Breach filing
ArchivedMedical Management Resource Group, L.L.C.: 2,264,157 individuals, Feb 2024.
Medical Management Resource Group, L.L.C. reported a breach of unsecured protected health information to the HHS Office for Civil Rights on 6 February 2024. The filing records the organisation as a business associate in Arizona and lists 2,264,157 individuals affected, which makes it the 2nd largest of the 164 Arizona filings on the register and the 11th largest of the 741 filings submitted nationally in 2024. Among the 16 Arizona filings made in 2024 it ranks 1st.
Individuals affected
2,264,157
As reported to HHS
Modelled cost (IBM 2025)
$362M
Upper bound, method shown
Rank in AZ
2nd
of 164 Arizona filings
Rank in 2024
11th
of 741 filings nationally
Section F.1 / The filing
As posted by HHS OCR
Every value below is the portal's own field for this filing, plus its rank within the register.
- Covered entity type
- Business Associate
- Individuals affected
- 2,264,157
- Breach submission date
- 6 February 2024
- Submission year
- 2024
- Type of breach
- Hacking/IT Incident
- Location of breached information
- Network Server
- Business associate present
- Yes
- State
- Arizona (AZ)
- Portal status
- listed in the HHS OCR breach portal archive
- Rank in Arizona by size
- 2nd of 164
- Rank in 2024 nationally
- 11th of 741
- Arizona median filing
- 3,146 individuals
- Register id (derived)
- AZ-20240206-medical-management-resource-group
Section F.2 / In context
Where this filing sits in Arizona and in 2024
OCR classifies the incident as a hacking or IT incident, with the breached information held in a network server. Hacking/IT Incident is the type recorded on 94 of the 164 Arizona filings (57%) and on 83% of all filings submitted in 2024. Network Server appears on 43% of Arizona filings.
A business associate is recorded as present on the filing, as it is on 21% of Arizona filings. At 2,264,157 individuals the breach is 720 times the Arizona median filing of 3,146 and 566 times the national median of 4,000 across all 7,884 filings. It is one of 149 filings on the register of one million or more individuals.
As of 28 August 2026 the case is listed in the HHS OCR breach portal archive. OCR's closing summary of the case is reproduced in full below.
Arizona's breach notification statute (A.R.S. 18-551, 18-552) requires notice to affected residents within 45 days after determining a breach occurred. Its attorney general threshold: more than 1,000 Arizona residents (AG and Dept. of Homeland Security). The HIPAA Breach Notification Rule ran alongside it: notice to affected individuals and to HHS without unreasonable delay and no later than 60 days after discovery, which is the clock that put this filing on the portal.
Multiplying 2,264,157 individuals by IBM's $160 customer-PII cost per record (Cost of a Data Breach 2025, the figure the site's calculator uses) gives a modelled $362M; the 2026 edition's $192 gives $435M. Both are modelled estimates with the method shown, not costs disclosed by Medical Management Resource Group, L.L.C.. Because the filing is above the roughly 100,000-record range in which the per-record figure is reliable, the result is an upper bound, not an estimate: fixed costs are spread across far more records at this scale.
Section F.3 / OCR closing summary
The portal's archived description, in full
Written by the Office for Civil Rights when the case was closed and reproduced verbatim from the HHS export.
The business associate (BA), Medical Management Resource Group, reported that it experienced a cyber-attack that affected the protected health information (PHI) of 2,264,157 individuals. The PHI involved included names, dates of birth, addresses, diagnoses, medications, and claims and financial information. The BA notified HHS, affected individuals, and the media. In response to the breach, the BA provided complimentary credit monitoring services and implemented new technical safeguards.
Section F.5 / Modelled cost
2,264,157 individuals through IBM's per-record figures
Modelled cost / method shown, not a disclosed cost
Upper boundIBM 2025 customer PII, $160 per record
$362M
2,264,157 x $160
IBM 2026 customer PII, $192 per record
$435M
2,264,157 x $192
Method: individuals affected, as reported by Medical Management Resource Group, L.L.C. to HHS, multiplied by IBM's customer-PII cost per record (Cost of a Data Breach 2025 Figure 6 and the 2026 edition). No cost has been disclosed by the entity for this filing; the figure is a planning estimate, not a fact about the breach. IBM's per-record figures come from mid-volume breaches and IBM cautions against applying them to breaches involving millions of records; the site's per-record page explains where the multiplication holds and where it breaks down.
Context: IBM's average cost of a healthcare breach is $6.64M in the 2026 report ($7.42M in 2025); the global average across all sectors was $4.44M in 2025.
Cost per record: method and limits / Healthcare breach cost, IBM 2026
Section F.6 / Notification clock
Arizona statute and the HIPAA rule
State notification statute
Arizona: A.R.S. 18-551, 18-552
- Notice to individuals
- Within 45 days after determining a breach occurred
- Attorney general threshold
- More than 1,000 Arizona residents (AG and Dept. of Homeland Security) (Within the same 45-day window)
- Private right of action
- No: Only the Arizona Attorney General may enforce
- Penalty
- Up to $10,000 per affected individual, capped at $500,000 per breach, under the Consumer Fraud Act
The HIPAA Breach Notification Rule runs alongside the state statute: notice to affected individuals and to HHS without unreasonable delay and no later than 60 days after discovery.
Section F.7 / Peer filings
Arizona filings closest in size
Neighbours by size rank among Arizona filings in 2024, topped up from other years where 2024 has too few. Filings of 10,000 or more link to their own page.
| Covered entity | Type | Individuals | Submitted | Breach type | Location | BA |
|---|---|---|---|---|---|---|
| Banner Health | Healthcare Provider | 3,620,000 | 3 Aug 2016 | |||
| OnePoint Patient Care | Healthcare Provider | 1,741,152 | 14 Oct 2024 | |||
| SimonMed Imaging | Healthcare Provider | 1,275,669 | 27 Mar 2025 | |||
| Magellan Health Inc. | Health Plan | 1,013,956 | 12 Jun 2020 | |||
| Ciox Health LLC, d/b/a Datavant GroupOpen | Business Associate | 320,702 | 7 Oct 2024 |
Index / Companion schedules
13 HHS breach register
→Hub: every filing, by state, year and entity.
04 Biggest breaches
→Mega-breaches with primary-source cost figures.
Industry / Healthcare
→IBM 2026: $6.64M average, 13 years at #1.
Regulation / HIPAA penalties
→OCR enforcement tiers and the 60-day rule.
11 50-state laws
→Deadline, AG threshold and penalties per state.
Cost / Per record
→Where the per-record model is reliable.
Provenance
Source: U.S. Department of Health and Human Services, Office for Civil Rights, Breach Portal (breaches affecting 500 or more individuals), retrieved 2026-08-28. Public domain. Individuals affected and dates as reported by the covered entity.
Portal: ocrportal.hhs.gov breach report. Statutory basis: HITECH Act section 13402(e)(4): the Secretary must post a list of breaches of unsecured protected health information affecting 500 or more individuals. Breaches affecting fewer than 500 individuals are reported to OCR annually and are not posted, so they are not on this register. Status wording follows the portal's two tabs ("Cases Currently Under Investigation" and "Archive") as of 28 August 2026; a filing moves to the archive when OCR closes the case. Modelled costs on this site are a method applied to the reported count, using IBM Cost of a Data Breach per-record figures, and are never a cost disclosed by the entity. This row: hhs-breach-archive__2026-08-28.csv, export row 1198.
Corrections: if you represent a listed entity and the portal row has been amended, email [email protected] with the portal entry and we will re-pull the export.