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HHS OCR report ยท 2024

Group Health Cooperative of South Central Wisconsin data breach

Group Health Cooperative of South Central Wisconsin, a health plan in Wisconsin, reported a breach affecting 533,809 individuals to HHS OCR on Apr 8, 2024.

OCR report facts

Covered entity
Group Health Cooperative of South Central Wisconsin
Entity type
Health Plan
State
Wisconsin
Individuals affected
533,809
Submission date
Apr 8, 2024
Type of breach
Hacking/IT Incident
Location of breached information
Network Server
Business associate present
No
Status
Archive (closed)

OCR description

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 t...

Text as published on the HHS OCR breach portal.

Frequently asked questions

How many people were affected by the Group Health Cooperative of South Central Wisconsin data breach?

The report to HHS OCR lists 533,809 individuals affected.

When was it reported to HHS?

It was submitted to HHS OCR on Apr 8, 2024.

What type of breach was it?

The OCR portal lists the type of breach as Hacking/IT Incident, with the breached information located in: Network Server.

Is the investigation still open?

No. The report is in the OCR portal archive, which holds reports where OCR has closed its review.

Is a breach notice letter from Group Health Cooperative of South Central Wisconsin legitimate?

This site cannot verify letters. Check the sender against the organisation's official website and the HHS OCR breach portal, and avoid calling numbers or clicking links only listed in an unexpected message. See our guide on what to do after a data breach notice.

Source: HHS OCR Breach Portal, OCR export October 2026. Network USA is not affiliated with HHS or Group Health Cooperative of South Central Wisconsin.