The corporate research agency Moody’s has downgraded Houghton Mifflin Harcourt’s rating, citing concerns over the company’s “unsustainable capital structure” and $6.8 billion debt. The financial agency cut the company’s rating based on worries about the educational book market, according to the Independent.

Recently, Barry O’Callaghan, chairman of the company’s corporate parent Education Media Publishing Group, took over as CEO of HMH. Earlier this year, that group decided against selling the company’s trade division.

Here’s more from the article: “Moody’s maintains that HMH remains vulnerable to state and local spending in the United States on so-called basal and supplemental K-12 (twelfth grade) educational publications. It says those categories posted a 22.8 percent decline in sales in January 2009.” (Via jafurtado)