Houghton Mifflin Harcourt Company
ent_e842014e5a786fa52daa8609
Disclosures
4
Leak Site · State AG · 3 jurisdictions
Multi-filing incidents
1
incidents joining 2+ filings here
Max affected reported
194
nationwide · State AG NH
Leak-site claims
1
unverified actor claims
Identity resolution
- Canonical name
- Houghton Mifflin Harcourt Company
- Normalized
- houghton mifflin harcourt— dedupe via name-norm; Microsoft / MSFT collapse to one row
- GLEIF LEI
- No match
- SEC EDGAR CIK
- None — not an SEC registrant
- Domain
- hmhco.com
Disclosure history (4)newest first
- GLOBALLeak Siteas victim2026-05-09
Your data was compromised in several of our campaigns throughout the past few months. We urge you to engage with us, it is in your best interests. This is a final warning to reach out by 12 May 2026 before we leak along with several annoying (digital) problems that'll come your way. Make the right decision, don't be the next headline. | Updated: 9 May 2026 | Warning: FINAL WARNING PAY OR LEAK
- Massachusetts State AGas victim2020-10-29
Houghton Mifflin Harcourt Publishing Company reported a data breach to the Massachusetts Office of Consumer Affairs and Business Regulation. The breach was reported on 2020-10-29. 5 Massachusetts residents were affected. The report records the breach type as electronic.
- Massachusetts State AGas victim2008-07-02
Houghton Mifflin Harcourt reported a data breach to the Massachusetts Office of Consumer Affairs and Business Regulation. The breach was reported on 2008-07-02. 11 Massachusetts residents were affected. The report records the breach type as electronic.
- New Hampshire State AGas victim2008-07-01
Houghton Mifflin Harcourt (HMH) notified the New Hampshire Attorney General on July 1, 2008, regarding a worldwide Internet-based attack on a non-e-commerce website discovered on April 25, 2008. The incident compromised Social Security Numbers for approximately 194 individuals, including 2 New Hampshire residents. HMH retained digital forensics experts, reported the matter to the U.S. Secret Service and state law enforcement, and arranged for two years of free credit monitoring and identity theft insurance for affected individuals. The investigation was ongoing at the time of filing.