A running list of the largest reported data breaches affecting Americans.
Data breaches have exposed billions of personal records over the past two decades. When organizations fail to protect sensitive information, criminals can use that data for identity theft, fraud, and financial crimes.
This leaderboard highlights some of the largest known breaches affecting individuals and organizations. Data Breach Alert tracks these incidents to help people understand the growing risks to their personal information.
| Rank | Organization | Year | Records Exposed | Types of Data |
| 1 | Yahoo | 2013-2014 | 3 Billion | names, emails, passwords |
| 2 | Aadhaar | 2018 | 1.1 Billion | Identity data |
| 3 | First American Financial | 2019 | 885 Million | Financial records |
| 4 | Marriott | 2018 | 500 Million | Passport & travel data |
| 5 | 2019 | 533 Million | Phone numbers & emails | |
| 6 | Equifax | 2017 | 147 Million | SSNs, DOB, addresses |
Largest Healthcare Data Breaches
| Rank | Organization | Year | Records Exposed | Types of Data |
Why Large Data Breaches Matter
Large data breaches often expose:
- Names
- Email addresses
- Passwords
- Social Security numbers
- Financial information
- Medical records
Even years after a breach occurs, criminals may still trade or sell stolen information on underground markets.
Monitoring breach activity helps individuals stay aware of potential identity theft risks.
Stay Ahead of Data Breaches
Data Breach Alert monitors reported breaches and notifies subscribers when incidents may affect their personal information.
You can also explore recent incidents on the Data Breach Alert National Breach Map.
See our recommended Resources.
Become personally enlightened on our How It Works page.
Data Sources
Data breach information is compiled from publicly reported incidents including resources from:
- Identity Theft Resource Center
- Federal Trade Commission
- state attorney general breach notifications
- industry cybersecurity reports
The Scale of the Data Breach Problem
Recent studies estimate that hundreds of millions of personal records are exposed every year, affecting individuals, businesses, and government agencies.
Identity theft remains one of the most commonly reported crimes in the United States.
~~~ Last Updated: March 2026 ~~~