A massive data breach at National Public Data (NPD) has exposed the personal information, including Social Security numbers, of billions of Americans. The breach, attributed to a 'third-party bad actor,' occurred in December 2023, with data leaks continuing through April and summer 2024. Hackers have since posted 2.9 billion records for sale on the dark web, and several class-action lawsuits have been filed against NPD. Affected individuals are advised to monitor their financial accounts, set up fraud alerts with credit agencies, and consider a credit freeze. Cybersecurity firms like Pentester have launched tools to help individuals check if their data was compromised. NPD has stated it is cooperating with law enforcement and will notify affected individuals if significant developments occur.