HHS OCR report ยท 2025
Marshfield Clinic Health System data breach
Marshfield Clinic Health System, a healthcare provider in Wisconsin, reported a breach affecting 35,952 individuals to HHS OCR on Nov 7, 2025.
OCR report facts
- Covered entity
- Marshfield Clinic Health System
- Entity type
- Healthcare Provider
- State
- Wisconsin
- Individuals affected
- 35,952
- Submission date
- Nov 7, 2025
- Type of breach
- Hacking/IT Incident
- Location of breached information
- Business associate present
- No
- Status
- Under investigation
Frequently asked questions
How many people were affected by the Marshfield Clinic Health System data breach?
The report to HHS OCR lists 35,952 individuals affected.
When was it reported to HHS?
It was submitted to HHS OCR on Nov 7, 2025.
What type of breach was it?
The OCR portal lists the type of breach as Hacking/IT Incident, with the breached information located in: Email.
Is the investigation still open?
Yes. The OCR portal lists this report as under investigation.
Is a breach notice letter from Marshfield Clinic Health System 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 Marshfield Clinic Health System.