The Largest Healthcare Data Breaches (Ranked)
The 250 largest healthcare data breaches on record, ranked by number of individuals affected.
Marriott International, Inc. — 500,000,000 affected (OR, 2018)Change Healthcare, Inc. — 192,700,000 affected (MN, 2024)Change Healthcare Inc. — 192,700,000 affected (TX, 2025)Equifax Inc. — 143,000,000 affected (OR, 2017)Dental Care Alliance, LLC (Supplemental) — 66,221,300 affected (DE, 2020)Conduent Business Services, LLC (revised submission) — 62,486,662 affected (TX, 2026)Conduent Business Services LLC — 62,224,658 affected (NJ, 2025)AT&T Inc. — 51,226,382 affected (OR, 2024)Comcast Cable Communications LLC — 35,879,455 affected (OR, 2023)Zoosk, Inc — 24,200,000 affected (OR, 2020)Aflac Incorporated — 22,653,844 affected (TX, 2025)CafePress Inc. — 22,000,000 affected (OR, 2019)Cerner Corporation — 18,565,730 affected (TX, 2026)Financial Business Consumer Solutions (Second Supplement) — 17,099,505 affected (DE, 2024)loanDepot.com, LLC — 16,924,071 affected (OR, 2024)ClearVoiceResearch.com, LLP — 15,700,000 affected (OR, 2021)DentaQuest, LLC — 15,000,000 affected (TX, 2026)Nationstar Mortgage LLC (dba Mr. Cooper) — 14,690,284 affected (OR, 2023)Morgan Stanley — 14,256,250 affected (OR, 2020)Aflac Incorporated (“Aflac”) — 13,924,906 affected (GA, 2025)Kaiser Foundation Health Plan, Inc. — 13,400,000 affected (OR, 2024)Prosper Marketplace, Inc. — 13,076,476 affected (OR, 2025)Prosper Marketplace, Inc — 13,076,476 affected (TX, 2025)Nationstar Mortgage LLC (dba Mr. Cooper) — 12,152,023 affected (DE, 2023)Armor Games Inc. — 11,000,000 affected (OR, 2019)Conduent Business Services, LLC — 10,515,849 affected (OR, 2025)Managed Care of North America, Inc. (MCNA) — 8,923,662 affected (OR, 2023)Retrieval-Masters Creditors Bureau, Inc. (d/b/a/ American Medical Collection Agency) — 7,651,395 affected (OR, 2019)Dave, Inc. — 7,500,000 affected (OR, 2020)Zoetop Business Co. Ltd. — 7,341,382 affected (OR, 2020)AssuranceAmerica Managing General Agency, LLC — 6,998,886 affected (TX, 2026)AssuranceAmerica Managing General Agency, LLC — 6,998,886 affected (OR, 2026)TriZetto Provider Solutions — 6,974,232 affected (TX, 2026)Episource, LLC — 6,725,572 affected (CA, 2025)Episource, LLC — 6,725,572 affected (TX, 2026)Episource, LLC — 6,584,876 affected (OR, 2025)Shein — 6,420,000 affected (OR, 2018)Jambav Inc — 6,100,000 affected (OR, 2019)Infosys McCamish Systems, LLC — 6,078,263 affected (OR, 2024)Carnival Corporation — 5,995,277 affected (OR, 2026)Carnival Corporation — 5,995,277 affected (TX, 2026)700Credit, LLC — 5,836,521 affected (TX, 2025)700Credit, LLC — 5,836,521 affected (OR, 2025)PharMerica Corporation — 5,815,591 affected (OR, 2023)Infinity Insurance Company — 5,724,732 affected (OR, 2021)Ascension Health — 5,599,699 affected (OR, 2024)Ascension Health — 5,466,931 affected (OR, 2025)Episource, LLC — 5,418,866 affected (OR, 2025)TMX Finance Corporate Services, Inc., on behalf of itself, its parent