Group Health Cooperative of South Central Wisconsin
Disclosed Apr 8, 20242 years ago533,809 affectedConfirmed
The covered entity (CE), Group Health Cooperative of South Central Wisconsin, reported that it was the subject of a ransomware attack that affected the protected health information (PHI) of 533,809 individuals. The PHI involved included names, Social Security numbers, addresses, dates of birth and medial record numbers. The CE notified HHS, the affected individuals, the media, and provided substitute notice. In response to the breach, the CE provided complimentary credit monitoring services to the affected individuals and implemented additional administrative, technical, and security safeguards. Staff were retrained on the requirement to protect and secure PHI.
What is known
| People affected | 533,809 (as reported to HHS) |
|---|---|
| Disclosed | Apr 8, 2024 |
| Attack | Hacking |
| Data exposed | Names, Health |
| Sector | Insurance · US |
| Status | Confirmed |
Sources
| Source | |
|---|---|
| HHS OCR breach report (archive, resolved): Group Health Cooperative of South Central Wisconsin (Health Plan, WI)ocrportal.hhs.gov · Official notice | Official notice |
Notices filed
| Where | Filed | People |
|---|---|---|
| HHS archivetotal | Apr 8, 2024 | 533,809 |
History of this record
- 2026-09-25 · added · backfill source
First seen 2026-09-25 (HHS archive), confirmed by HHS OCR. Record counts are as reported. Not legal advice.
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