Independent public-records tracker. Not a government website.Facts from official state, HHS and SEC filings
BreachRecord

Largest data breaches of 2024

The 7 data breaches first reported in 2024 with the most people affected, using official totals from the filings. Where no official total was filed, the number is the sum of state filings and is labelled "At least". Facts come from official filings with US state attorneys general, the U.S. Department of Health and Human Services (HHS) and the SEC; each breach page links its sources.

Updated Oct 21, 2026 · Showing 1–7 of 7

# Organization First filed People affected Information exposed Filed with
1 Kaiser Foundation Health Plan, Inc.Kaiser Foundation Health Plan, Inc. breach history 13,400,000Official total
  • Medical information
 HHS, California AG
2 A&A Services d/b/a Sav-RxA&A Services breach history 2,812,336Official total
  • Social Security number
  • Medical information
  • Health insurance information
  • +3 more
 Washington AG, HHS, California AG
3 WebTPA Employer Services, LLCWebTPA Employer Services, LLC breach history 2,518,533Official total
  • Medical information
 HHS, California AG
4 Medical Management Resource Group, L.L.C.Medical Management Resource Group, L.L.C. breach history 2,264,157Official total
  • Social Security number
  • Medical information
  • Health insurance information
  • +2 more
 Washington AG, HHS, California AG
5 Signature Performance, Inc.Signature Performance, Inc. breach history 130,228Official total
  • Medical information
 HHS
6 Highland Health SystemsHighland Health Systems breach history 83,543Official total
  • Medical information
 HHS
7 Octapharma Plasma, Inc.Octapharma Plasma, Inc. breach history At least 9,127Sum of state filings
  • Social Security number
  • Medical information
  • Driver's license
  • +3 more
 Washington AG, California AG

Other years

People affected is the official total from a filing, or “At least” the sum of state filings where no total was filed. Spotted an error? Report a correction.