TMX Finance LLC & affiliates — 4,895,817 affected (OR, 2023)TMX Finance Corporate Services, Inc., on behalf of itself, its parent TMX Finance LLC & affiliates — 4,822,580 affected (OR, 2023)Colorado Department of Health Care Policy & Financing — 4,662,668 affected (OR, 2024)TransUnion LLC — 4,461,511 affected (TX, 2025)TransUnion LLC — 4,461,511 affected (OR, 2025)The Neiman Marcus Group, LLC (“NMG” or the “Company”) — 4,354,346 affected (OR, 2021)HealthEquity, Inc. — 4,300,000 affected (UT, 2024)HealthEquity, Inc. — 4,300,000 affected (OR, 2024)Minted, LLC — 4,280,000 affected (OR, 2020)Independent Living Systems, LLC — 4,226,508 affected (OR, 2023)ACTIVEOutdoors — 4,210,850 affected (OR, 2016)Johnson & Johnson Health Care Systems Inc. (“Janssen”) — 4,142,215 affected (OR, 2023)VeriSource Services Inc. — 4,052,972 affected (OR, 2025)Reventics, LLC — 3,900,000 affected (OR, 2023)Perry Johnson & Associates, Inc. (PJ&A) — 3,891,565 affected (OR, 2023)Medtronic Inc. — 3,834,294 affected (TX, 2026)Medtronic Inc. — 3,834,294 affected (OR, 2026)Receivables Performance Management LLC — 3,766,573 affected (OR, 2022)Regal Medical Group, Inc. (“RMG”) — 3,685,626 affected (OR, 2023)Banner Health — 3,623,140 affected (OR, 2016)Oregon Department of Transportation — 3,500,000 affected (OR, 2023)University of Phoenix, Inc. — 3,489,274 affected (TX, 2025)University of Phoenix, Inc. — 3,489,274 affected (OR, 2025)Newkirk Products, Inc. — 3,466,120 affected (OR, 2016)LiveAuctioneers, LLC — 3,463,544 affected (OR, 2020)Wolf Haldenstein Adler Freeman & Herz LLP — 3,445,537 affected (OR, 2025)TriZetto Provider Solutions — 3,433,965 affected (OR, 2026)TriZetto Provider Solutions — 3,433,965 affected (MO, 2026)DISA Global Solutions, Inc. — 3,332,750 affected (OR, 2025)20/20 Eye Care Network, Inc. — 3,253,822 affected (OR, 2021)Equifax, Inc. — 3,243,664 affected (WA, 2017)Texas Parks and Wildlife — 3,187,000 affected (TX, 2026)Change Healthcare Inc. — 3,121,209 affected (WA, 2024)Dominion Dental Services, Inc., Dominion National Insurance Company, and Dominion Dental Services US — 3,119,635 affected (OR, 2019)QualDerm Partners, LLC — 3,117,874 affected (TX, 2026)QualDerm Partners, LLC — 3,117,874 affected (TN, 2026)QualDerm Partners, LLC — 3,117,874 affected (OR, 2026)Comcast Cable Communications LLC — 3,100,608 affected (WA, 2023)Columbia University — 3,067,242 affected (TX, 2026)Healthcare Interactive, Inc. — 3,056,950 affected (OR, 2026)TaskRabbit, Inc. — 3,030,925 affected (OR, 2018)Brightly Software, Inc — 2,964,292 affected (OR, 2023)PIH Health, Inc. — 2,947,264 affected (CA, 2025)The Lash Group, LLC — 2,916,417 affected (OR, 2024)Acadian Ambulance Service, Inc. — 2,896,985 affected (LA, 2024)A&A Services, d/b/a Sav-Rx — 2,812,336 affected (OR, 2024)Acadian Ambulance Service, Inc. — 2,783,676 affected (OR, 2024)Elephant Insurance Services, LLC — 2,762,687 affected (OR, 2023)ESO Solutions, Inc. — 2,700,000 affected (OR, 2023)Genworth North