tony Lucki, a former non-executive director of Riverdeep, will remain in his position as Houghton Mifflin's chief executive officer. |
On July 16, 2007 Houghton Mifflin Riverdeep announced that it signed a definitive agreement to acquire the Harcourt Education, Harcourt Trade and Greenwood-Heinemann divisions of Reed Elsevier for $4 billion.