America Corporation — 2,700,000 affected (OR, 2023)Navia Benefit Solutions, Inc. — 2,697,540 affected (OR, 2026)Navia Benefit Solutions, Inc. — 2,697,540 affected (TX, 2026)DaVita Inc. — 2,689,826 affected (CO, 2025)Change Healthcare, Inc. — 2,688,358 affected (SC, 2024)Veradigm LLC — 2,672,036 affected (IL, 2025)Veradigm LLC — 2,672,036 affected (OR, 2025)Veradigm LLC — 2,672,036 affected (TX, 2025)Atrium Health (formerly Carolinas HealthCare System) — 2,652,537 affected (OR, 2018)Harvard Pilgrim Health Care — 2,550,922 affected (OR, 2023)Lakeview Loan Servicing, LLC — 2,537,261 affected (OR, 2022)Nacogdoches Memorial Hospital n — 2,507,073 affected (TX, 2026)Nelnet Servicing, LLC — 2,501,324 affected (OR, 2022)Norton Healthcare Inc — 2,500,000 affected (OR, 2023)Health Net Health Plan of Oregon/ Trillium Community Health Plan — 2,500,000 affected (OR, 2021)Equifax, Inc. — 2,419,033 affected (SC, 2017)Forefront Management, LLC and Forefront Dermatology, S.C. — 2,417,984 affected (OR, 2021)Pension Benefit Information, LLC (PBI) — 2,373,076 affected (OR, 2023)Advance Stores Company, Incorporated — 2,316,591 affected (OR, 2024)Medical Management Resource Group, L.L.C., d.b.a. American Vision Partners (“MMRG”) — 2,264,157 affected (OR, 2024)Ahold Delhaize USA Services, LLC — 2,242,521 affected (OR, 2025)Connexin Software, Inc. — 2,216,365 affected (OR, 2022)Rite Aid Corporation — 2,200,000 affected (OR, 2024)U-Haul International, Inc. — 2,195,831 affected (OR, 2022)Eddie Bauer LLC — 2,192,422 affected (OR, 2016)Navia Benefit Solutions, Inc. — 2,151,330 affected (WA, 2026)T-Mobile USA — 2,079,648 affected (WA, 2021)FlightAware — 2,000,000 affected (OR, 2024)Zeroed-In Technologies, LLC — 1,977,486 affected (OR, 2023)Cerner Corporation — 1,970,332 affected (OR, 2025)Financial Business and Consumer Solutions, Inc. — 1,955,385 affected (OR, 2024)Insightin Health, Inc. — 1,949,534 affected (MD, 2026)Rivers Casino Philadelphia — 1,942,182 affected (OR, 2025)Anne Arundel Dermatology — 1,905,000 affected (MD, 2025)Apria Healthcare LLC — 1,869,598 affected (OR, 2023)Summit Pathology and Summit Pathology Laboratories, Inc. — 1,813,538 affected (CO, 2024)Running Warehouse LLC — 1,813,224 affected (OR, 2021)Skate Warehouse LLC — 1,813,224 affected (OR, 2021)Tennis Warehouse LLC — 1,813,224 affected (OR, 2021)Tackle Warehouse LLC — 1,813,224 affected (OR, 2021)Shields Health Care Group, Inc. — 1,804,069 affected (OR, 2022)New York City Health and Hospitals Corporation — 1,800,000 affected (NY, 2026)WSSC WATER — 1,800,000 affected (OR, 2021)Insightin Health, Inc. — 1,777,141 affected (TX, 2026)PH TECH — 1,752,083 affected (OR, 2023)OnePoint Patient Care — 1,741,152 affected (OR, 2024)PH TECH — 1,700,000 affected (OR, 2023)Kettering Adventist Healthcare — 1,695,382 affected (OH, 2025)Fred Hutchinson Cancer Center — 1,694,184 affected (WA, 2023)Slim CD, Inc. — 1,693,000 affected (OR, 2024)NEC Networks, LLC d/b/a CaptureRx — 1,656,569 affected (OR, 2021)Welltok, Inc. — 1,648,848 affected (OR, 2023)Laboratory Services Cooperative — 1,600,000 affected (OR, 2025)TIO Networks USA, Inc. (TIO.com), Cricket Wireless LLC, and Pacific Gas and Electric Company — 1,600,000 affected (OR, 2017)Flagstar Bank, FSB — 1,547,169 affected (OR, 2022)Strategic Education Inc. — 1,513,518 affected (OR, 2026)Strategic Education Inc. — 1,513,518 affected (TX, 2026)The Phia Group, LLC — 1,512,742 affected (TX, 2026)Keenan & Associates — 1,509,616 affected (OR, 2024)Allianz Life Insurance Company of North America — 1,497,036 affected (TX, 2025)Wilton Reassurance Company — 1,482,490 affected (OR, 2023)ALN Medical Management, LLC — 1,466,801 affected (TX, 2025)American Bar Association — 1,466,442 affected (OR, 2023)Flagstar Bank, FSB — 1,465,002 affected (OR, 2021)ACTIVEOutdoors — 1,449,645 affected (WA, 2016)Washington State Auditor's Office — 1,420,520 affected (WA, 2021)Radiology Associates of Richmond, Inc. — 1,419,091 affected (VA, 2025)Baptist Medical Center — 1,416,691 affected (OR, 2022)Kaplan North America LLC — 1,403,060 affected (TX, 2026)Kaplan North America, LLC — 1,400,000 affected (OR, 2026)Xsolis, Inc. — 1,396,519 affected (TN, 2026)Xsolis, Inc. — 1,396,519 affected (TX, 2026)PIH Health, Inc. — 1,369,533 affected (TX, 2026)DermCare Management — 1,367,176 affected (TX, 2026)DermCare Management — 1,361,735 affected (FL, 2025)North Broward Hospital District d/b/a Broward Health — 1,357,879 affected (OR, 2022)JERICO PICTURES, INC. D/B/A NATIONAL PUBLIC DATA — 1,350,684 affected (OR, 2024)GameStop, Inc — 1,338,102 affected (OR, 2017)State of Maine — 1,324,118 affected (OR, 2023)LoanCare, LLC — 1,316,938 affected (OR, 2023)Milliman Solutions LLC — 1,280,823 affected (OR, 2023)SimonMed Imaging — 1,275,669 affected (AZ, 2025)SimonMed Imaging — 1,275,669 affected (TX, 2025)Pawn America Minnesota, LLC — 1,272,402 affected (OR, 2021)Pingora Loan Servicing, LLC — 1,268,248 affected (OR, 2022)The Georgia Institute of Technology — 1,265,883 affected (OR, 2019)Baptist Medical Center — 1,243,031 affected (OR, 2022)MCBS LLC — 1,241,154 affected (TX, 2026)Purfoods, LLC — 1,237,681 affected (OR, 2023)Nuance Communications Inc — 1,225,054 affected (OR, 2023)Absolute Dental Group, LLC — 1,223,635 affected (OR, 2025)Absolute Dental Group, LLC — 1,223,635 affected (TX, 2025)Absolute Dental Group, LLC — 1,223,635 affected (NV, 2025)MHNext LLC (d/b/a Manhunt) — 1,200,000 affected (OR, 2021)WestJet — 1,200,000 affected (OR, 2025)WestJet — 1,200,000 affected (TX, 2025)GoDaddy.com, LLC — 1,200,000 affected (OR, 2021)CHSPSC, LLC — 1,173,555 affected (OR, 2023)American Anesthesiology, Inc. — 1,159,841 affected (OR, 2021)Insightin Health, Inc. — 1,144,686 affected (OR, 2026)Southeast Series of Lockton Companies, LLC (Lockton) — 1,124,727 affected (GA, 2025)Washington State University — 1,118,135 affected (OR, 2017)Topgolf Callaway Brands Corp. — 1,114,954 affected (OR, 2023)Berry, Dunn, McNeil & Parker, LLC — 1,107,354 affected (OR, 2024)NCB Management Services, Inc. — 1,087,842 affected (OR, 2023)One Touchpoint, Inc. — 1,073,316 affected (OR, 2022)Farmers Insurance Exchange, Farmers Group, Inc. (its attorney-in fact), and their subsidiaries and affiliates — 1,071,300 affected (TX, 2025)Community Health Center, Inc. — 1,060,936 affected (CT, 2025)AT&T Inc. — 1,060,051 affected (SC, 2024)NextGen Healthcare, Inc. — 1,049,375 affected (OR, 2023)Inova Health System — 1,045,270 affected (OR, 2020)Six Continents Hotels, Inc. (d/b/a InterContinental Hotels Group) — 1,043,686 affected (OR, 2017)ZOLL Medical Corporation — 1,004,443 affected (OR, 2023)The Hertz Corporation, on behalf of Hertz, Dollar, and Thrifty — 1,000,175 affected (OR, 2025)Boy Scouts of America — 981,068 affected (WA, 2020)University of Washington Medicine — 974,351 affected (OR, 2019)The Global Atlantic Financial Group LLC (“Global Atlantic”) — 972,485 affected (OR, 2023)Young Consulting LLC — 954,177 affected (OR, 2024)Astoria Company LLC — 940,000 affected (OR, 2021)Frederick Health — 934,326 affected (MD, 2025)DaVita Inc. — 915,952 affected (OR, 2025)DaVita Inc. — 915,952 affected (TX, 2025)Transformative Healthcare — 911,757 affected (OR, 2023)ATSG, Inc — 909,469 affected (NY, 2024)University of Washington Medical Center — 894,272 affected (WA, 2019)Finastra Technology, Inc. — 888,627 affected (OR, 2025)Valley Anesthesiology Consultants, Inc., d/b/a Valley Anesthesiology and Pain Consultants — 882,590 affected (OR, 2016)Navvis & Company, LLC — 874,506 affected (OR, 2023)Fidelity & Guaranty Life Insurance Company (“F&G”) — 873,000 affected (OR, 2023)Columbia University — 868,969 affected (OR, 2025)Texas Tech Health University Sciences Center El Paso — 868,133 affected (OR, 2025)Baesman Group, Inc. — 863,812 affected (OR, 2024)Partnership HealthPlan of California — 854,913 affected (OR, 2022)QuoteWizard — 852,079 affected (OR, 2024)Jackson National Life Insurance Company — 845,644 affected (OR, 2023)SouthState Bank — 844,672 affected (SC, 2024)Flagstar Bank, N.A. — 837,390 affected (OR, 2023)City of Hope — 827,149 affected (OR, 2024)Delta Air Lines, Inc. — 825,000 affected (OR, 2018)Ethos Group, Inc. — 822,723 affected (OR, 2022)Texas Tech University Health Sciences Center El Paso — 815,000 affected (TX, 2024)Texas Tech University Health Sciences Center — 813,892 affected (TX, 2026)Texas Tech University Health Sciences Center — 813,892 affected (OR, 2026)MGM Resorts International — 811,740 affected (WA, 2023)NASCO — 804,862 affected (OR, 2023)Bankers Life — 799,563 affected (OR, 2018)OnePoint Patient Care — 795,916 affected (OR, 2024)Fidelity National Information Services, Inc. — 793,626 affected (OR, 2023)UNITE HERE — 791,273 affected (OR, 2024)Caesars Entertainment, Inc. — 784,234 affected (WA, 2023)T-Mobile USA — 772,593 affected (WA, 2023)Washington State University — 769,088 affected (WA, 2017)Motility Software Solutions Inc — 766,670 affected (TX, 2025)